Category Archives: Colon Cancer

Buy a Sleep Mask! It’s an Investment in Your Health

Jessica Becker, Cancer Prevention and Treatment Fund

A study published in 2023 found that wearing an eye mask to block light while sleeping overnight in the home improves memory and alertness the next day.  That should help with driving, learning, and other important activities5.

The new research did not evaluate why the eye mask was so beneficial, but previous research shows that sleeping in total darkness allows your body to produce as much of the hormone melatonin as possible. This is good because when your production of melatonin drops, you are at greater risk of breast and/or colorectal cancer and other health risks.

What is Melatonin?

Melatonin is a hormone that is naturally produced in your body. It is secreted by the pineal gland, which is buried deep in the brain. Melatonin is only produced at night and only when it is dark, which means that melatonin production peaks between 3:00 a.m. and 5:00 a.m. for most people. This hormone helps to regulate your circadian rhythm, which is like your body’s natural clock. When melatonin and several other chemicals are released, you feel drowsy and your body temperature lowers. In addition to this sleep-cycle function, melatonin also works as an antioxidant. This means that it can help prevent damage to your DNA that can result from aging, exposure to cancer-causing chemicals, or harmful rays from the sun. Preventing damage to DNA is important because DNA damage can cause cancer.

Doesn’t My Body Produce Enough Melatonin?

There have been major advancements in technology over the last two centuries, one being the light bulb. Because of the light bulb (and electricity, in general), we are able to stay awake and active much later, so the night is not as dark as it used to be. Think of New York City: the city that never sleeps. Cities are so lit up at night that it can be hard to see the stars. This is referred to as “light pollution.”  And, of course, even in the middle of nowhere, you can keep your lights on all night in your house.

Our ability to turn night into day has allowed for more night shift work, often called “the graveyard shift.” Even if you don’t work on the late shift, you may be working at home late at night or staying up late watching TV or using the internet.  Unfortunately, this kind of schedule has many effects on your body, including reducing the amount of melatonin produced. But it is not just night owls or shift workers who suffer from a decreased production of melatonin. Sleep studies show that almost everyone wakes up at some point during the night, even if we do not remember it. Unless you have blackout shades on your windows, there is a good chance that some light is coming into your bedroom and that your eyes are registering this light during those wakeful periods.[2]

New technology is compounding the effects of light pollution. Early incandescent light bulbs that were dim and yellow and did not affect melatonin production very much. Now, artificial light emits more blue wavelengths. For example “Cool White” fluorescent bulbs are a very popular choice of light bulb because they are bright, moderately energy efficient, and relatively inexpensive. They also produce a lot of blue light which is why they have a “cool” effect. Maybe you have noticed while driving that certain people’s headlights appear to be very bright and have a blue tint to them. These new headlights produce blue wavelengths of light. Unfortunately, research shows that blue wavelengths of light are especially effective at reducing melatonin production in humans.[3] All types of computer monitors and television screens also emit blue light.

Why Is Having Less Melatonin A Bad Thing?

Believe it or not, the International Agency for Research on Cancer (IRAC) classified shift work as a probable human carcinogen in 2007. There have been numerous studies showing a link between night shift work and an increased incidence of breast cancer. For instance, a 2003 study done in the Netherlands found that by working half a year at night, a person’s risk of breast cancer increased 150%.[3] This major study found that nurses who worked night shifts at least 3 times a month for 15 years or more had a 35% increased risk of colorectal cancer.[3] If you’re still unconvinced, a 2009 study conducted in 147 communities in Israel found that women who lived in neighborhoods where it was bright enough to read a book outside at midnight had a 73% higher risk of developing breast cancer than women living in areas without outdoor lighting.[2]

What Can I Do To Limit My Chances Of Getting Cancer Because of Light At Night?

The good news is that there are easy and inexpensive ways to limit the amount of light you are exposed to at night. For starters, if you have electronic appliances in your bedroom that produce light (like a clock radio or cable box), pick those that have red lights as opposed to green or blue lights. Walmart, Target, Best Buy, and many other stores all carry alarm clocks and radios that display the time in red numbers. These brands are not more expensive than their blue numbered counter-parts. Studies show that red lights don’t cause as much of a decrease in the amount of melatonin produced by your body.[4] Also, if you have a television or computer in your bedroom, turn it off before you go to sleep.

It is also a good idea to limit the amount of time you spend in front of a screen at night. If you spend a few hours a night in front of your computer, whether or not you’re not in your bedroom, you are decreasing the amount of melatonin that is being produced in your brain. Most screens today offer a “night mode” which reduces the amount of blue light used and creates an orange tint. This is a recommended setting to use before bed.

Also, since melatonin production is highest between the hours of 3:00 am and 5:00 am, make sure you’re in bed and asleep by 3:00 a.m., and if at all possible, sleep until at least 5:00 am. While you probably will not be able to petition your community to get the street light in front of your house turned off, you can buy blackout shades to block the light. Most department stores sell blackout shades, and they are relatively inexpensive. If you don’t want to invest a penny more in “window treatments,” consider using a sleep mask. Airlines sometimes give them away in travel kits, but you can also buy them online or in a department store. Besides lowering the risk of getting certain cancers, sleep masks can also help you fall asleep faster, have a better night’s sleep, and feel much better the next day. Those are great benefits for such a simple, no-risk strategy.

All articles on our website have been approved by Dr. Diana Zuckerman and other senior staff. 

  1. Navara J, Nelson R. The Dark Side Of Light At Night: Physiological, Epidemiological, and ecological consequences. Journal of Pineal Research. 2007, (43)
  2. Chepesiuk R. Missing the Dark: Health Effects of Light Pollution. Environmental Health Perspectives. 2009, (117)
  3. Pauley S. Lighting For The Human Circadian Clock: Recent Research Indicated That Lighting Has Become A Public Health Issue. Medical Hypotheses. 2003
  4. Reiter R. Circadian Disruption and Cancer: Making the Connection. The New York Academy of Sciences. 2009
  5. Greco, V., Bergamo, D., Cuoccio, P., Konkoly, K. R., Muñoz Lombardo, K., & Lewis, P. A. (2023). Wearing an eye mask during overnight sleep improves episodic learning and alertness. Sleep, 46(3), zsac305.

Alcohol and Cancer

Ealena Callender, MD, MPH, & Meg Seymour, PhD, Cancer Prevention and Treatment Fund

The link between alcohol and cancer may surprise you. The American Society of Clinical Oncology reports that drinking alcohol increases the risk of cancer of the mouth and throat, vocal cords, esophagus, liver, breast, and colon. The risks are greatest in those with heavy and long-term alcohol use. Even so, moderate drinking can add up over a lifetime, which could be harmful.1

What is Moderate Drinking? Heavy Drinking?

The 2020-2025 Dietary Guidelines for Americans recommends that Americans can reduce their risk of alcohol-related health problems by drinking in moderation, which means 1 drink per day or less for women and 2 drinks per day or less for men.2 However, not all “drinks” are equal. A drink is defined as approximately 0.6 fluid ounces of alcohol, which equals: 1.5 ounces of distilled spirits (e.g., vodka, gin, tequila, etc), 5 ounces of wine, 12 ounces of beer, and 8 ounces of malt liquor.3 (Click here to see the CDC’s fact sheet.) The guidelines define moderate drinking as two drinks or less per day for men and one drink or less per day for women.

The CDC describes heavy drinking as having more than eight drinks per week for women and more than 15 drinks per week for men. Binge drinking refers to consuming multiple drinks on a single occasion – four or more drinks for women and five or more drinks for men.

Drinking and Cancer

In January 2023, the Canadian Centre on Substance Use and Addiction (CCSA) published updated guidelines that recommend limiting alcohol use to two or fewer drinks per week to reduce the risk of harm from alcohol.4 At that level, they say risk of harm from alcohol is low. Risk is moderate for those who drink three to six servings of alcohol per week and “increasingly high” for those who drink seven or more. The report warns that drinking three to six alcoholic beverages per week is associated with increased risk of several types of cancer.

These guidelines may surprise many people, especially those who assumed moderate drinking was not anything to be concerned about.  But research indicating the risk of cancer from drinking even small amounts of alcohol has been published for years.  For example, Alcohol is known to cause at least six types of cancer: mouth and throat cancer, larynx (voice box) cancer, esophageal cancer, colon and rectal cancer, liver cancer, and breast cancer in women.5 A 2021 study found that 4% of all new cancer cases diagnosed throughout the world in 2020 were attributable to alcohol consumption, and the researchers say that may be a low estimate.6

Depending on the amount a person drinks, they can increase their chances for developing even rare cancers. For example, moderate drinkers can almost double their lifetime risk of mouth and throat cancer to almost 2%, while heavy drinkers increase their risk of having mouth or throat cancer, from 1% to 5%.1 A 2020 study from Australia found that the heaviest drinkers (drinking more than 14 drinks per week) had an overall higher likelihood of developing cancer, compared with those who drank the least (1 or 0 drinks per week). The men who drank the most had a 4.4% higher overall likelihood of developing cancer than the men who drank the least, and the women who drank the most had a 5.4% higher overall chance of developing cancer.7

Women need to be more cautious about drinking any amount of alcohol because the alcohol is even more likely to cause cancer in women than in men. Research has shown that women who drink even 1 drink per day have a 5-9% higher chance of developing breast cancer, compared with women who do not drink.8 The risk is even higher for women who drink more. One reason may be that alcohol affects the amounts of certain sex hormones circulating in the body. For women who have had hormone receptor-positive breast cancer, seven or more weekly drinks increased the chances of having a new cancer diagnosed in the other breast from about 5% to about 10%.1

Heavy drinking is also risky for those who currently have or have had other types of cancer. Among all cancer survivors, heavy drinking caused an 8% increased risk in dying and a 17% increased risk of cancer recurrence. Patients with cancer who abuse alcohol do worse because alcohol causes poorer nutrition, a suppressed immune system, and a weaker heart.1

In 2020, an estimated 100,000 cases of cancer globally were caused by light to moderate drinking (fewer than two alcoholic beverages per day).6 A study of alcohol use in the European Union found that a drinking level of less than one drink per day was linked to 40% of alcohol-related cancers in women and 32% in men.9

Individuals who increase their alcohol use may also increase their chance of getting cancer, according to a large 2022 study.10 Compared with men and women who maintained the same level of drinking over about six years, the study found that those who increased their alcohol consumption were more likely to get cancer. While those who increased their alcohol consumption most dramatically saw a more significant increase in their risk of cancer, even those who only increased their consumption by a small amount had a higher risk of cancer than those who did not change their level of drinking.

How Alcohol Causes Cancer

Scientists believe that alcohol causes cancer in several ways:1

  • Alcohol (ethanol) is broken down into a toxic substance called acetaldehyde, which is directly toxic to the body’s cells.
  • Alcohol causes damage to cells through a process called free-radical oxidation.
  • Alcohol causes the body to absorb less folate (an important B vitamin) and other nutrients (antioxidant vitamins A, C, and E), which naturally repair damage and fight off cancers.
  • Alcohol increases the body’s level of estrogen (a sex hormone associated with breast cancer)

What You Can Do to Lower Cancer Risk for You and Your Family

  • If you drink alcohol, limit drinks to an average of 1 a day for women and 2 a day for men.
  • Recognize heavy drinking in a loved one,because the more a person drinks, the greater his or her chances of developing cancer. The “CAGE” questionnaire provided here can help spot heavy drinking.
    1.   Has the person tried to Cut back?
    2.   Has the person been Annoyed when asked about drinking?
    3.   Has the person felt bad or Guilty?
    4.   Has the person needed a drink first thing in the morning (Eye opener)? Each “yes” counts as 1 point. A score of 2 or more suggests problem drinking.
  • Talk with your doctor about your risk.Doctors can refer or offer counseling and treatment services to patients with risky drinking habits.
  • Seek help early. Problem drinking can’t be wished away. There are many resources to access information and help. The Substance Abuse and Mental Health Services Administration (SAMHSA), which is part of the U.S. Department of Health and Human Services (HHS) has a toll free hot-line and website. Call 1-800-662-HELP (4357) or visit
  • Practice healthy habits. Eating a diet rich in cancer-fighting nutrients (i.e., fruits and vegetables), exercising, maintaining a healthy weight, reducing stress, and getting restful sleep can all help to lower cancer risk. Don’t smoke, and quit if you do. Drinking and smoking increases cancer risk more than either one alone.

The Bottom Line

To decrease your chances of cancer and other serious health problems, try to limit your drinking.  If you drink alcohol, try to drink less often and aim for a maximum average of 1 a day if you’re a woman and 2 a day if you’re a man.

All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.

The National Center for Health Research is a nonprofit, nonpartisan research, education and advocacy organization that analyzes and explains the latest medical research and speaks out on policies and programs. We do not accept funding from pharmaceutical companies or medical device manufacturers. Find out how you can support us here.



1. LoConte NK, Brewster AM, Kaur JS, Merrill JK, Alberg AJ. Alcohol and cancer: a statement of the American Society of Clinical Oncology. Journal of Clinical Oncology. 2018;36(1):83-93.

2. U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition. December 2020. Available at

3. Centers for Disease Control and Prevention. Dietary Guidelines for Alcohol. Updated December 2020.


5. Centers for Disease Control and Prevention. Alcohol and Cancer. Updated July 2019.

6. Rumgay H, Shield K, Charvat H, Ferrari P, Sornpaisarn B, Obot I, Islami F, Lemmens VE, Rehm J, Soerjomataram I. Global burden of cancer in 2020 attributable to alcohol consumption: A population-based study. The Lancet Oncology. 2021;22(8):1071-80.

7. Sarich P, Canfell K, Egger S, Banks E, Joshy G, Grogan P, Weber MF. Alcohol consumption, drinking patterns and cancer incidence in an Australian cohort of 226,162 participants aged 45 years and over. British Journal of Cancer. 2021;124(2):513-23.

8. National Institute on Alcohol Abuse and Alcoholism. Women and Alcohol. Updated April 2021.

9. Rovira, P., & Rehm, J. (2021). Estimation of cancers caused by light to moderate alcohol consumption in the European Union. European journal of public health31(3), 591–596.

10. Yoo, J. E., Han, K., Shin, D. W., Kim, D., Kim, B. S., Chun, S., Jeon, K. H., Jung, W., Park, J., Park, J. H., Choi, K. S., & Kim, J. S. (2022). Association Between Changes in Alcohol Consumption and Cancer Risk. JAMA network open5(8), e2228544.


Beginner’s Guide to Developing an Exercise Routine

Morgan Wharton and Caitlin Kennedy, Cancer Prevention and Treatment Fund

Exercise is one of our seven recommended ways to maximize your health. It will reduce your chances of developing cancer and of living longer after your diagnosis.[1]  If you want to exercise but aren’t sure where to begin, we can help! If you feel like your daily life doesn’t allow you to get fit (not enough time, no money for a gym membership, etc.), we have some “work-arounds” that may help.

Benefits of Exercise

Everyone knows that exercise helps keep you healthy by preventing weight gain, but did you know that it also lowers your risk of heart disease, stroke, high blood pressure, unhealthy cholesterol, type 2 diabetes, and depression?[2,3] In addition, a study published in 2020 reported that a physically active lifestyle is even associated with less likelihood of developing cancer, or of dying of cancer.[4] Exercising to improve muscle strength also improves balance, and reduces the risk of falling, fractures, and arthritis. Overall, regular exercise improves your chances of living longer and helps you have a higher quality of life.[2]   

Even people who have been diagnosed with cancer can benefit from exercise. Click here to read more how exercise can help cancer patients.

How Much Should I Exercise?

The Centers for Disease Control and Prevention (CDC) recommend that adults should aim for 150 minutes of moderate-intensity exercise every week (such as walking quickly) or 75 minutes of high-intensity activity per week (such as running), plus two days of strength training (training with weights or resistance bands). If you haven’t been very active, start exercising at a low intensity, then slowly increase the amount and intensity of exercise each week.[5]

A 2017 study found that any amount of physical activity can reduce the chances of dying from cardiovascular disease or cancer. This means that if you regularly exercise, are a “weekend warrior,” or are less active than the CDC recommends, that will still help you live longer than not exercising at all.[6]

How Do I Create an Exercise Routine?

Regardless of your fitness goals, start small to avoid discouragement or burnout: if you set your initial goals too high and aim for perfection, you’ll be more likely to abandon your exercise plans before they improve your health. Follow these exercise routines from the CDC to create a balanced, varied routine.

To prevent injury, always start your workout with a good warm up-short aerobic activity followed by dynamic stretching. Dynamic stretching involves moving different muscle groups through a full range of motion and is the best form of stretching before exercise because it warms up groups of muscles rather than individual muscles. Static stretching, such as holding a muscle in a position of resistance for up to 30 seconds, is helpful for improving flexibility and muscle imbalance over time, but is not beneficial just before exercising.[7] Investing in good running shoes will also help with preventing injuries such as shin splints that can develop after running on hard surfaces with the wrong kind of footwear.

If you don’t feel up to completing a full workout or are too busy on a given day, even taking the stairs instead of an elevator or escalator, walking around while you make phone calls, or walking to work or during your break can make up your exercise for the day. Even if it’s a shorter, less intense workout, it’s always best to get some activity each day, and you might be more likely to continue if you get others involved. Form a walking group and walk to work with people who live near you, or walk together on your daily breaks. If you don’t have a group of people to exercise with at work, consider using social media to benefit from peer pressure. Also upload your progress and fitness goals on sites like Facebook and Twitter.

Keeping track of your fitness goals and exercise can help you form a routine until exercise becomes a habit. If you don’t want to use mobile technology to keep track of your exercising, check out some tools designed by the U.S. Department of Health & Human services for other ways to track your fitness goals and routines.

In addition to running- and movement-based exercise, weight training is very valuable. If you enjoy weight lifting, joining a gym can add a financial incentive to working out: if you’ve already paid for a membership, you’ll have more reason to go and get your workout in! If you need more motivation to get to the gym, check out GymPact – you can get paid just for completing workouts at your gym! If you aren’t sure how to use the machines in the gym, check out these instructional videos for better technique.

Whether or not you go to a gym, there are plenty of ways to get a good workout at home! You can get a great workout with bodyweight exercises alone. Use this guide from the National Institutes of Health to begin resistance training and weight lifting at home. Investing in a jump rope, balance ball, medicine ball, resistance bands, and 5-pound dumbbells can give you more flexibility with your workouts. Variation is important to get the most benefits from exercise and prevent boredom from the same routines. Many apps can be effective exercise tools such as the Nike Training Club app for smartphones which has free workouts, sorted by difficulty, that can be done with basic equipment. The app also tracks your progress and adds new workouts once you reach specific milestones based on the number of minutes you’ve exercised.

Signing up for a race is a great way to motivate you to begin an exercise routine. It gives you a deadline to work towards – the date of the race – and a concrete goal to train for – the length of the race.  A 5k is a great first race to train for because it’s only 3.14 miles.

Avoiding the Risks of Exercise


People who exercise outside and do not drink enough water put themselves at risk for heat stroke and exhaustion. Drink plenty of water beginning the day before you exercise, and drink 10 ounces of water for every 20 minutes of exercise. Drink before you get thirsty, because thirst is the first sign of dehydration.[8] Finally, beware of the dangers of water bottles containing BPA. Be sure to select a stainless steel bottle or a plastic water bottle that is labeled “BPA free.” Read more about the harmful effects of BPA here.


While running and exercising outside, remember to apply sunscreen of SPF 30 or higher that offers full spectrum protection (protection against both UVA and UVB rays) and is water-resistant. Apply at least fifteen minutes before going outside to allow your skin to soak up the sunscreen. Reapply often-every two hours and after swimming and excessive sweating. You should also apply lip balm of at least SPF 30. This will reduce your risk of sunburn, skin cancer, and premature aging of the skin.[9] Read more about running and skin cancer here.


Overtraining can put too much stress on the immune system and keep it from doing its job, which is to keep you from getting sick! People who overtrain put themselves at risk of developing illnesses like colds and the flu because their immune systems are “run down.” You may feel fatigued all the time, or find yourself getting injured.  Some soreness and fatigue is a normal part of training, but if your discomfort becomes excessive, increase your rest/recovery time in between workouts.[10]

Regular endurance exercise may be risky, as well.  Running more than 30 miles per week may lessen or erase the health benefits, including a longer life, which moderate levels of running provide.  People who run a lot of marathons have been found to have higher levels of coronary plaque, a type of heart disease and a cause of heart attacks.[10] Therefore, moderate levels of regular exercise are recommended.

The Bottom Line

The potential benefits far outweigh the potential risks of regular exercise. Grab a friend, use social media, and register for a race to keep your motivation levels high until exercise becomes a part of your daily routine. Regular physical activity can improve your physical health, and also your mood and overall mental well-being. Maybe you’ve heard of a “runner’s high” – well, you don’t have to be a runner to experience the calming effects of exercise.  If you want to experience these health benefits and live a longer, healthier life, now is the time to begin a fitness routine!

All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.

The National Center for Health Research is a nonprofit, nonpartisan research, education and advocacy organization that analyzes and explains the latest medical research and speaks out on policies and programs. We do not accept funding from pharmaceutical companies or medical device manufacturers. Find out how you can support us here.

  1. Chen et, al. Association of physical activity with risk of mortality among breast cancer survivors. JAMA Netw Open.2022;5(11):e2242660. doi:10.1001/jamanetworkopen.2022.42660
  2. Centers for Disease Control and Prevention. Benefits of Physical Activity. Updated August 2020. 
  3. World Health Organization. Physical activity. Updated 2018.
  4. Gilchrist SC, Howard VJ, Akinyemiju T, Judd SE, Cushman M, Hooker SP, Diaz KM. Association of Sedentary Behavior With Cancer Mortality in Middle-aged and Older US Adults. JAMA Oncology. 2020;6(8):1210–1217.
  5. Centers for Disease Control and Prevention. How much physical activity do adults need?. Updated May 2020. 
  6. O’Donovan G, Lee IM, Hamer M, Stamatakis E. Association of “weekend warrior” and other leisure time physical activity patterns with risks for all-cause, cardiovascular disease, and cancer mortality. JAMA Internal Medicine. 2017; 177(3):335-42.
  7. Parracino, L. A Simple Guide to Stretching. 2002.
  8. American Council on Exercise. Healthy Hydration. 2012. 
  9. American Academy of Dermatology. SUNSCREEN FAQS.
  10. Kellmann M. Preventing overtraining in athletes in high‐intensity sports and stress/recovery monitoring. Scandinavian Journal of Medicine & Science in Sports. 2010; 20:95-102.
  11. Mohlenkamp S, Lehmann N , Breuckmann F, Brocker-Preuss M, Nassenstein K, Halle M, Budde T, Mann K, Barkhausen J, Heusch G, Jockel K, & Erbel R. Running: The risk of coronary events. Prevalence and prognostic relevance of coronary atherosclerosis in marathon runners. European Heart Journal, 2008. 29(15): p. 1903-1910.

Can Aspirin Prevent Cancer?

Diana Zuckerman, PhD: Cancer Prevention and Treatment Fund

Many Americans take low-dose aspirin, also called baby aspirin, to prevent cancer and heart disease.  However, by 2019, the latest research suggested that aspirin is not as helpful as many patients believe.

In 2016, the U.S. Preventive Service Task Force (USPSTF), an independent group of medical experts, recommended low-dose aspirin “for the primary prevention of cardiovascular disease (CVD) and colorectal cancer (CRC) in adults aged 50 to 59 years who have a 10% or greater 10-year CVD risk [risk of developing cardiovascular disease], are not at increased risk for bleeding, have a life expectancy of at least 10 years, and are willing to take low-dose aspirin daily for at least 10 years”.1   They did not recommend aspirin to prevent all types of cancer, only colorectal cancer.

Primary prevention means preventing a disease that a person has not yet developed. As you can see above, there were quite a few caveats on who might benefit from “baby” low dose aspirin (typically 81mg).  For example, patients with an increased risk of bleeding due to certain medications, or with a history of other medical conditions such as stomach or intestinal ulcers, kidney disease, or severe liver disease.1

Recommended Guidelines in 2019 from the American College of Cardiology (ACC) and the American Heart Association were not as enthusiastic about aspirin for primary prevention of heart disease, saying that “low-dose aspirin might be considered” for certain patients.2  They did not comment on aspirin to prevent cancer.

Studies  published almost a decade ago had mixed results for cancer prevention. One study suggested that a daily dose of at least 75mg aspirin taken for several years could reduce the risk of developing colorectal cancer or dying from it.3 Other studies suggested that aspirin may reduce mortality from other cancers, as well as reducing the chances of cancer spreading.4,5 However, a 2019 meta-analysis that combined results from several studies found aspirin did not significantly affect cancer mortality.6  One clinical trial known as ASPREE (Aspirin in Reducing Events in the Elderly) found that individuals who took aspirin were more likely to die from cancer.

In conclusion, more research is needed to conclusively determine whether daily baby aspirin can help to prevent cancer.

BottomlineDo I Need Aspirin?

Some patients think they may as well take aspirin, because it might help and won’t harm.  That’s not an accurate assumption.  Aspirin can have risks even at low doses. You should discuss aspirin therapy with your doctor and let him or her know:

  • Your medical history and the medicines you are currently using, whether they are prescription or over-the-counter
  • Any allergies or sensitivities you may have to aspirin
  • Any vitamins or dietary supplements you are currently taking

Other Ways to Prevent Heart Disease and Cancer

To reduce your risk of colorectal cancer, don’t smoke, don’t drink alcohol in excess, have a healthy diet, stay physically active, and maintain a healthy weight.  Being older, and having a family history of colon cancer, Crohn’s disease, or ulcerative colitis are the risk factors you can’t control.7

To reduce your risk of heart disease, don’t smoke, keep your cholesterol and blood pressure under control, and do what you need to do to prevent diabetes.  Being a man and older are risk factors you can’t control.8

All articles on our website have been approved by Dr. Diana Zuckerman and other senior staff.


  1. Final recommendation statement: Aspirin use to prevent cardiovascular disease and colorectal cancer: Preventive Mmedication. U.S. Preventive Services Task Force. 2017.
  2. Donna K. ArnettRoger S. Blumenthal,  Albert MA, et al. 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease. Journal of the American College of Cardiology. 2019;17:CIR0000000000000678.
  3. Rothwell PM, Wilson M, Elwin CE, et al.  Long-term effect of aspirin on colorectal cancer incidence and mortality: 20-year follow-up of five randomised trials. Lancet. 2010;376(9754): 1741-50.
  4. Rothwell PM, Folkes FG, Belch JF, et al.  Effect of daily aspirin on long-term risk of death due to cancer: Analysis of individual patient data from randomised trials. Lancet. 2011;377(9759): 31-41.
  5. Rothwell PM, Wilson M, Price JF, et al. Effect of daily aspirin on risk of cancer metastasis: A study of incident cancers during randomised controlled trials. Lancet. 2012;379(9826): 1591-1601.
  6. Zheng SL, Roddick AJ.  Association of aspirin use for primary prevention with cardiovascular events and bleeding events: A systematic review and meta-analysis. JAMA. 2019;321(3):277-287.
  7. Colorectal Cancer Risk Factors. American Cancer Society.
  8. How to Prevent Heart Disease. Medline Plus.  Last reviewed 2015.

Colon Cancer: Who Is at Risk, and How Can It Be Prevented?

Noy Birger, Brandel France de Bravo, MPH, and Alea Sabry,  Cancer Prevention & Treatment Fund

When cancer begins in the colon (large intestine) or rectum, it is called colorectal cancer or colon cancer.

In the early stages, this cancer begins with small polyps, which are shaped like little mushrooms growing on the wall of the colon. Polyps are very common, especially as people get older. Not all polyps develop into cancer but all colorectal cancer begins with polyps. Certain kinds of polyps are more likely to lead to cancer than others, but the doctor can’t tell if a polyp is precancerous just by looking at it. This is why doctors prefer to remove and analyze any polyp found during screening. Polyps can be identified and removed by colonoscopy, in which a small camera on a flexible tube is inserted into the rectum.[1]

Thanks to more screening, the number of people diagnosed with colon cancer has decreased, but it is still the third most common cancer for both men and women.[2][3][4] The death rate is high because many people who are at risk for colon cancer do not get screened for the disease.[5]

A study published in February 2012 in New England Journal of Medicine found that patients who received colonoscopies and had noncancerous or pre-cancerous growths (polyps) removed, were half as likely to die from colon cancer than people in the general population who were not screened or used less effective screening methods. [6]

Men and women are equally likely to die from colon cancer, but men are more likely to be diagnosed with colon cancer than women of the same age.[7][8] Black men and Black women are at higher risk for developing colon cancer and dying from it than are white men and white women of the same age.[9][10] Being overweight or obese increases men’s risk of colon cancer more than it does women’s (see Weight and Cancer: What You Should Know).  In the U.S., nearly one in ten cases of colon cancer is estimated to be caused by excess body fat.[11]

Risk Factors for Developing Colon Cancer

In addition to your sex and race, your age and genes are important risk factors you can’t do anything about. Your chances of developing colon cancer increase as you get older: 90% of cases are in people over 50. Having a family member with colon cancer also increases your chances of developing it. About 20% of people with colon cancer have a first-degree relative (parents, siblings or children) or second-degree relative (aunts, uncles, grandparents, grandchildren, nieces, nephews, or half-siblings) who also had colon cancer. [12]

In addition to people with pre-cancerous polyps, people who suffer from ulcerative colitis or Crohn’s disease are more likely to develop colon cancer.[13] Ulcerative colitis and Crohn’s disease cause inflammation of the colon, which is why they are both also referred to as Inflammatory Bowel Disease (IBD). Chronic inflammations in the body seem to increase the risk of various types of cancer.

Less is known about what you can do to prevent colon cancer. People who eat too much fat in their diet or too little fiber or too little calcium, smoke, drink alcohol, don’t exercise enough, or are overweight are more likely to be diagnosed with colon cancer. However, scientists do not know whether people can lower their risks of getting colon cancer if they change one or more of those behaviors.  For example, several large research studies show that eating a high-fiber diet does not decrease your chances of getting colon cancer.[14][15][16] On the other hand, there is clear evidence that fiber, calcium, exercising, maintaining a healthy weight, and avoiding smoking and alcohol is generally good for your health, whether it reduces your chances of colorectal cancer or not.

So, What Can You Do to Lower Your Risk?

  • Get screened regularly from age 50 to 75. If you have a relative with colon cancer, your doctor may want to screen you earlier than age 50. The recommended screening tests are:
    • High Sensitivity Fecal Occult Blood Test (FOBT), which involves providing stool samples and should be done once every year
    • Colonoscopy (mentioned above), which requires anesthesia and is more expensive, and the doctor can remove polyps if found. It is only needed every 10 years unless a close relative developed colon cancer; and
    • Flexible sigmoidoscopy is similar to a colonoscopy. It can be used to find polyps but not to remove them. It is recommended every 5 years

A “virtual colonoscopy,” which is done with a Computed Tomography (CT) scan, is more expensive than the other screening tools and is not recommended by the U.S. Preventive Services Task Force. As with any CT scan, it exposes you to relatively high levels of radiation (see Everything You Ever Wanted to Know about Radiation and cancer, But Were Afraid to Ask).

The advantage to a regular colonoscopy (not a virtual one) over the other methods is that polyps can be removed during the screening process. The disadvantage is that you need to take a day off from work, fast for about 12 hours and purge with large quantities of an unpleasant laxative drink. The advantage of the FOBT is that it is easier and less expensive. However, the FOBT and CT scan only detect potential problems or polyps – you would still need the colonoscopy to have them removed if the results are abnormal. [17]

  • Quit smoking. Cigarette smoking doubles your chances of getting polyps and long-term smoking increases the risk of colon cancer. It also increases your chances of dying from colon cancer.[18][19][20]
  • Maintain a healthy weight. Extra pounds mean extra risk for all kinds of cancer, including colorectal cancer. Fat cells appear to trigger chronic inflammation of the body, which stresses the immune system.[21]
  • Eat a balanced diet. Be sure to include plenty of fruits and vegetables (especially ones from the cabbage family, like broccoli, cauliflower, cabbage, Brussels sprouts, and collard greens), limit the amount of red meat you eat (particularly well-done) and stay active. At least some of the research supports this kind of diet, and since eating this way offers so many different health benefits, why not try it? [22][23]
  • Get more Vitamin D through sunlight and supplements, since few foods are naturally rich in Vitamin D. Recent studies of doses higher than the 400 IU/day that is in standard multiple vitamins, show that Vitamin D can reduce the risk of colon cancer.[24] Blacks, who are at the highest risk for colon cancer, and people living in the northern half of the U.S., typically have too little Vitamin D in their bodies because they are exposed to less sun, and darker skin benefits less from sunshine.  And since Vitamin D is good for your health in many ways (see, it makes sense to give this a try if you are concerned about colon cancer.[25] Vitamin D is in milk and fortified breakfast cereals and in fatty fish such as tuna, salmon, and sardines, or you might consider a Vitamin D supplement.  Experts agree that adults can take up to 4,000 IU/day of Vitamin D without harming their health, and they recommend getting 5-30 minutes of sun at least twice a week. This means sun exposure to your face, arms or legs (preferably all three) without sun screen and between 10:00 a.m. to 3:00 p.m. However, too much Vitamin D can be dangerous.  The best way to make sure you are getting enough Vitamin D, but not too much, is to get your Vitamin D levels checked the next time you visit your doctor.
  • Low-dose aspirin. The U.S. Preventive Services Task Force found that taking low-dose aspirin can help prevent colorectal cancer and heart disease in some adults, depending on age and other factors. For more information, see: Aspirin Use for the Primary Prevention of Cardiovascular Disease and Colorectal Cancer: Consumer Guide. [PDF-212K]. Despite some early studies, there is no clear evidence that other types of anti-inflammatory products help prevent colorectal cancer, such as ibuprofen or fish oil tablets.
  • Reduce your intake of unnecessary antibiotics. A 2021 study found that people who took unnecessary antibiotics more frequently than others were more likely to develop early-onset colorectal cancer. Researchers believe that altering the gut microbiome structure through antibiotic treatment may increase one’s likelihood of developing colorectal cancer. Despite these findings, more studies are needed to understand the true role of antibiotics in colorectal cancer development, particularly to analyze the long-term effects of antibiotics on gut health.[26]

All articles on our website are reviewed and approved by Dr. Diana Zuckerman and other senior staff.

Related Content:

Have colon cancer? Skip the hot dogs, deli, and burgers
Colon cancer screening
Can aspirin prevent both heart disease and cancer?


1. Basic Information About Colorectal Cancer. Centers for Disease Control and Prevention.

2. “Cancer Among Women.” Centers for Disease Control and Prevention; 2015

3. American Cancer Society. Key Statistics for Colorectal Cancer. January 12, 2021.

4. “Cancer Among Men.” Centers for Disease Control and Prevention; 2015

5. Swan J, Breen N, Coates RJ, Rimer BK, Lee NC. Progress in cancer screening practices in the United States: results from the National Health Interview Survey.

6. Zauber AG, Winawer SJ, O’Brien M.J, Lansdorp-Vogelaar I, van Ballegooijen M, Hankey BF, et al. Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths. New  EnglandJournal of Medicine. 2012; 366(8), 687-696.

7. Fuchs CS, Giovannucci EL, Colditz GA, et al. Dietary Fiber and the Risk of Colorectal Cancer and Adenoma in Women. New England Journal of Medicine. 1999; 340:169-176.

8. Jemal A, Siegal R, Ward E, Hoa Y, Xu J, Thun MJ. Cancer Statistics 2009.  CA:A Cancer Journal for Clinicians.. 2009;59:225-249.

9. Lieberman D, Holub J, Moravec M, Eisen G, Peters D, Morris C. Prevalence of colon polyps detected by colonoscopy screening in asymptomatic black and white patients. Journal of American Medical Association. 2008;300:1417-1422.

10. Colorectal Cancer Rates by Race and Ethnicity. Centers for Disease Control and Prevention.

11. American Institute for Cancer Research. Researchers present data linking obesity/overweight to higher cancer risk, poorer cancer survival. November 2009.

12. Castels A, Castellvi-Bel S, Balaguer F. Concepts in familial colorectal cancer: where do we stand and what is the future? Gastroenterology. 2009; 137:404-409.

13. Jia Q, Lupton JR, Smith R, Weeks BR, Callaway E, Davidson LA, et al. Reduced Colitis-Associated Colon Cancer in Fat-1 (n-3 Fatty Acid Desaturase) Transgenic Mice. Cancer Research. 2008; 68: (10).

14. Fuchs CS, Giovannucci EL, Colditz GA, et al. Dietary Fiber and the Risk of Colorectal Cancer and Adenoma in Women. New England Journal of Medicine. 1999; 340:169-176.

15. Park Y, Hunter DJ, Speigelman D, Bergkvist L, Berrino F, van den Brandt PA, et al. Dietary Fiber Intake and Risk of Colorectal Cancer: A Pooled Analysis of Prospective Cohort Studies. Journal of American Medical Association. 2005; 294:2849-2857.

16. Schatzkin A, Mouw T, Park Y, Subar AF, Kipnis V, Hollenbeck A, et al. Dietary fiber and whole-grain consumption in relation to colorectal cancer in the NIH-AARP Diet and Health Study. American Journal of Clinical Nutrition, 2007; 85. 5:1353-1360.

17. Edwards BK, Ward E, Kohler BA, Eheman C, Zauber AG, Anderson RN, Jemal A, Schymura MJ, Lansdorp-Vogelaar I, Seeff LC, van Ballegooijen M, Goede SL, Ries LA. Annual report to the nation on the status of cancer, 1975-2006, featuring colorectal cancer trends and impact of interventions (risk factors, screening, and treatment) to reduce future rates. Cancer 2010;116(3):544-573.

18. Botteri E, Iodice S, Raimondi D, Maisonneuve P, Lowenfels AB. Smoking and Adenomatous Polyps: a Meta-analysis. Gastroenterology. 2008;134(2):388-395.e3

19. Hannan LM, Jacobds EJ, Thun MJ. The association between cigarette smoking and risk of colorectal cancer in a large prospective cohort from the United States. Cancer Epidemiology, Biomarkers & Prevention.2009;18(12):3362-3367.

20. Botteri E, Iodice S, Bagnard V, Raimondi S, Lowenfels AB, Maisonneuve P. Smoking and colorectal cancer: a meta-analysis. Journal of American Medical Association.2008;300(23):2765-2778.

21. American Institute for Cancer Research. Researchers present data linking obesity/overweight to higher cancer risk, poorer cancer survival. November 2009.

22. Cotterchio M, Boucher BA, Manno M, Gallinger S, Okey AB, Harper PA. Red meat intake, doneness, polymorphisms in genes that encode carcinogen-metabolizing enzymes, and colorectal cancer risk.Cancer Epidemiology, Biomarkers & Prevention. 2008;17:3098-3107.

23. Cheng J, Ogawa K, Kuriki K, Yokoyama Y, Kamiya T, Seno K. Increased intake of n-3 polyunsaturated fatty acids elevates the level of apoptosis in the normal sigmoid colon of patients polypectomized for adenomas/tumors. Cancer Letters, Volume 193, Issue 1,10 April 2003; 1: 17-24

24. “Vitamin D and Cancer Prevention.” National Institutes of Health. National Cancer Institute; 2013

25. “Dietary Supplement Fact Sheet: Vitamin D.” National Institutes of Health. Office of Dietary Supplements. 

26. Bassett, M. Are Antibiotics Linked to Early-Onset Colorectal Cancer?. Medpage Today. July 2021.

Can a handful of nuts a day keep cancer away?

By Krista Kleczewski, Claire Karlsson, and Edyth Dwyer

Evidence is growing about the many ways in which eating nuts, seeds, and legumes can improve your health. Eating walnuts or legumes like peanuts, beans, or lentils have been linked to healthier hearts and a lower risk of diabetes, but now studies show they may also cut your risk of getting cancer! Here’s what we know and don’t know.

In addition to erroneously thinking that peanuts are nuts, many people think almonds, cashews, and pecans as nuts, but they are actually types of seeds. The difference is based on the plant they grow on, where peanuts grow underground below the plant roots, nuts and seeds grow inside or outside the plant’s fruit. Although this article uses the term “nuts,” the studies we describe include many combinations of nuts, seeds, and legumes. It’s also important to note that each study has different methods, and they need to be interpreted differently. Some studies looked at fewer than 100 people and closely tracked their diet and health, while others were meta-analyses that collected results from many studies of thousands of people and summarized their findings. 

What are some health benefits of nuts?

 In 2015, a Dutch study of 120,000 men and women between the ages of 55-69 found that those who ate about half a handful of nuts or peanuts each day were less likely to die from respiratory disease, neurodegenerative diseases, diabetes, cardiovascular diseases, or cancer than those who consumed no nuts or seeds.[1] The same benefit was not seen for peanut butter, however, which suggests that the salt, vegetable oils, and trans fatty acids in peanut butter may counterbalance the benefits of the peanuts. A serving of nuts is about the size of 30 almonds, and a study found that eating several servings a week had health benefits. A 5-year study conducted in Spain of 7,000 men and women aged 55 to 80 years old found that eating at least three servings of nuts per week reduced the risk of cardiovascular and cancer death.[2] Another study similarly found eating nuts – especially walnuts — reduces the risk of developing cancers, diabetes and heart disease when eaten as a part of the Mediterranean Diet, which also emphasizes fruits, vegetables, whole grains, and legumes.[3] Walnuts were highlighted by the study as reducing inflammation associated with certain cancers and other conditions like diabetes and heart disease. More evidence is needed, however, to determine the specific impact of walnuts on cancer risk.

Breast Cancer

Eating large amounts of peanuts, walnuts, or almonds can reduce the risk of developing breast cancer, according to a 2015 study of 97 breast cancer patients.[4] The researchers compared the lifetime consumption of peanuts, walnuts and almonds among breast cancer patients with the consumption of those without breast cancer, finding that women who ate large quantities were half to one-third as likely to develop breast cancer. No difference was found between people who ate a small amount of nuts, legumes and seeds and those who ate none at all, suggesting that a person needs to consume a substantial amount of these over their lifetime to reduce their chances of developing breast cancer.

Another study looked at the risk of breast cancer for people who ate nuts and peanuts compared to people who did not. Some types of breast cancers respond to the body’s natural hormone estrogen, growing faster when exposed to estrogen. These are called Estrogen Receptor (ER) positive cancers. ER negative cancers are not influenced by exposure to estrogen. In a study of over 4,000 women in the Netherlands, those who ate 10 grams (a large handful) of nuts per day had a 45% lower risk of developing ER negative breast cancer when compared to those who ate no nuts, but it did not significantly affect ER positive breast cancer.[5,6] Since ER negative breast cancer occurs in only a third of the 12% of women who are diagnosed with breast cancer, the risk to the average person decreased overall by about half of 1% when their diet included that many nuts. 

Girls who regularly eat nuts in their diet may be less likely to develop breast cancer as adults. A 2020 study of more than 9,000 girls between the ages of 9-15, and found that girls who regularly ate peanut butter or any kind of nuts were 36% less likely than girls who did not to have developed benign breast conditions when followed up with 10 years later. Although not dangerous, benign breast conditions (such as breast cysts or hyperplasia) increase a woman’s chances of eventually getting breast cancer. [7]

Can eating nuts, legumes and seeds reduce colorectal cancer risk?

To find out whether snacking on foods with peanuts lowers your chances of getting colorectal cancer (also called colon cancer), researchers studied more than 23,000 adults in Taiwan, ages 30 and older.[8] The researchers reported in 2006 that women who ate meals with peanut products at least twice each week were less likely to develop colorectal cancer. More research is needed to see if this benefit is actually from the peanuts.

A 2021 meta-analysis collected results from over 40 studies, and it examined whether eating more nuts would have an impact on colon cancer risk. Researchers found that eating 5 grams of nuts per day could decrease the risk of colon cancer by 25%.[9] Since the lifetime risk of colon cancer is about 4%, a 25% reduction would mean a decrease from 4% to 3% of the overall risk of colon cancer for people regularly eating nuts. Five grams is about 5-6 almonds, and this study found that the benefits of eating nuts started for people averaging just 2 grams per day and continued to decrease for people eating up to 9 grams per day.  After that, the effects leveled off, so eating more than 9 grams was not more beneficial than eating 9 grams. A meta-analysis combines results from many studies, so the 2-9 grams per day were average amounts, whether the person eats them all in one day or spread out over the course of a week. 

In one of the largest studies of diet and cancer, which was conducted in 10 European countries, researchers discovered that eating nuts and seeds reduced women’s chances of developing colon cancer, but did not lower the risk for men.[10] Women who ate a modest daily amount of nuts and seeds (about 16 peanuts or a small handful of nuts or seeds) every day were less likely to develop colon cancer, and women who ate the largest quantities of these foods were the least likely to develop colon cancer. Again, more research is needed to understand these findings.

Researchers have also investigated whether a diet containing nuts and peanuts can improve patient chances of survival for those who have already been diagnosed with colon cancer. In a study of over 800 patients with advanced (stage III) colon cancer, patients who ate more nuts were more likely to survive after treatment, without being re-diagnosed with colon cancer.[11] This study measured a serving of nuts to be one ounce, or about 15 cashews. When compared to those who ate no nuts, those who ate 2 or more servings of nuts per week had 46% lower risk of re-diagnosis of their cancer, as well as a 53% lower risk of dying from the cancer. This study has several important limitations to keep in mind. Not only was it a relatively small study, but it only examined Stage III colon cancer patients, comparing cancer patients who ate nuts to those who did not eat nuts. This means that the results cannot be generalized to the average American’s risk of colon cancer. 

Pancreatic Cancer

Eating nuts also seems to lower the risk of developing diabetes, which may then lower the risk of developing pancreatic cancer.[12] In addition, a large study of women found that frequently eating nuts was associated with less chance of developing pancreatic cancer,13 one of the most deadly cancers.

A 2021 meta-analysis that examined results from over 30 studies, found that the chances of developing pancreatic cancer risk decreased for those who ate more nuts. The average lifetime risk of developing pancreatic cancer is about 1.5%. Because the results show a 6% lower risk for those eating nuts, this means the overall risk of pancreatic cancer may lower from 1.5% to 1.4% for people who regularly eat nuts.[9]

Ovarian cancer

A 2010 study examined the possible link between ovarian cancer and foods high in phytoestrogens and/or fiber, including nuts, beans, and soy.[15] They found that these foods seemed to help prevent “borderline ovarian cancer”—slow-growing tumors that are less dangerous and more likely to affect younger women. However, these foods did not seem to protect against the more aggressive types of ovarian cancer.

What makes nuts good for your health?

There is still some debate about why nuts might be so beneficial. Omega-3 fatty acids are found in peanuts, walnuts, and some seeds, and researchers think their health benefits may help to prevent cancer.[16] The omega-3 acids can help protect cell structures and walls, and since they are anti-inflammatory; that might reduce the risk of cancer for people who regularly eat peanuts, walnuts, and seeds. [17]

Some research has shown that walnuts can also improve your gut biome, meaning it helps you grow healthy bacteria in your gut.[18]  To test this, an experiment was done on 18 people, where some were assigned to eat walnuts and others ate no nuts. Blood and fecal samples were tested, and researchers were able to see changes in the bacteria, and lower levels of “secondary bile” which suggests the nuts decreased inflammation in their intestines. This experiment studied a very small group of people, so more research is needed to understand why these nuts, seeds, and legumes improve the risk of cancer over a lifetime. 


The Bottom Line

There is growing evidence that nuts, legumes, and seeds reduce the risk for several types of cancer, as well as having other health benefits. Researchers are still investigating whether the health benefits of nuts are because people who eat nuts have a healthier overall diet, but tree nuts seem to have some health benefits on their own. Peanuts and peanut butter may also have benefits, but the higher levels of fat and sodium could explain why these legume products show fewer health benefits. Peanuts, walnuts, almonds, and other nuts are high in calories, so don’t overdo it. It seems safe to assume that adding these foods to your diet, in small quantities several times a week, is a good idea, especially if you use them to replace less healthy snacks.




  1. Brandt, P., & Schouten, L. Relationship of tree nut, peanut and peanut butter intake with total and cause-specific mortality: A cohort study and meta-analysis. (2015). International Journal of Epidemiology, 44(3), 1038-1049. doi:10.1093/ije/dyv039  
  2. Guasch-Ferré, M., Bulló, M., Martínez-González, M.A., Ros, E., Corella, D., et al. Frequency of nut consumption and mortality risk in the PREDIMED nutrition intervention trial. (2013). BMC Med; 11: 164. doi: 10.1186/1741-7015-11-164  
  3. Toner, CD., Communicating clinical research to reduce cancer risk through diet: Walnuts as a case example (2014). Nutr Res Pract. 8(4): 347–351. doi: 10.4162/nrp.2014.8.4.347  
  4. Soriano-Hernandez, A.D., Madrigal-Perez D.G., Galvan-Salazar H.R., Arreola-Cruz A., Briseño-Gomez L., Guzmán-Esquivel J., Dobrovinskaya O., Lara-Esqueda A., Rodríguez-Sanchez I.P., Baltazar-Rodriguez L.M., Espinoza-Gomez F., Martinez-Fierro M.L., de-Leon-Zaragoza L., Olmedo-Buenrostro B.A., Delgado-Enciso I. (2015). The Protective Effect of Peanut, Walnut, and Almond Consumption on the Development of Breast Cancer. 2015;80(2):89-92. doi: 10.1159/000369997.  
  5. van den Brandt P.A., Nieuwenhuis L. Tree nut, peanut, and peanut butter intake and risk of postmenopausal breast cancer: The Netherlands Cohort Study. Cancer Causes Control, (2018). 29(1):63–75.
  6. Putti T.C., El-Rehim D.M.A., Rakha E.A., Paish C.E., Lee A.H.S., Pinder S.E., et al. Estrogen receptor-negative breast carcinomas: a review of morphology and immunophenotypical analysis. (2005). Mod Pathol, 18(1):26–35.
  7. Berkey C.S., Tamimi R.M., Willett W.C., Rosner B., Hickey M., Toriola A.T., et al. Adolescent alcohol, nuts, and fiber: combined effects on benign breast disease risk in young women. (2020). NPJ Breast Cancer;6(1):61.
  8. Yeh, C. C., You, S. L., Chen, C. J., & Sung, F. C. Peanut consumption and reduced risk of colorectal cancer in women: a prospective study in Taiwan. (2006). World Journal of Gastroenterology, 12(2), 222.  
  9. Naghshi, S., Sadeghian, M., Nasiri, M., Mobarak, S., Asadi, M., Sadeghi, O. Association of total nut, tree nut, peanut, and peanut butter consumption with cancer incidence and mortality: A comprehensive systematic review and dose-response meta-analysis of observational studies. (2021). Adv Nutr, 12(3):793–808.
  10. Jenab, M., Ferrari, P., Slimani, N., Norat, T., Casagrande, C., Overad, K., Riboli, E. et al. Association of nut and seed intake with colorectal cancer risk in the European Prospective Investigation into Cancer and Nutrition. (2004). Cancer Epidemiology Biomarkers & Prevention, 13(10), 1595-1603.  
  11. Fadelu T., Zhang S., Niedzwiecki D., Ye X., Saltz L.B., Mayer R.J., et al. Nut consumption and survival in patients with stage III colon cancer: Results from CALGB 89803 (alliance). (2018). J Clin Oncol,36(11):1112–20.
  12. Jenkins, D. J., Kendall, C. W., Banach, M. S., Srichaikul, K., Vidgen, E., Mitchell, S., Josse, R. G., et al. Nuts as a replacement for carbohydrates in the diabetic diet. (2011). Diabetes care, 34(8), 1706-1711.  
  13. Bao, Y., Hu, F. B., Giovannucci, E. L., Wolpin, B. M., Stampfer, M. J., Willett, W. C., & Fuchs, C. S. Nut consumption and risk of pancreatic cancer in women. (2013). British journal of cancer.  
  14. Lee J.T., Lai G.Y., Liao L.M., Subar A.F., Bertazzi P.A., Pesatori A.C., et al. Nut consumption and lung cancer risk: Results from two large observational studies. (2017). Cancer Epidemiol Biomarkers Prev,26(6):826–36.
  15. Hedelin, M., Löf, M., Andersson, T. M. L., Adlercreutz, H., & Weiderpass, E. Dietary phytoestrogens and the risk of ovarian cancer in the women’s lifestyle and health cohort study. (2011). Cancer Epidemiology Biomarkers & Prevention, 20(2), 308-317.  
  16. Fabian C.J., Kimler BF, Hursting S.D.. Omega-3 fatty acids for breast cancer prevention and survivorship. (2015) Breast Cancer Res;17(1):62.
  17. Freitas R.D.S., Campos M.M.. Protective effects of omega-3 fatty acids in cancer-related complications. (2019). Nutrients;11(5):945.,structure%20and%20fluidity%20of%20membranes
  18. Holscher H.D., Guetterman H.M., Swanson K.S., An R., Matthan N.R., Lichtenstein A.H., et al. Walnut consumption alters the gastrointestinal Microbiota, microbially derived secondary bile acids, and health markers in healthy adults: A randomized controlled trial. (2018). J Nutr;148(6):861–7.

Good news for coffee drinkers: the health benefits outweigh the risks for most people

By Morgan Wharton, Jessica Cote, and Shahmir Ali

latte-249102_640Most Americans drink coffee every day.1 The caffeine in coffee helps us stay alert but also may cause jitteriness and interfere with sleeping. A few studies suggest that decaffeinated coffee also has health benefits, perhaps because of antioxidants or acids in the coffee bean.2

What Are The Health Benefits Of Drinking Coffee?

For years medical experts advised people to drink less coffee, mostly because of research suggesting coffee might increase the risk of heart disease. However, numerous studies conducted recently have discovered coffee’s unexpected health benefits. Like all well-designed research, most of these studies considered the impact of age, sex, body mass index (BMI), physical activity, tobacco use, and whether family members had developed cancer. By controlling for those factors, researchers made sure they could separate coffee’s impact on health from the effects of people’s lifestyle, family history, and previous health problems. However, the type of coffee you drink may influence its health benefits; a very large study from the UK published in 2022 found that adults who drank larger quantities of unsweetened or sugar-sweetened coffee were less likely to die from cancer in the subsequent 7 years, and also less likely to die from any cause during that time frame.3  However, drinking more artificially sweetened coffee had no impact on cancer or other deaths.

Colorectal Cancer

Meta-analyses are a kind of statistics that combine data from several comparable studies to make one very large study. These results are usually more accurate than any one study can be. Taken together, three meta-analyses suggest that drinking about four or more cups of coffee per day may reduce the chances of getting colorectal cancer by 11-24%.456

Endometrial (uterine) Cancer

Using data from 67,470 women who participated in the Nurses’ Health Study, researchers found that women who drank four or more cups of coffee per day were 25% less likely to develop endometrial cancer than women who drank only one cup of coffee per day. Compared to women who did not drink any coffee, those who drank four cups or more per day were 30% less likely to develop endometrial cancer. Decaffeinated coffee was just as effective as caffeinated coffee, but caffeinated tea did not lower the risk of endometrial cancer.7

Liver Cancer And Cirrhosis (Scarring of the Liver/Chronic Liver Disease)

One study found people who drank one or two cups of coffee per day had a slightly lower risk of getting the most common type of liver cancer compared to non-drinkers, but people who drank three or four cups of coffee were about half as likely as non-drinkers to get this kind of liver cancer. Meanwhile, people who drank five or more cups per day had an even lower risk than that (about one-third the risk of non-drinkers).8

Similarly, a study in Japan found a 76% decrease in the risk of that type of liver cancer in people who drank at least five cups of coffee per day compared to those who did not drink coffee. The strongest benefit was seen in individuals with hepatitis C, a disease which increases a person’s risk of developing liver cancer, although the researchers were not sure why.9

A study of 120,000 Americans over an 8-year period found a 22% decrease in the chances of developing cirrhosis for each daily cup of coffee. In Norway, a 17-year study of 51,000 citizens found that those who drank two or more cups of coffee per day were 40% less likely to develop cirrhosis compared to those who did not consume coffee.10

Skin Cancer

Using data from two enormous studies, the Nurses’ Health Study and the Health Professionals Follow-up Study, researchers found that men and women who drank more than three cups of caffeinated coffee per month were 17% less likely to develop basal cell carcinoma compared to people who drank less than one cup per month. Basal cell carcinoma is the most common and least dangerous type of skin cancer. Drinking decaffeinated coffee did not affect basal cell carcinoma.11

A 2014 study in the Journal of the National Cancer Institute found that the more coffee participants drank, the less likely they were to develop malignant melanoma over a 10 year period. Melanoma is the most dangerous form of skin cancer. Almost 450,000 whites, aged 50-71, participated in the study. Researchers found that drinking four or more cups of coffee per day was linked to a 20% lower risk of getting malignant melanoma. Once again, drinkers of decaffeinated coffee lost out. Their risk of getting melanoma was no different from that of non-coffee drinkers. Coffee drinking, however, did not affect the least dangerous form of melanoma, called melanoma in situ.

Remember that no matter how much coffee with caffeine you drink, the best way to prevent skin cancer is still to limit your time exposed to the sun and ultraviolet light! 12

Type 2 Diabetes

People in Finland consume more coffee than almost any other nation, and a study of 14,000 people over 12 years  found that men who drank 10 or more cups of coffee daily had a 55% lower risk of developing type 2 diabetes than men who drank 2 cups of coffee a day or fewer.  Even more dramatic, women who drank 10 or more cups per day had a 79% lower risk of developing type 2 diabetes than those who drank fewer than 2 cups daily.13

A different Finnish study of 5,000 sets of identical twins found that individuals who drank more than seven cups of coffee per day had a 35% lower risk of type 2 diabetes than their twins who drank two cups or fewer per day.14 Because identical twins are so biologically similar, the difference in disease risk is very likely caused by coffee consumption levels. Studies of fewer people in other countries have found less dramatic but similarly positive results.

Parkinson’s Disease

A study of more than 8,000 Japanese-American men found that men who did not drink coffee at all were three to five times more likely to develop Parkinson’s disease within 30 years than men who drank four and a half cups or more of coffee per day.15


Because suicide may be related to alcohol intake, medications, and stress levels, suicide studies took those factors into account.  A 10-year study of 128,000 people in California found that the risk of suicide decreased by 13% for every additional cup of coffee consumed per day. Even one cup of coffee per day seemed to reduce the risk of suicide. A different 10-year study of 86,000 women found a 50% lower risk of suicide for those who drank two or more cups of coffee per day compared to women who did not drink coffee.16

Brain Power and Aging

A study of 676 healthy men born between 1900 and 1920 suggested that coffee helped with information processing and slowed the cognitive decline typical of aging. Cognitive functioning was measured by the Mini-Mental State Examination, a 30 point scale. Men who regularly consumed coffee experienced an average decline of 1.2 points over 10 years, while men who did not drink coffee saw a decline of 2.6 points over 10 years. Men who drank three cups of coffee per day declined only 0.6 points over 10 years.17

Even old mice are sharper with caffeine: a study using a mouse model of Alzheimer’s disease showed that coffee actually reversed the cognitive decline and slow-down in processing that occurred with age. Mice given caffeine in their water showed signs of recovering their memory during testing.18

What about the risks?


Two separate studies found that 300 mg of caffeine (two to three cups of coffee) decreased a woman’s chances of getting pregnant by more than a third. This same amount of coffee also increased the chances of women having low birth-weight babies by 50%. These studies took into account potentially influential  factors such as contraception used in the past and infertility history.19

Hip Fracture

According to data from the Nurses’ Health Study, women aged 65 and over who drank more than four cups of coffee per day had almost 3 times as many hip fractures over the next six years as women who did not drink coffee. Researchers took important factors into consideration such as how much calcium the women consumed each day.20

Parkinson’s Disease among post-menopausal women taking estrogen-only hormone therapy

Other researchers used data from the Nurses’ Health Study to evaluate the risk of Parkinson’s disease among women who drank coffee while using estrogen medication after menopause. For women who were NOT using estrogen therapy, those who drank four or more cups of coffee per day were about half as likely to develop Parkinson’s disease as women who did not drink coffee. For women who did use post-menopausal estrogen, however, those who drank four or more cups of coffee were about twice as likely as those who didn’t drink coffee to develop Parkinson’s.21

Heart Disease

Two different meta-analyses found that people who drank five or more cups of coffee per day were 40-60% more likely to develop heart disease compared to those who did not drink coffee at all. Other studies have also shown that high coffee use (five to ten cups per day) increases the risk of heart disease, while moderate consumption (three to four cups daily) was not associated with a higher risk. Only coffee drinkers who consumed more than nine cups a day had a greater risk of dying from heart disease.22 It is important to consider that people drinking close to 10 cups of coffee a day are likely to have other health problems, such as stress or sleep deprivation, and this could contribute to higher risk of heart disease and death regardless of coffee use.

Bottom line

For most people, drinking coffee seems to improve health more than harm it. Many of coffee’s health benefits increase with the number of cups per day, but even one cup a day lowers the risk of several diseases. However, women who want to get pregnant or already are pregnant and women over 65 should probably limit their coffee intake because, in their case, the risks may outweigh the health benefits.

Even though many studies show coffee has benefits, it’s still not clear why. How can one popular beverage help metabolism (for example, lowering the risk of type 2 diabetes) and also protect against a range of cancers? Until further research can solve that puzzle, most adults should continue to enjoy their cup (or two, or three) of Joe. Finally, remember that nearly all studies on coffee and health have been done on adults. Coffee may affect children and teens differently.

Have colon cancer? Skip the hot dogs, deli, and burgers

Caitlin Kennedy, Ph.D.

New research shows that eating red meat and processed meat increases the risk of colon cancer or of dying from colon cancer. The 2013 Cancer Prevention study by the American Cancer Society has been studying the impact of diet on cancer by following 184,000 patients for 18 years.23

Among the men and women diagnosed with colon cancer, those who ate more than 4 servings per week of red or processed meat before and after they were diagnosed with colon cancer were significantly more likely to die from colon cancer than those who ate fewer than 4 servings per week. Processed meats include deli foods such as hot dogs, sausage, bacon, and bologna, ham and other lunch meats, and bacon. Those who ate more than 4 servings per week had a 79% higher risk of dying from colon cancer compared to those who ate these foods less often. Those who had a family history of colon cancer and ate these foods frequently were especially likely to die from colon cancer.

Remember that “portion” sizes are smaller than what many people typically eat in a meal. For example, 2 hot dogs are considered 2 portions, and one double quarter pound hamburger is considered 3 portions. A large steak could be counted as 3 portions or even more.

Previous research has found connections between eating red meat frequently and an increased likelihood of being diagnosed with colon cancer and other health problems. However, this study is the first to show an increased risk of death from colon cancer.

Bottom line

These very popular foods are more harmful than any of us would like to think. The best way to prevent a variety of health problems, including colon cancer, is to limit red and processed meats in your diet. While the chicken or turkey you make in your oven is fine, the processed chicken and turkey sold at the deli counter or packaged in the supermarket are processed foods. Unfortunately, grilled foods including grilled chicken have also been associated with colon cancer.24 Fish and beans are other healthier sources of protein. If you have a family history of colon cancer, you should be especially careful to eat red and processed meats less frequently. Keep in mind that the American Cancer Society study found an increased chance of dying from colon cancer for men and women who ate these foods either before or after they were diagnosed with colon cancer.

The good news is that it’s never too late to start eating healthy and cutting back on your red and processed meat consumption! Even if someone is already diagnosed with colon cancer, eating less red meat and less processed meat can increase the chances of cancer survival.

Can Sleeping Pills Cause Cancer?

Brandel France de Bravo, MPH, Kousha Mohseni, MS, Cancer Prevention and Treatment Fund

When we hear “sleeping pills,” most of us think of prescription drugs such as Ambien (generic name zolpidem), Restoril (temazepam), and Lunesta (eszopiclone).  While prescription sleep medications are big business — more than $41 billion/year in the U.S. many people with trouble sleeping turn to over-the-counter antihistamines such as Tylenol PM and Benadryl.[1]  However, the use of these drugs may take a nosedive in light of the findings of a study published in the prestigious British Medical Journal. Led by researchers at the Scripps Clinic Viterbi Family Sleep Center in California, the study shows that people who take these drugs are significantly more likely to be diagnosed with cancer or to die within the next two and a half years than people who don’t take them. Author Dr. Daniel Kripke estimates that these popular sleep medications could cause 320,000 to 507,000 deaths in just one year.

The researchers looked at 10,529 primary care patients who were prescribed sleeping pills between 2002 and 2007 and compared the health of each of them to at least two very similar patients without such prescriptions who were the same sex, ethnicity, marital status, smoking status, and had similar health conditions, alcohol use and BMI (which measures if a person is overweight). The patients were followed for 2.5 years on average, and were from a Pennsylvania clinic that serves a mainly low-income population.

Sleeping Pills, Death, and Cancer

Patients who were prescribed sleeping pills were at least three to five times more likely to have died during the study than were the patients not prescribed sleeping pills. Even the patients who were prescribed fewer than 18 pills per year were at higher risk of dying: 3.6 times higher. Patients who were prescribed more than 132 pills a year were more than five times as likely to die.

The researchers were careful to exclude from the study patients who were diagnosed with cancer before the study or very early in the study. Heavy users of sleeping pills (over 132 pills prescribed per year) had a 35% greater risk than those with fewer pills prescribed.  Among those with prescriptions for sleeping pills, the increased risk of their developing lymphoma, lung cancer, colon and prostate cancer was greater than the risk from being a current smoker.

Before this study, there were at least 18 other studies showing an increased risk of death for people taking sleeping pills, and several also showed an increased risk of cancer.  However, this study is especially well-designed and the only one that includes the newer, short-acting class of popular sleeping pills known as nonbenzodiazepines. These were generally believed to be safer than previous generations of sleeping pills because they wear off more quickly. In fact, before this study it was believed that the worst side effect was weight gain due to night time raids on the refrigerator while sleep walking.

Among study participants, the most commonly prescribed sleeping pill was zolpidem (sold as Ambien, Edluar, or Zolpimist), followed by temazepam (a benzodiazepine sold as Restoril). However, prescriptions for the use of any sleep aid was associated with a significant increase in the risk of death, including eszopiclone (”Lunesta”), zaleplon (”Sonata”), barbiturates, as well as antihistamines such as diphenhydramine (the active ingredient in Benadryl), which is also used in many over-the-counter sleep aids. The average age of patients was 54, but the study found harm associated with sleeping pill use in every age group.[2]

All the sleeping pills showed a similar increased risk of death except Lunesta, which showed a more than 500% increased risk compared to any of the other sleeping pills.  However, Lunesta was a relatively new drug at the time of the study, and relatively few people took it. For that reason, it is not possible to say whether the risk of Lunesta is really that high.  Also important to note: This study did not evaluate cancer among patients taking Belsomra, a newer sleeping aid with numerous side effects.[3]

One shortcoming of the study is that getting a prescription for a sleeping pill is not the same as taking sleeping pills.  It is possible that some of the people with prescriptions, especially for small numbers of pills, never took any of them. It is also possible that people who did not have prescriptions for sleeping pills took Benadryl or other over-the-counter antihistamines to help them fall asleep, instead of the prescription version of the same pills.  However, those shortcomings would tend to underestimate the risk of sleeping pills, rather than overestimate the risks.

In addition to the major study cited above, there is other evidence linking sleeping pills to cancer.  For example, a study of Taiwanese patients published in 2012 found that Ambien promoted viral infections, which reflects a weakening of a person’s ability to fight off infections and diseases.[4]  That could explain the increased risk of cancer.

Also, a study published in the Korean Journal of Family Medicine in 2018 found that sleeping pills were strongly associated with esophageal, kidney, prostate, liver, stomach and pancreatic cancers. Of all the sleeping pills in the study, Ambien most strongly predicted a diagnosis of cancer.[5]

But Why?

What could possibly explain these increased risks?  Are people who are prescribed sleeping pills more anxious or stressed out? There is evidence that they are more likely to have car accidents or to fall down, probably because of the residual effects of the drugs during the day.  Other studies show an increase in infections among people taking sleeping pills, and that can also increase the risk of cancer and death from other causes. These other studies all suggest that sleeping pills really do increase the risk of dying and there are no logical explanations to explain away the substantial increased risks found in this study, especially the increased risk of cancer.

While the researchers can’t say for sure that the sleeping pills caused death or cancer, many people who used to take these medications should think about these new research findings and consider other, safer ways to fall asleep.  The sleep specialists who conducted the research suggest that since these sleeping pills have limited benefits, old-fashioned sleep aids like warm milk, as well as cognitive-behavioral approaches that can be taught and used for the rest of your life, would be excellent alternatives.  If you decide to toss your sleeping pills, be sure to see our article Drugs in the Drinking Water for tips on safe medicine disposal.

All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.


  1. Consumer Reports. Why Americans Can’t Sleep. Updated January 14, 2016. Accessed October 15, 2018.
  2. Kripke DF, Langer RD, Kline LE. Hypnotics’ association with mortality or cancer: a matched cohort studyBritish Medical JournalOpen 2012;2:e000850 doi:10.1136/bmjopen-2012-000850
  3. Kripke, D. F. (2015). Is suvorexant a better choice than alternative hypnotics? F1000Research4, 456.
  4. Kao, C.-H., Sun, L.-M., Liang, J.-A., Chang, S.-N., Sung, F.-C., & Muo, C.-H. (2012). Relationship of Zolpidem and Cancer Risk: A Taiwanese Population-Based Cohort Study. Mayo Clinic Proceedings87(5), 430–436.
  5. Kim, D.-H., Kim, H.-B., Kim, Y.-H., & Kim, J.-Y. (2018). Use of Hypnotics and Risk of Cancer: A Meta-Analysis of Observational Studies. Korean Journal of Family Medicine39(4), 211–218.

Colon Cancer Screening

Padma Ravichandran, Cancer Prevention and Treatment Fund

Colorectal Cancer (more commonly know as colon cancer) is cancer of the colon (large intestine) or rectum, both of which are part of the digestive system. The digestive system removes nutrients and minerals from the food we eat and beverages we drink, and uses them to help our body function. [1] The colon’s job is to remove water from the food that has been digested. The colon then passes the remains to the rectum, where they are eventually released from the body as fecal matter.[2]

In most cases, people with colon cancer don’t have any symptoms.[3]  However, possible symptoms of colon cancer include: blood in one’s stool, stomach aches and pains that do not go away, and weight loss that cannot be explained.  For information on how to prevent colon cancer, see “Colon Cancer: Who is at risk, and how can it be prevented?

Screening for colon cancer is especially important because when colon cancer is found in the early stages, patients do very well: 9 out of 10 people will be alive five years after their diagnosis and treatment.[4] Colon cancer develops from polyps, or abnormal growths in the colon. Not all polyps become cancerous, but all colon cancers develop from polyps. You can get polyps at any age, but they are more common as you get older.[5] Colon cancer screening checks for these polyps, but it does not show whether the polyp is cancerous or precancerous. The only way to know is to remove the polyp and analyze it.

Screening Methods

There are several methods for colon cancer screening. For a quick look at the advantages and disadvantages of each method, see the chart at the end of this article

There has been a gradual increase in screening rates over the last ten years but even so, only about half of the U.S. population at highest risk gets screened for colon cancer. Studies show that people who don’t get screened are less likely to be insured and less likely to have a primary care physician.  In addition, it is widely known that screening for colon cancer is not fun.  And, some people believe that they do not need to get screened because they are healthy. It is not unusual for a person to get a positive test result (indicating polyps or something that is not normal), but not return for the follow-up test.

While there are various ways to screen for colon cancer, a colonoscopy is usually performed when any of the screening tests show abnormal results and follow-up is necessary. A flexible tube with a tiny camera is used to look inside the colon (the whole colon) and to remove any polyps found. Colonoscopy is used for both screening and treating  which is why it has become the most widely used screening method. It is important to know that a study published in the February 2012 issue of the New England Journal of Medicine found that colonoscopies are even more effective at preventing deaths from colon cancer than previously thought-reducing deaths by more than half.[6]

Researchers in the study found that patients who received colonoscopies and had noncancerous or pre-cancerous growths (polyps) removed, were much less likely to die from colon cancer than people in the general population. People in the general population may not have been screened for colon cancer or may have used different, less effective screening methods. The researchers, who followed most patients for almost 16 years but followed some people for as long as 23, concluded that there was a 53% reduction in the death rate from colon cancer in patients who had colonoscopies and then had polyps removed.6 While the study does not establish whether colonoscopies are better than other screening methods in reducing deaths from colon cancer, it brings welcome news.

The results of the NEJM study reinforce the importance of prevention. The United States Preventive Services Task Force (USPSTF) and the Center for Disease Control and Prevention (CDC) recommend that everyone get screened for colon cancer using FOBT, sigmoidoscopy, or colonoscopy starting at age 50 and continuing until age 75. They do not recommend the Stool DNA Test or Computed Tomography Colonography (“Virtual Colonoscopy”) because there is not enough evidence about the risks and benefits of each of these methods.[7]

USPSTF Recommended Screening Methods

Fecal Occult Blood Test (FOBT)

There are two types of FOBT: the Guaiac and Immunochemical tests. They are both take-home tests that detect the presence of blood in stool. The patient is asked to use a brush or Q-tip like tool to obtain a sample of stool. At the doctor’s office or lab they will run the tests and check for blood or the chemical units that make up blood.[8]

Doctors check for blood because it can indicate that a polyp in the colon or rectum broke and started to bleed.[9]

The guaiac-based fecal occult blood test (gFOBT) uses the chemical guaiac to test for heme.  Heme is part of the protein hemoglobin that is in blood, and it contains the iron that our body uses.[10] To make sure that this test is accurate, you will have to avoid certain foods starting two days before providing the stool sample. You should eat a diet high in fiber, but avoid red meats, vitamin C, and foods that might irritate your digestive system. Unfortunately, the results often inaccurately show that there is blood in the stool when there isn’t, which is why more testing is needed afterwards.

The immunochemical fecal occult blood test (iFOBT) uses antibodies to find blood in the stool. Research shows that the iFOBT is more accurate at detecting blood than the gFOBT and it does not require you to limit what you eat. The drawback, however, is that it is also more expensive. The iFOBT can cost anywhere from $18-$40, while the gFOBT costs a few dollars. Most insurance providers will pay for this test and it is also covered under Medicare once a year.[11]

The CDC recommends getting a FOBT every year.[12] If you have a positive FOBT, meaning there is blood in your stool, then your doctor may recommend that you get a follow-up colonoscopy to check for polyps.


The sigmoidoscopy uses a lighted flexible tube (called a sigmoidoscope) with a tiny camera attached to examine the lower section of the colon and the rectum. The tube is inserted through the anus, up the rectum, and into the lower section of the colon. The procedure requires that the lowest part of the colon and rectum be clear of solids. In general, the doctor will prescribe a laxative and/or enema two hours before the procedure. The doctor may also ask the patient to restrict his or her diet to clear liquids for 1-3 days before the procedure.[13]

During the procedure, the doctor looks for inflamed tissue, abnormal growths and ulcers. Doctors can pass tools through the tube and remove any polyps or abnormal tissue. The growths can then be analyzed to determine if it is cancerous or not. Depending on the outcome of the test, the doctor may recommend getting a colonoscopy to check for polyps in the entire colon.

The sigmoidoscopy only lasts about twenty minutes, requires little preparation, and causes only mild discomfort. You may experience some cramping and bloating after the procedure but it usually only lasts about an hour. The drawback is that during the procedure there is a small chance of the colon or rectum tearing. Even though the procedure is less invasive than the colonoscopy, doctors are recommending the colonoscopy more often than the sigmoidoscopy.  Most doctors do not have the equipment for a sigmoidoscopy.  In addition the insurance reimbursement is less for the sigmoidoscopy than the colonoscopy.[14]

CDC recommends getting a sigmoidoscopy every five years. If the doctor finds polyps during the procedure he or she may recommend that you get a follow up colonoscopy.


 A colonoscopy is essentially a more comprehensive version of the sigmoidoscopy. The colonoscopy examines the entire colon and rectum using a longer lighted tube called a colonoscope. Similar to the sigmoidoscopy, the patients must clear their colon of solids before undergoing the procedure. The difference is that the colonoscopy requires that the entire colon be cleared, which requires more preparation. The doctor may tell you to go on a clear liquid diet 1-3 days before the procedure. In addition, your doctor will prescribe a laxative, and/or enema the night before the procedure. The laxative can be taken in pill or powder form. The powder form must be dissolved in water and is unpleasant. No matter the method of colon cleansing, the patient will need to use the bathroom several times, usually over several hours.

Because this procedure is so invasive, going even farther into the colon, you will be given anesthesia or some other sedative. Any time you are given anesthesia or medicine to make you less awake or sleepy, there is an added risk.[15] The colonoscope is inserted into the anus, up through the rectum, and into the colon. The doctor can check for inflamed tissue, ulcers, and abnormal growths and remove them if necessary. The removed tissue will then be analyzed to check if it is cancerous or not. The colonoscopy is usually recommended as a screening tool and a follow-up tool. This means that the procedure can be used to initially check for abnormal tissue, or it can be used when any of the other test results are positive for the presence of polyps.[16]

The procedures and recovery time for the colonoscopy is a little longer than the sigmoidoscopy. After the procedure, you will have to wait in the clinic for 1-2 hours until the sedative wears off. You will also need to make arrangements for someone to pick you up, because the doctor will not allow you to drive or take a taxi. As with the sigmoidoscopy, you may also experience cramping or bloating.

Due to how comprehensive and invasive the procedure is, the CDC recommends that you undergo a colonoscopy every 10 years. If they do find polyps during the procedure, they may ask you to repeat the procedure in less than 10 years.

Other Screening Methods

Stool DNA Test

The Stool DNA Test checks for any abnormal cells in the stool. For this test you need to collect an entire bowel movement, which may be unpleasant for some people, and send it in to the lab. There, they will look for certain DNA markers that indicate the presence of cancerous cells. Researchers have found that the Stool DNA Test is not very accurate or reliable. Its ability to detect colon cancer ranges from 20-71% so it is not cost effective to get this test.

Double Contrast Barium Enema (DCBE)

The DCBE uses x-rays and the metallic element Barium to examine the colon. They first clean out the colon and rectum using an enema that contains a solution with Barium. The Barium outlines the colon and rectum so it is more visible in the x-ray. There, doctors will be able to see any polyps or cancerous lesions.

The DCBE is effective at detecting certain growths, but often misses smaller polyps that may become cancerous. In most cases, the cancers that are found during the DCBE can also be found with a colonoscopy. Another concern is the amount of radiation you are exposed to during the procedure.  The DCBE has more exposure to radiation than the CT Colonography, which may lead to other adverse health problems.

Computed Tomography Colonography (CT Colonography)

CT Colonography-often called “Virtual Colonoscopy”-uses x-rays to create detailed visual images of the entire colon and rectum. However, in order to get good x-ray images, the colon and rectum must be cleared of solids by way of a clear liquid diet, enema, and/or laxative. As mentioned above, the laxative may be taken in pill or powder form. The powder form must be dissolved in water and is unpleasant. No matter the method of colon cleansing, the patient will need to use the bathroom several times, usually over several hours.

Once the x-ray images have been taken, a computer is used to assemble the pictures together to create a detailed picture of your colon and rectum. If the picture shows polyps or other abnormalities, a regular colonoscopy will be needed immediately to remove them.

Patients tend to prefer the CT Colonography because it is less invasive and causes less discomfort. This method is effective at identifying abnormal growths, but is not effective at identifying abnormal lesions that are flat or depressed. Another concern with the CT Colonography is exposure to radiation from the x-rays, which can increase your risk of getting cancer in the future even as it helps diagnose whether you have cancer currently.  Since the need to clear colon and rectum of solids with a laxative or enema is generally considered the worst part of a colonoscopy, the small advantages of the CT Colonography probably does not outweigh the decrease in accuracy and increase in radiation.






·  Preparation for the test is minimal

·  Sample can be collected at home

·  Very inexpensive

·  Getting “false-positive” results is common (you may be told you have a problem or something abnormal when you don’t).

·  Does not effectively detect all polyps and cancers

·  You must avoid certain foods for a  few days before collecting stool sample

·  Positive results may require additional tests, such as colonoscopy


·  Quick procedure with minimal discomfort

·  Doctor can remove polyps during procedure

·  Only requires that the lowest part of the colon be clear

·  Does not examine the entire colon—only the lowest part of the colon and the rectum

·  Small risk of bleeding or tearing in colon

·  Positive results may require additional tests, such as colonoscopy


·  Doctor can view entire colon and rectum whereas sigmoidoscopy only looks at lower colon

·  Doctor can remove polyps during procedure

·  Is one of the most sensitive colon cancer screening tests available

·  May not find all polyps or growths

·  Preparation involves clearing entire colon through clear liquid diet and/or enema

·  Patient sedated during procedure

·  Procedure time varies depending on how many polyps are found

·  Patient must be picked up or driven home by someone else afterwards

·  Small risk of bleeding or tearing in colon

 Stool DNA Test

·  Preparation for the test is minimal

·  Not invasive, so no risk of bleeding or tearing

·   Must provide entire bowel movement for testing

·  Not always accurate or reliable

 Double Contrast Barium Enema

·  Doctor can view entire colon and rectum

·  Complications rare

·  No sedation necessary

·  May not find all polyps or growths

·  Preparation involves thorough cleansing of entire colon through clear liquid diet, enema, and/or laxatives

·  “False-positive” results possible

·  Doctor cannot remove polyps during procedure

·  Positive results may require colonoscopy or other additional procedures

 CT Colonography


 “Virtual  Colonoscopy”

·  Doctor can view entire colon and rectum

·  Not invasive, so no risk of bleeding or tearing

·  May not find all polyps or growths

·  Preparation involves thorough cleansing of entire colon through clear liquid diet, enema, and/or laxatives

·  You will be exposed to some radiation (see “Everything You Ever Wanted to Know About Cancer and Radiation but Were Afraid to Ask”)

·  Positive results will require follow-up colonoscopy; recommended immediately after virtual procedure to avoid a second appointment and to biopsy lesions quickly



  1. National Cancer Institute. Colorectal cancer PDQ: General information about colorectal cancer. 2009.   Retrieved 22 Feb 2010 from the National Cancer Institute Web Site:
  2. National Institute of Health and National Library of Medicine. 2008. Large intestine. Retrieved on 24 Feb 2010 from the  MedLine Web Site:
  3. Center for Disease Control and Prevention. 2009. Colorectal cancer: Screening saves lives. Retrieved on 23 Feb 2010 from the Center for Disease Control and Prevention Web Site:
  4. Center for Disease Control and Prevention. Colorectal cancer screening rates. 2010. Retrieved on 24 Feb 2010 from the Center for Disease Control and Prevention Web Site:
  5. National Cancer Institute. Dictionary of cancer terms: Adenoma. 2009. Retrieved on 24 Feb 2010 from the National Cancer Institute Web Site:
  6. Zauber AG, Winawer SJ, O’Brien M.J, Lansdorp-Vogelaar I, van Ballegooijen M, Hankey BF, et al.  Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths.  New  England Journal of Medicine.2012; 366(8), 687-696.
  7. United States Preventive Services Task Force. Screening for colorectal cancer. 2008. Retrieved on 18 Feb 2010 from the Agency for Healthcare Research and Quality Web Site:
  8. Center for Disease Control and Prevention. Colorectal cancer screening basic fact sheet. 2009. Retrieved on 23 Feb 2010 from the Center for Disease Control and Prevention Web Site:
  9. Chen, JH and Lin, HH. Colorectal cancer screening. Tzu Chi Medical Journal. 2009; 21 (3), 190-196.
  10. National Cancer Institute. Colorectal cancer screening. 2009. Retrieved on 18 Feb 2010 from the National Cancer Institute Web Site:
  11. Levi, Z, Rozen, P, Hazazi, R.  A quantitative immunochemical fecal occult blood test for colorectal neoplasia. Annotated Internal Medicine. 2007; 146, 244-255.
  12. Center for Disease Control and Prevention.Colorectal cancer screening tests. 2010. Retrieved on 22 Feb 2010 from the Center for Disease Control and Prevention Web Site:
  13. National Institute of Health. Flexible sigmoidoscopy. 2008. Retrieved on 24 Feb 2010 from the National Digestive Diseases Information Clearinghouse Web Site:
  14. Klabunde, CN, Lanier, D, Nadel, M, McLeod, C, Yuan, G, Vernon, SW. Colorectal cancer screening by primary care physicians: Recommendations and practices 2006-2007. American Journal of Preventive Medicine. 2009; 37 (1), 8-16.
  15. National Institute of Health. Colonoscopy. 2010. Retrieved on 24 Feb 2010 from the National Digestive Diseases Information Clearinghouse Web Site:
  16. Neri, E, Faggioni, L, Cerri, F, Turini, F, Angeli, S, Cini L, Perrone, F, Paolicchi, F, Bartolozze, C.  CT colonography versus double-contrast barium enema for screening of colorectal cancer: comparison of radiation burden. Abdominal Imaging. 2009.