Category Archives: Diet, Habits, & Other Behaviors

Ways to Help Prevent Breast Cancer

February 22, 2017Breast Cancer, Diet, Habits, & Other Behaviors, PreventionCPTFeditor

Brandel France de Bravo, MPH and Diana Zuckerman, Ph.D., Cancer Prevention and Treatment Fund

Here’s the good news about how to cut your risk.

1. Lose weight (Diet and Exercise)

Numerous studies show that overweight and obese women are more likely to develop breast cancer.¹ Estrogen, a female hormone, provides nutrition for most breast cancers. The more fat cells you have, the more estrogen you have circulating in your body. Maintaining a healthy weight is like telling breast cancer cells that the restaurant is closed for business! The healthiest way to lose weight and to keep your weight down is to reduce the number of calories you eat and also to exercise. Exercise helps prevent breast cancer and also helps women who were diagnosed with breast cancer live longer.² You don’t need to become a Serena Williams or Brittney Griner. You just need to move! Walk at least part of the way to work, take the stairs instead of the elevator and pump iron (or choose the exercise of your choice) while you’re on the phone.

2. Avoid unnecessary hormones

Hormone therapy increases your risk of breast cancer, so avoid it if you can. If you’re taking hormone therapy, use it at the lowest possible dose for the shortest time – or just get off it as soon as possible. Also reduce your exposure to chemicals that act like hormones. Bisphenol A (BPA) is a chemical used in clear, hard plastic and in the linings of canned foods, canned drinks, disposable cutlery and many other common items, including baby bottles. BPA, phthalates (“Thah-lates”) and other chemicals known as “endocrine disruptors” appear to increase the risk of obesity, diabetes, early puberty in girls, and possibly the risk of breast cancer and prostate cancer. Here are some tips to limit your exposure to BPA:

Use frozen or fresh vegetables and fruits instead of canned. Get rid of older canned goods, especially if they contain tomatoes and other acidic fruits since the acid accelerates the leaching of BPA from can linings into the food. If you buy tomato or pasta sauce, look for brands sold in glass jars. Eden was one of the first brands to eliminate BPA in the linings of its canned foods, all of which have been BPA-free since 2016. Trader Joe’s, Amy’s, and several other less well-known brands offer some BPA-free canned products, such as beans and corn, but not soups and tomato-based canned foods.³

Look for drinks sold in glass, plastic bottles (soft plastic bottles like the ones typically used for soft drinks and water don’t have BPA), or cartons like those used for milk. Some of the glass bottles have tops lined with BPA but at least the top is not in constant contact with the beverage. If you carry a reusable water bottle, switch to stainless steel or look for the newer BPA-free sports bottles.

Switch to glass, porcelain, or stainless steel containers for hot foods and drinks because the heat is more likely to break down the BPA in the plastic and introduce it into your food or beverage.

When you microwave, use glass or ceramic, stoneware, or bone china containers. You can use any kind of non-plastic dishes and bowls as long as they don’t have gold or silver trim. If you need to cover the food to keep it from splattering in the microwave, use another dish or paper towel. Don’t microwave food or beverages in plastic or disposable containers (not even the ones they are sold in), and don’t cover dishes with plastic wrap in the microwave oven. Plastics that contain BPA are usually very hard and may have a triangle on the bottom with “7” inside or may say “PC.” Not all plastics with a Number 7 contain BPA, but all plastics break down when exposed to heat-whether in the microwave or the dishwasher-and strong soaps.

Phthalates, another endocrine disrupting chemical, have been linked to genital abnormalities in boys and men, and to early puberty in girls. Very large studies have tended to find that phthalate exposure slightly increases the chance of developing breast cancer⁴ and smaller studies have not⁵. Phthalates are used to soften plastics and add fragrance to personal care products like lotions, shampoos, and make-up. When they aren’t used as part of the fragrance, they are sometimes used to mask the natural smell of the chemicals in a product. Phthalates are everywhere-except on a product’s label. Phthalates are almost never listed as an ingredient if their use is related to the way a product does or doesn’t smell. Although the research results are not consistent, we conclude that more exposure to phthalates probably slightly increases a woman’s chance of developing breast cancer (by less than 1%). We do not know how the cumulative exposure to phthalates, PFAS, and other hormone-disrupting chemicals could increase the likelihood of developing cancer. You can minimize your exposure to phthalates by using shampoos, hair spray, deodorants, lotions, perfumes, make-up and nail polish that are phthalate free. If the product doesn’t state “phthalate-free” (and most don’t), you can visit the Environmental Working Group’s (EWG) Skin Deep Database or their Guide to Safer Cleaning Products to check the safety of your favorite personal care and household products. If you are not sure if a product has phthalates, choose the version that says “fragrance-free.”

3. Reduce stress

Reduce stress through regular exercise, meditation, or engaging in hobbies or activities that relax and fulfill you. You’ll never be able to eliminate stress from your life but you can learn to manage it better. If for you de-stressing includes watching television or “screen time,” try not to eat while doing it as people tend to eat more when they’re focused on something other than the food in front of them. If you’re going to snack, choose low-fat, nutrition-dense foods like fruits and low-fat yogurt or cheese and unsalted nuts.

4. Eat the right foods

Some foods have been shown to increase your risk of breast cancer and others appear to help prevent breast cancer (or breast cancer recurrence). Eating more than 3-4 portions of red meat like beef, pork and lamb can increase your risk of several cancers, including breast cancer. So, try to eat those meats less often, and smaller portions. Several studies have found that women who eat lots of fresh fruits and vegetables are at lower risk of breast cancer or breast cancerrecurrence. A study of post-menopausal women who ate a Mediterranean diet (lots of fresh fruits and vegetables, fish, and olive oil) also found a decrease in breast cancer, especially for women who supplemented their Mediterranean diet with more extra virgin olive oil.⁶ And a study of premenopausal women found that those who ate a lot fruits and vegetables with carotenoids in them had a lower risk of developing breast cancer. Carotenoid-rich foods are leafy greens like kale, spinach and collard greens and foods that are orange, red and sometimes yellow. They include: carrots, mangoes, apricots, squash, sweet potatoes, and tomatoes. And if you don’t like your veggies plain, you can add cayenne pepper or chili pepper for an extra dose of carotenoid!

5. Breastfeeding protects

If you are planning to have a child or add to your family, strongly consider breast feeding. Not only is breast milk good food for your baby, but the more you breast feed, the lower your risk of various cancers, including breast cancer. This is especially important if you got a late start on having a family, because delayed childbearing increases your breast cancer risk slightly—unless you have one of the BRCA breast cancer gene mutations. If you have BRCA1 or BRCA2, having children late in life or having no children at all does NOT add to your already elevated risk of breast cancer. Breastfeeding may lower the risk of breast cancer for women with BRCA1, but not for women with BRCA2. To read more about BRCA mutations and breast cancer risk, click here. http://www.ncbi.nlm.nih.gov/pubmed/12133652

6. Don’t smoke (or quit, if you do)

A United Kingdom study involving over 100, 000 women found a significant link between smoking and breast cancer. Over a 7-year period, about 2% of women who ever smoked developed cancer compared to about 1.6% of women who never smoked.⁷This means that smoking causes about 4 in 1000 breast cancers. Even though that number seems small (less than half a percent), it is statistically significant. Starting smoking at a younger age, smoking 15 or more daily cigarettes, and smoking for at least 10 years increase the chances of developing breast cancer. If you smoke, you should talk to your doctor about ways to quit. Quitting decreases the chances of developing breast cancer, but it may take about 20 years to see the full benefits. To read more, click here.

7. Do not drink more than 1 alcoholic beverage/day

Drinking alcohol increases your chances of developing several types of cancer, including breast cancer. The risks are greatest in those with heavy and long-term alcohol use, but even moderate drinking can add up over a lifetime. The CDC recommends that Americans can reduce their risk of alcohol-related health problems by drinking in moderation, which usually means 1 drink per day or less for women and 2 drinks per day or less for men. However, some studies recommend no more than 3 drinks per week for women.

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

1 Neuhouser ML, Aragaki AK, Prentice RL, et al. Overweight, Obesity, and Postmenopausal Invasive Breast Cancer Risk: A Secondary Analysis of the Women’s Health Initiative Randomized Clinical Trials. JAMA Oncol. 2015;1(5):611-621. doi:10.1001/jamaoncol.2015.1546

2 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

3 https://nutrineat.com/top-bpa-free-canned-food-brands?utm_source#google_vignette

4 Tang L, Wang Y, Yan W, et al. Exposure to di-2-ethylhexyl phthalate and breast neoplasm incidence: A cohort study. Sci Total Environ. 2024;926:171819. doi:10.1016/j.scitotenv.2024.171819

5 Reeves KW, Díaz Santana M, Manson JE, et al. Urinary Phthalate Biomarker Concentrations and Postmenopausal Breast Cancer Risk. J Natl Cancer Inst. 2019;111(10):1059-1067. doi:10.1093/jnci/djz002

6 Toledo E, Salas-Salvadó J, Donat-Vargas C, et al. Mediterranean Diet and Invasive Breast Cancer Risk Among Women at High Cardiovascular Risk in the PREDIMED Trial: A Randomized Clinical Trial [published correction appears in JAMA Intern Med. 2018 Dec 1;178(12):1731-1732. doi: 10.1001/jamainternmed.2018.6460]. JAMA Intern Med. 2015;175(11):1752-1760. doi:10.1001/jamainternmed.2015.4838

7 Jones ME. et al. Smoking and risk of breast cancer in the Generations Study cohort. Breast Cancer Research. 2017;19:118. https://doi.org/10.1186/s13058-017-0908-4

MyPlate: A New Alternative to the Food Pyramid

June 13, 2016Diet, Habits, & Other BehaviorsCPTFadmin

Caroline Novas, Cancer Prevention and Treatment Fund

A goal of the U.S. government is to help guide adults and children to be as healthy as possible. “MyPlate” replaces the familiar “food pyramid” diagram that underwent several changes in the 19 years since it was first introduced.^[1] The MyPlate model shows the five food groups (fruits, vegetables, proteins, grains, and dairy) in a place setting. It is designed to be easier to understand when you think about what types of food to include in each meal that you eat.

How Does MyPlate Work?

The plate is divided into four unequal sections to represent different food groups. Vegetables make up the largest section, followed by grains. Fruits and vegetables fill half the plate while proteins and grains fill the other half.

One of the most noticeable things about MyPlate is that it includes no distinct meat section. Instead, “protein” includes fish, shellfish, eggs, beans, peas, nuts, and seeds in addition to meat. In addition to recognizing the benefits of a plant-based diet, another big change is the elimination of the “oils” or “fats” section included in the food pyramid.

A small blue circle on the side of the plate represents dairy. This simple model is designed to make it easy for consumers to see what an ideal meal should look like, without too many restrictive details.

Critics of MyPlate say it shouldn’t include dairy, which they argue is unnecessary for a healthy diet. Critics also say it is important to give information about the size of the plate.

History: From MyPyramid to MyPlate

For over 100 years, the U.S. Department of Agriculture (USDA) has provided Americans with different types of food guides and pyramids to encourage healthy food choices. Since 1992, the Food Pyramid has been the dominant model. The idea behind the original 1992 Food Pyramid was that the foods we should eat most are the ones that form the base of the pyramid, while those we should eat less of are near the top. However, these guidelines were unclear and difficult to follow. The Food Pyramid was based on servings, but there was no clear guidance about serving size, and no guidance on the total number of calories recommended per day.

Because of these problems a new pyramid – MyPyramid — was introduced in 2005. Food groups were coded by stripes in widths corresponding to the recommended servings from each group. All the stripes tapered toward the top of the pyramid to remind people that each food group includes both healthy and unhealthy choices, such as foods with added sugar or “solid” fat. Although an improvement over the old Food Pyramid, MyPyramid was criticized as confusing to many consumers. The USDA hopes that MyPlate will provide a simple, easy to understand visual method for consumers to eat healthfully.

How Do I Plan Family Meals with MyPlate?

MyPlate is based on the 2015-2020 Dietary Guidelines for Americans, which provides detailed instructions for planning healthy meals and snacks. These guidelines are fairly long, but there are some simple points to take away:

Make half your plate fruits and vegetables. Try to choose whole or cut-up fruits without added sugars, and vary your vegetables; try different types and cooking them different ways (raw, steamed, roasted, sauteed) but try to avoid fried.
Switch to 1% or skim milk, cheese, and other dairy options. Avoid full-fat dairy products.
Half of your grains should be whole grains. Grains are the largest portion of MyPlate, and half of those should be whole grains. Look on labels for the word “whole”– not multigrain or seven grain. Brown rice and whole wheat pasta also count. Try to stay away from grain-based desserts and snacks, such as baked goods
Vary your protein. Try different types, such as seafood, eggs, beans, unsalted nuts, lean meat and poultry.
Watch out for sodium, saturated fat, and added sugars. Use nutrition labels to help you choose food and drinks that contain less sodium, fat and added sugar. Bread can have as much salt as salty snacks, for example. Many fruit juices have little fruit and lots of sugar, and sweetened coffee drinks can contain a lot of sugar and fat. Try to drink water instead of sugary drinks.
Get more physical activity. Most Americans don’t get enough physical activity. Daily exercise is important to overall health. Kids, especially, should have limited “screen time,” and be encouraged to play outdoors rather than watching TV or using the computer.

For more guidance, the USDA offers the ChooseMyPlate.gov website. You can use the website’s SuperTracker tool to create a personalized plan just for you. It also has other resources to help you find healthy recipes, calculate your BMI (body mass index), and learn more about how to maintain a healthy diet.

MyPlate information is also available in 20 different languages, including Spanish.

MyPlate can be a helpful basic guideline for kids and adults to know how much to eat from each food group, but it’s important to also follow the additional guidelines above for healthy eating.

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

ChooseMyPlate.gov. Retrieved June 7, 2011, from United States Department of Agriculture. http://www.choosemyplate.gov/index.html

Stomach Cancer and Diet: Can Certain Foods Increase Your Risk?

May 5, 2016Diet, Habits, & Other Behaviors, Other Cancers, PreventionCPTFeditor

Laura Gottschalk, PhD, Cancer Prevention & Treatment Fund

There is growing evidence that the foods we eat can increase the chances of developing certain types of cancer. A report by the World Cancer Research Fund International says that stomach cancer is one of them.

Stomach cancer is the fifth most common cancer worldwide and the third most common cause of death from cancer.[1] Older adults are more at risk to develop stomach cancer with most people in the U.S. being diagnosed over the age of 70.[2] Men are twice as likely to develop stomach cancer compared to women.[2]

You can’t control how old you are or whether you are a man or woman, but what you eat can either increase or decrease your chances of developing stomach cancer. The World Cancer Research Fund looked at all the scientific research that was available discussing diet, weight, physical activity, and the risk of stomach cancer.[3] After looking at 89 studies that examined nearly 77,000 cases of stomach cancer, the report concluded that each of the following can increase a person’s risk for developing stomach cancer.

Drinking three or more alcoholic drinks per day.
Eating foods preserved by salting, such as pickled vegetables and salted or dried fish, as traditionally prepared in East Asia.
Eating processed meats that have been preserved by smoking, curing or salting, or by the addition of preservatives. Examples: ham, bacon, pastrami, salami, hot dogs, and some sausages
Being overweight or obese, as measured by body mass index (BMI).

Based on their findings, the WCFR has made several recommendations to reduce your risk of stomach cancer:

Maintain a healthy weight
Be physically active
Eat a healthy diet that avoids processed meat and limits salt
Limit your alcohol consumption

These recommendations are good ones for preventing cancer in general, not just stomach cancer.

Still not convinced to give up your 6-packs, kimchi, and bacon just yet? This is just the latest of many studies showing that being overweight and eating processed meats increases your risk of cancer. And, previous research has also shown that drinking more alcohol increases your chances of developing cancer.[4] However, this is probably the most comprehensive study showing the link between a range of eating and drinking habits and stomach cancer.

In addition to what you eat, there are other aspects of your life that increase the risk of stomach cancer.

Smoking: It is estimated that 11% of stomach cancer cases are due to smoking.
Infection: A bacteria called pylori is known to cause chronic inflammation of the stomach which can lead to stomach cancer. Fortunately, food sanitation in developed countries dramatically cuts down on risk of infection.
Industrial chemicals: Exposure to dust and high-temperature environments in the workplace increases the risk of stomach cancer.

If you can’t reduce the risks of smoking, infection or industrial chemicals, changing your diet is the best option for reducing your chances of stomach cancer. Eating fresh vegetables and meats is better than preserved and processed ones. That doesn’t mean you should never eat another hot dog or slice of bacon, but it does mean trying to eat them only rarely. As with most things, moderation is key. Try and balance your diet: don’t just decrease the amount of unhealthy foods you eat, but also increase the amount of healthy foods. Studies have shown that eating lots of fresh fruits and vegetables, especially citrus fruit,[5] may even reduce your chances of developing stomach cancer![3]

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

References

end Centers for Disease Control and Prevention. “Global Cancer Statistics.” Department of Health and Human Services. 02 Feb. 2015. Accessed: 05/04/2016. http://www.cdc.gov/cancer/international/statistics.htm
end National Cancer Institute. “What you need to know about stomach cancer.” NIH Publication No. 09-1554. Printed September 2009. Brochure.
end World Cancer Research Fund International/American Institute for Cancer Research. Continuous “Update Project Report: Diet, Nutrition, Physical Activity and Stomach Cancer.” 2016. Available at: wcrf.org/stomach-cancer-2016.
end IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. “Personal habits and indoor combustions. Volume 100 E. A review of human carcinogens. Exit Disclaimer.” IARC Monographs on the Evaluation of Carcinogenic Risks in Humans. 2012: 100(Pt E):373-472.
end Bae JM, Lee EJ, et al. “Citrus fruit intake and stomach cancer risk: a quantitative systematic review.” Gastric Cancer. 2008;11(1):23-32.

Are E-Cigarettes Safer Than Regular Cigarettes?

April 11, 2016Diet, Habits, & Other Behaviors, Environmental Exposures, Lung Cancer, Prevention, UncategorizedCPTFeditor

Brandel France De Bravo, MPH, Sarah Miller, Jessica Becker, and Laura Gottschalk, PhD, Cancer Prevention & Treatment Fund

Electronic cigarettes, or e-cigarettes, are being marketed as the “safe” new alternative to conventional cigarettes. But are e-cigarettes safe? What does the FDA think about them? Are e-cigarettes going to reverse the decline in smoking—giving new life to an old habit—or can they help people quit smoking? Here is what you need to know before picking up an e-cigarette.

What Are E-Cigarettes?

Electronic cigarettes (e-cigarettes) are battery operated devices that used to be shaped like cigarettes but are now sometimes shaped to look like a flash drive, toy, or candy. They contain nicotine, which is an addictive drug that is naturally found in tobacco. Nicotine is what makes regular cigarettes addictive and e-cigarettes also allow nicotine to be inhaled, but they work by heating a liquid cartridge containing nicotine, flavors, and other chemicals into a vapor. Because e-cigarettes heat a liquid instead of tobacco, what is released is considered smokeless.[1]

Are E-Cigarettes Safer Than Traditional Cigarettes?

The key difference between traditional cigarettes and e-cigarettes is that e-cigarettes don’t contain tobacco. But, it isn’t just the tobacco in cigarettes that causes cancer. Traditional cigarettes contain a laundry list of chemicals that are proven harmful, and e-cigarettes have some of these same chemicals.

Since 2009, FDA has pointed out that e-cigarettes contain “detectable levels of known carcinogens and toxic chemicals to which users could be exposed.”[2] For example, in e-cigarette cartridges marketed as “tobacco-free,” the FDA detected a toxic compound found in antifreeze, tobacco-specific compounds that have been shown to cause cancer in humans, and other toxic tobacco-specific impurities.[3] Another study looked at 42 of these liquid cartridges and determined that they contained formaldehyde, a chemical known to cause cancer in humans.[4] Formaldehyde was found in several of the cartridges at levels much higher than the maximum EPA recommends for humans.

The body’s reaction to many of the chemicals in traditional cigarette smoke causes long-lasting inflammation, which in turn leads to chronic diseases like bronchitis, emphysema, and heart disease.[5f] Since e-cigarettes also contain many of the same toxic chemicals, there is no reason to believe that they will significantly reduce the risks for these diseases.

There are no long-term studies to back up claims that the vapor from e-cigarettes is less harmful than conventional smoke. Cancer takes years to develop, and e-cigarettes were only very recently introduced to the United States. It is almost impossible to determine if a product increases a person’s risk of cancer or not until the product has been around for at least 15-20 years. Despite positive reviews from e-cigarette users who enjoy being able to smoke them where regular cigarettes are prohibited, very little is known about their safety and long-term health effects.

Can E-Cigarettes Be Used to Cut down or Quit Smoking Regular Cigarettes?

If a company makes a claim that its product can be used to treat a disease or addiction, like nicotine addiction, it must provide studies to the FDA showing that its product is safe and effective for that use. On the basis of those studies, the FDA approves or doesn’t approve the product. So far, there are no large, high-quality studies looking at whether e-cigarettes can be used to cut down or quit smoking long-term. Most of the studies have been either very short term (6 months or less) or the participants were not randomly assigned to different methods to quit smoking, including e-cigarettes. Many of the studies are based on self-reported use of e-cigarettes. For example, a study done in four countries found that e-cigarette users were no more likely to quit than regular smokers even though 85% of them said they were using them to quit.[6] Another year-long study, this one in the U.S., had similar findings.[7] People may believe they are smoking e-cigarettes to help them quit, but 6-12 months after being first interviewed, nearly all of them are still smoking regular cigarettes.

Until there are results from well-conducted studies, the FDA has not approved e-cigarettes for use in quitting smoking.[8]

Teenagers, Children, and E-Cigarettes

The percentage of teenagers who have tried e-cigarettes has almost quadrupled in just four years, from 5% in 2011 to 19% in 2015. Three million U.S. students in middle school and high school tried e-cigarettes in 2015, according to the National Youth Tobacco Survey. And, 1 in 5 middle schoolers who said they had tried e-cigarettes also said they had never smoked conventional cigarettes.[9]

E-cigarette use by young people is worrisome for a number of reasons:

1) The younger people are when they begin smoking, the more likely it is they will develop the habit: nearly 9 out of 10 smokers started before they were 18.[10]

2) Nicotine and other chemicals found in e-cigarettes might harm brain development in younger people.[11]

3) E-cigarettes may introduce many more young people to smoking who might otherwise never have tried it, and once they are addicted to nicotine, some may decide to get their “fix” from regular cigarettes. Whether e-cigarettes end up being a “gateway” to regular cigarettes or not, young people who use them risk becoming addicted to nicotine and exposing their lungs to harmful chemicals.

The sharp rise in young e-cigarette users highlights the need to stop manufacturers from targeting teenagers with candy-like flavors and advertising campaigns.

Even children who are too young to smoke have been harmed by e-cigarettes. The liquid used in e-cigarettes is highly concentrated, so absorbing it through the skin or swallowing it is far more likely to require an emergency room visit than eating or swallowing regular cigarettes. In 2012, less than 50 kids under the age of six were reported to poison control hotlines per month because of e-cigarettes. In 2015, that number had skyrocketed to about 200 children a month, almost half of which were under the age of two![12]

How Are E-Cigarettes Regulated?

The FDA was given the power to regulate the manufacturing, labeling, distribution and marketing of all tobacco products in 2009 when President Obama signed into law the Family Smoking Prevention and Tobacco Control Act and in 2010 a court ruled that the FDA could regulate e-cigarettes as tobacco products.[13]

It wasn’t until 2016 that the FDA finally announced a rule to regulate e-cigarettes.[14] Under the final rule, the FDA plans to ban the sale of e-cigarettes to anyone under the age of 18. The rule also requires all makers of e-cigarettes sold after February 15, 2007 to go through a “premarket review.” This is the process that the FDA uses to determine whether potentially risky products are safe. However, companies are allowed to have anywhere from 18 months to two years to prepare their applications. And it will take another year for the FDA to actually approve these applications. So don’t expect e-cigarettes currently on the market to be officially allowed to be sold by the FDA for another couple of years.

In the meantime, individual states have always had the power to pass laws restricting the sale and use of e-cigarettes. For example, in May 2013, the California state senate proposed a law making all e-cigarettes subject to the same regulations and restrictions as traditional cigarettes and tobacco products. However, that did not become law.

The Bottom Line

E-cigarettes have not been around long enough to determine if they are harmful to users in the long run. Unfortunately, many people, including teenagers, are under the impression that e-cigarettes are safe or that they are effective in helping people quit smoking regular cigarettes. Neither of these assumptions has yet been proven. Studies by the FDA show that e-cigarettes contain some of the same toxic chemicals as regular cigarettes, even though they don’t have tobacco. The big three tobacco companies—Lorillard, Reynolds American, and Altria Group—all have their own e-cigarette brands, so it’s not surprising that e-cigarettes are being marketed and advertised much the way regular cigarettes used to be. Here are the 7 Ways E-Cigarette Companies Are Copying Big Tobacco’s Playbook.

Unless you want to be a guinea pig, hold off on e-cigarettes until more safety information is available. And if you need help quitting or reducing the number of cigarettes you are smoking, check out the smokefree.gov website.

Prostate Cancer: Diet and Dietary Supplements

February 29, 2016Diet, Habits, & Other Behaviors, Prevention, Prostate CancerCPTFeditor

Brandel France de Bravo, MPH, Caitlin Kennedy, PhD, Anna E. Mazzucco, PhD, and Laura Gottschalk, PhD, Cancer Prevention & Treatment Fund

Prostate cancer is the second most common cancer among American men, and the second leading cause of cancer deaths among them as well. The American Cancer Society estimates almost 192,000 new diagnoses of prostate cancer in 2020, and more than 33,000 prostate cancer related deaths.[1]

Compared to most cancers, prostate cancer usually progresses very slowly, and many men live with it for years and even decades. Once diagnosed, some men decide to undergo treatment to halt the progression of the disease, and others refrain from treatment, preferring instead to closely monitor the cancer’s progression. Those who choose “active surveillance” do this because the medical and surgical treatments for prostate cancer often cause very undesirable side effects, and because most men with prostate cancer will die from something else. This strategy is especially likely for older men in the earliest stage of the disease.

At one time, it was unheard of to suggest that diet might have a role to play in battling prostate cancer. But there is now evidence that certain foods and dietary supplements have an impact on prostate health—both positive and negative. Some foods or supplements appear to promote prostate health and prevent cancer cells from developing, but others should not necessarily be taken by men who already have prostate cancer.

The role of diet drew researchers’ attention when they noticed that prostate cancer rates vary greatly from one country to another, with the highest rates appearing in countries where people tend to eat a lot of fat. Studies also show that men who are obese or have a high fat diet are more likely to have prostate cancer.[2] Diets high in saturated fats, such as the animal fats found in red meat, may pose the greatest risk. The lowest rates of prostate cancer are found in Asian countries where men eat a lot of soy foods, a rich source of naturally occurring phytoestrogens. It was hoped that by increasing men’s intake of phytoestrogens, they might reduce their risk of prostate cancer, slow its progression, or reduce the risk of prostate cancer recurring, but at least three studies have failed to find any protective benefit from phytoestrogens.[4][5][6]

Dietary Supplements

As more and more people take dietary supplements containing antioxidants, studies have been conducted to determine their effect on reducing the risk and growth of cancers, including prostate cancer. Three antioxidants that have received attention with regard to prostate health are vitamin E, selenium, and vitamin D.

Studies comparing men who live in areas of the country with high levels of selenium to men in areas with low levels suggest that this mineral protects against prostate cancer. Selenium was believed to reduce the risk of developing prostate cancer because it keeps cells from proliferating or dying off in a rapid or unusual way. An analysis in 2002 of the Nutritional Prevention of Cancer Trial revealed that the men who took selenium supplements daily were half as likely to be diagnosed with prostate cancer.[7] However, a 2014 report based on the Selenium and Vitamin E Cancer Prevention Trial (SELECT) indicated that selenium supplements increased the risk of prostate cancer by 91% and taking vitamin E supplements increased the risk of prostate cancer by 17%.[8] This result led the researchers to discourage men over 55 from taking amounts of vitamin E higher than the recommended dietary allowance (RDA), which is 15 mg of alpha-tocopherol. Moreover, a 2009 study found that higher selenium levels in the blood may worsen prostate cancer in many men who already have the disease.[9] As a result of this trial, the researchers have encouraged men over 55 to limit their intake of selenium to the recommended dietary allowance (RDA) of 55 mcgs.

The SELECT findings on selenium don’t mean that antioxidants have no role to play in preventing cancer or slowing its spread. Some antioxidants may be helpful but some may encourage small cancers to grow larger. A 2014 study by researchers in the U.K. tested the effect of Pomi-T, a supplement that contains broccoli, pomegranate, green tea, and turmeric on the health of men with prostate cancer. After six months, they found that the men taking Pomi-T had a smaller increase in PSA, a protein that becomes elevated with prostate cancer, as compared to men with prostate cancer who didn’t take Pomi-T. The researchers suggest that the unique blend of polyphenols and antioxidants in the supplement had a beneficial effect on health of these prostate cancer patients.[10]

A study published in 2016 brought yet another antioxidant, vitamin D, into the prostate cancer discussion. Vitamin D is well known for its role in helping build strong bones and teeth, but it may also contribute to the fight against cancer (read more here AND here). The prostate cancer study looked at the levels of vitamin D in men who had their prostates removed due to cancer. They found that men who had the most aggressive forms of prostate cancer had lower levels of vitamin D in their blood compared to men with less aggressive forms of cancer.[11] It is not yet known whether higher levels of vitamin D prevent more aggressive forms of prostate cancer or if aggressive prostate cancer lowers levels of vitamin D. Since it is impossible to know if low levels of vitamin D is a cause or effect of aggressive prostate cancer, and since high levels of vitamin D can be dangerous, more research is needed before experts will know if men diagnosed with prostate cancer should try to take more vitamin D.

Bottom Line: We need studies to determine exactly how diet and dietary supplements can be used to prevent prostate cancer and slow its spread. Meanwhile, men should reduce saturated fats as much as possible. While the jury is still out on phytoestrogens, men may benefit from eating more soy products—especially if they are eating them in place of red meat!

For more on cancer and antioxidants, read here.

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

American Cancer Society. Key Statistics for Prostate Cancer. Cancer.org. https://www.cancer.org/cancer/prostate-cancer/about/key-statistics.html. Updated 2020.
Narita, S., Nara, T., Sato, H., Koizumi, A., Huang, M., Inoue, T., & Habuchi, T. (2019). Research evidence on high-fat diet-induced prostate cancer development and progression. Journal of clinical medicine, 8(5), 597.
Ma R, Chapman K. A systematic review of the effect of diet in prostate cancer prevention and treatment. Journal of Human Nutrition and Dietetics. Vol (22)2009:187-199.
Ganry O. Phytoestrogens and prostate cancer risk. Preventive Medicine. Vol (41) 2005:1-6.
Ward H, Chapelais G, Kuhnle GC, Luben R, Khaw KT, Bingham S. Lack of Prospective Associations between Plasma and Urinary Phytoestrogens and Risk of Prostate or Colorectal Cancer in the European Prospective into Cancer-Norfolk Study. Cancer Epidemiology Biomarkers & Prevention Vol (17) 2008: 2891-2894.5
Bosland MC, Kato I, Zeleniuch-Jacquotte A, Schmoll J, Rueter EE, Melamed J, Kong MX, Macias V, Kajdacsy-Balla A, Lumey LH, Xie H, Gao W, Walden P, Lepor H, Taneja SS, Randolph C, Schlicht MJ, Meserve-Watanabe H, Deaton RJ, & Davies JA. Effect of soy protein isolate supplementation on biochemical recurrence of prostate cancer after radical prostatectomy. JAMA 2013; 310(2): 170-178. doi: 10.1001/jama.2013.7842
Duffield-Lillico AJ, et al. Baseline characteristics and the effect of selenium supplementation on cancer incidence in a randomized clinical trial: A summary report of the Nutritional Prevention of Cancer Trial.Cancer Epidemiology, Biomarkers, and Prevention. Vol (11) 2002: 630-639.
Kristal AR, et al., Baseline Selenium Status and Effects of Selenium and Vitamin E Supplementation on Prostate Cancer Risk. Journal of the National Cancer Institute, 2014.
Chan JM et al. Plasma Selenium, Manganese Superoxide Dismutase, and Intermediate-or High-Risk Prostate Cancer. Journal of Clinical Oncology. Vol (27) 2009: 3577-3583.
Thomas, R., Williams, M., Sharma, H., Chaudry, A., & Bellamy, P. (2014). A double-blind, placebo-controlled randomised trial evaluating the effect of a polyphenol-rich whole food supplement on PSA progression in men with prostate cancer—the UK NCRN Pomi-T study. Prostate Cancer and Prostatic Diseases, 17(2), 180-186.
Nyame Ya, et al. Associations between serum vitamin D and adverse pathology in men undergoing radical prostatectomy. J Clin Oncol. 2016 Feb 22.

Can a handful of nuts a day keep cancer away?

December 10, 2015Breast Cancer, Colon Cancer, Diet, Habits, & Other Behaviors, Ovarian Cancer, Pancreatic Cancer, Preventionbreast cancer, diet, nuts, peanut butterCPTFeditor

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.

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
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
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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. https://breast-cancer-research.biomedcentral.com/articles/10.1186/s13058-015-0571-6
Freitas R.D.S., Campos M.M.. Protective effects of omega-3 fatty acids in cancer-related complications. (2019). Nutrients;11(5):945. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6566772/#:~:text=Omega%2D3%20polyunsaturated%20fatty%20acids,structure%20and%20fluidity%20of%20membranes
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.

Tanning beds: safe alternative to sun?

September 29, 2015Diet, Habits, & Other Behaviors, Environmental Exposures, Prevention, Skin CancerCPTFeditor

By Heidi Mallis, B.A and Diana Zuckerman, PhD

Updated 2015

For many years, tanning beds were advertised as a safe alternative to a natural suntan, but in fact, there was no evidence that was true. No U.S. government agency evaluated sun lamps, tanning beds, or tanning booths to make sure they were safe. As a result, nearly 30 million people in the U.S. were using tanning beds each year¹, 2.3 million of whom were adolescents.²

Research evidence was growing about the risks of tanning beds. According to the American Academy of Dermatology and the World Health Organization, indoor tanning increases a person’s chances of developing melanoma by 59 percent, and the risk goes up with each use.³

Finally, in 2014 the U.S. Food and Drug Administration (FDA) announced that all sun lamps and UV lamps intended for use in sun lamp products must come with warnings include the following:

This product is contraindicated for persons under the age of 18 years;
This product must not be used if skin lesions or open wounds are present;
This product should not be used on people who have had skin cancer or a family history of skin cancer
People repeatedly exposed to UV radiation should be regularly evaluated for skin cancer³

As evidence grew of the link between tanning beds and skin cancer, especially for men and women in their 20s, more than 60% of states passed some kind of legislation restricting the use of tanning salons by children under 18 and two states, California and Vermont, have passed complete bans of indoor tanning for minors.⁴

What does this mean for you?

Tanning beds expose the user to a lot of artificial UV radiation in a short period of time. Just one 8-20 minute session exposes a person to more UV radiation than an entire afternoon spent in natural sunlight. In fact, doses of UV radiation emitted by high pressure sunlamp products may be up to 10 to 15 times higher than that of the midday sun, which is more intense than UV radiation found in nature.

A study conducted by Dr. S. Elizabeth Whitmore and Dr. Warwick Morison of Johns Hopkins University School of Medicine found that ten tanning sessions in two weeks produced evidence of a suppressed immune system among participants. This means that the body is less capable of fighting off infectious agents.⁵ Tanning bed use is also associated with faster skin aging because the UV radiation destroys skin fibers and damages elasticity. Characteristics of skin aging include wrinkles, dark spots, and a leathery texture.⁶

The International Agency for Research on Cancer lists tanning beds in its highest cancer risk category, “carcinogenic to humans.” This means that there is enough evidence to conclude that tanning beds can cause cancer in humans. Prior to 2009, the agency, which is part of the World Health Organization (WHO), previously classified tanning beds as “probably carcinogenic.” The change came after an analysis of more than 20 epidemiological studies indicating that people who begin using tanning devices before age 30 are 75% more likely to develop cutaneous melanoma, the most serious type of skin cancer⁷

Skin cancer is the most common form of cancer, with more than one million cases diagnosed each year in the U.S. There are three types of skin cancer: squamous cell, basal cell, and melanoma. Squamous cell carcinomas typically occur on surfaces exposed to the most sunlight, such as the ears or face. This type of skin cancer can spread quickly to other organs in the body. Basal cell carcinomas account for 8 out of 10 skin cancers. They grow very slowly and rarely spread to other parts of the body (as a result, they are highly treatable). Melanomas are the third and most dangerous type of skin cancer. They are less common than basal and squamous cell carcinomas but much more serious.⁸ Melanomas usually present as a change to an existing mole or an entirely new mole that is black or has a blue-black area. Their diameter is typically larger than that of a pencil eraser. If caught early, melanomas are often completely curable. However, they are much more likely to spread to other parts of the body if not found early.⁹

Risk factors for all three types of skin cancer include:

Lifetime exposure to UV radiation (from natural or artificial sources)
Family history of skin cancer
Geographic location (people who live close to the equator as well as in the mountains are exposed to higher levels of UV radiation)
Fair skin that freckles or burns easily
Severe sunburns as a child
Radiation therapy

Here are a few ways to lower your risk and avoid wrinkles and other skin damage:

Avoid direct sun exposure during midday hours (from 10 am-4 pm),
Use sunscreen with a sun protection factor (SPF) of at least 15
Regularly check your skin for any new moles, sores, or scaly patches (and visit a dermatologist if you notice the lesion changing form or color), and
Avoid using a tanning bed or booth (especially if you are a child, teenager, or young adult).¹⁰

Keeping track of moles and other changes to your skin are an easy way to improve your skin health. However, the U.S. Preventive Services Task Force suggests that if you are not at an increased risk of developing skin cancer, there is no need for yearly skin checks by a dermatologist.¹¹

Continue to monitor any existing or new moles and contact your doctor if you detect any significant changes in size, shape, or color.

The Benefits of Exercise After Getting Diagnosed with Cancer

July 16, 2015Breast Cancer, Colon Cancer, Diet, Habits, & Other Behaviors, General Treatment Issues, Prevention, Quality Of LIfe, Treatment & ManagementexerciseCPTFeditor

Morgan Wharton and Annika Schmid, Cancer Prevention and Treatment Fund

You may have heard that regular exercise can reduce your risk of developing cancer, but did you know it’s also good for cancer patients who are undergoing or have completed treatment?

Is Exercise Good for Everyone Diagnosed with Cancer?

Exercise has proven benefits for cancer patients, ranging from improved fitness and higher quality of life to reduced rates of recurrence and a longer life.[1-9] What we know about exercise and cancer mostly comes from studying patients with breast or colon cancer, but there’s reason to believe that there are benefits of exercise for men and women suffering from all types of cancer, even cancer as advanced as Stage III.[3, 7]

The best news of all: It doesn’t matter if you were fit before you got diagnosed. Whether or not you exercised before has no bearing on what exercise can do for you during and after treatment.[3, 4, 6] So, it’s never too late to use exercise to fight cancer. If you’re coping with cancer or its aftermath, now is the time.

What Does the Science Show about Exercise for Cancer Patients?

Many studies have shown that exercise is beneficial to cancer patients, but no one is sure exactly why. Earlier studies suggested that exercise may help women avoid breast cancer or a recurrence of it by decreasing female hormones that feed cancer in the breast,[10-11] or by lowering inflammation in the body,[12] a suspected contributor to many diseases. In 2014, a study was published that provides a new possible explanation for how exercise helps the body fight cancer.[13] Researchers looked at irisin, a protein released from muscles after exercise, to see how it would affect breast cancer cells and healthy breast cells in test tubes. What they found was that when breast cancer cells came into contact with irisin, they started to self-destruct in a programmed way. While the exercise protein reduced the number of malignant cells and their ability to move around, it left the healthy cells unharmed! The researchers also found that irisin made Doxorubicin, a chemotherapy drug commonly given to breast cancer patients, more effective at killing cancer cells. Though this study did not look at what happens to cancer cells in actual patients after they exercise, it could help explain why other studies have found that cancer patients who are physically active feel better during treatment and are less likely to have their cancer come back.

A study from 2020 found that exercise is beneficial for preventing cancer deaths. It examined how active people were per day, and found that people who were more active were less likely to die from cancer by a follow-up 6 years later.[14] However, the study did not include people who were undergoing cancer treatment when the study was measuring physical activity, which makes sense since cancer treatment can drastically reduce the ability to exercise. This means that the results of the study are not specifically about people undergoing cancer treatment.

Studies that did look at patients focused on those beginning exercise (such as walking or aerobic exercise with weight training) somewhere between 2 weeks and 1 year after completing cancer treatment. In these studies, treatment could include surgery, chemotherapy, radiation, or a combination of these therapies.[1, 2, 3, 4, 6, 7, 8] Some studies also examined the effects of exercise during cancer treatment.[5, 9]

Less Body Fat and Better Immune System:

Studies have shown that in cancer patients, exercise during or after treatment reduces fat and improves body mass index (BMI).[2, 6, 9] Exercise lowers blood pressure, boosts the immune system, and increases bone mineral density.[6, 8, 9] Denser bones means fewer fractures.

Improved Fitness:

As expected, cancer patients who exercise regularly during and after treatment reported increases in strength, walking ability, aerobic capacity, and flexibility.[2, 6, 9]

Less Fatigue and Fewer Side Effects from Treatment:

Cancer patients who had completed treatment reported fewer negative side effects from treatment once they began to exercise regularly.[7] Patients who exercised during treatment reported less nausea and less difficulty sleeping.[9] The most commonly reported improvement was reduced fatigue. [6, 8, 9] In addition, a study published in 2021 indicates that exercise may also help relieve “chemo brain” (also known as chemo fog), which is a common side effect for cancer patients undergoing chemotherapy.[15] Common symptoms of chemo brain are having trouble with learning new tasks, remembering names, paying attention, and concentrating. The study found that patients who did either 2.5-5 hours of moderate intensity exercise (like brisk walking) per week or who did 1.5-2.5 hours of high intensity exercise (such as running) per week in the week before starting chemotherapy, within 1 month of completing chemotherapy, and 6 months after completing chemotherapy were less likely to report “chemo brain” symptoms than patients who did not exercise. Chemo brain can be upsetting and debilitating, affecting more than 75% of breast cancer patients undergoing chemotherapy, for example.

Better Quality of Life:

In addition to the physical health benefits of exercise, cancer patients who exercised also reported improved mental and emotional well-being.[2] Patients who exercised during treatment and those who began to exercise afterwards frequently reported an increase in quality of life.[9] Patients who began to exercise regularly after treatment experienced less anxiety and a renewed “fighting spirit.”[9] Cancer patients over the age of 80 who exercised regularly during their weeks or months of treatment reported less loss of memory.[5]

Reducing Cancer Recurrence and Other Benefits for Survivors:

Because exercise improves the immune system, cancer patients who exercise regularly lower their risk of the cancer returning.[1, 2, 3, 8] Patients who exercise are less likely to die from cancer and are more likely to live longer than patients who don’t exercise.[14]

A 2022 study found that cancer survivors who exercise and do not sit 8 or more hours a day live longer than less active cancer survivors.[16] The study followed over 1,500 cancer survivors ages 40 and over for an average of 4.5 years. The researchers found that those who exercised at least 150 minutes per week were less likely to die (of cancer or anything else) than people who did not report exercising. Survivors who reported sitting for more than 8 hours a day were also more likely to die than those who reported sitting less than 4 hours per day, and survivors who reported both a lack of exercise and sitting more than 8 hours per day were the most likely to die of all the survivors studied. The researchers recommend that cancer survivors stay active, by exercising 150-300 minutes per week and by standing and moving as much as possible, rather than sitting.

What Kind of Exercise Should I Do?

Aerobic activity of light to moderate intensity was the most common type of exercise in the studies of cancer patients.[2, 3, 6, 8, 9] Combining aerobic exercise with walking and resistance training (such as weight lifting or using resistance bands) led to greater health benefits than aerobic activity alone.[2, 6, 8]

Most studies used Metabolic Equivalent (MET) hours to measure physical activity by level of intensity. MET hours measure the energy output of various activities compared to the energy used by the body when at rest. Activities that require more effort have a higher MET score than activities with lower intensities. One study suggested that 18-27 MET hours per week represents the ideal rate of exercise, because that group showed the lowest rate of recurrence and more activity did not lead to increased benefits.[7] Having a MET score comparable to 6 or more hours of walking in a week showed a 47% higher chance of survival without recurrence.[3] Click here for a chart of various activities and their MET hour equivalent, so you can calculate your weekly exercise in MET hours and maximize your benefits from exercise.

Walking can improve the health of cancer patients. Studies estimate that the greatest benefit from walking is seen in patients who walk at an average speed(a 20 minute mile) for 3-5 hours weekly.[7] Patients who walked just 1 hour per week, regardless of walking speed, showed improvements over the group of patients who reported no physical activity in a week.[7]

To get the most out of exercise, you need to make it a habit—something you commit to for the long-term. That’s why it is better to start small, with easily achievable changes like using the stairs regularly instead of the elevator or walking each evening after dinner. Remember not to set unrealistic goals, because it is better to start small and keep it up than to try to do too much and give up. Don’t miss the chance to get at least some benefit from this easy, free strategy to fight cancer.

The Bottom Line

Exercise helps individuals who are undergoing cancer treatment and those who have completed cancer treatment. Cancer patients who exercise regularly during and after treatment can expect fewer side-effects from treatment, including less fatigue, fewer problems with concentration and memory, and better overall fitness and health. Patients who exercise are less likely to experience a return of cancer in the future and are more likely to live longer, healthier lives.

You should try to walk at least six hours a week at an average pace (about 1 mile per 20 minutes).

Even minimum exercise, like walking one hour per week, can improve the health of cancer patients who have completed treatment, compared to cancer patients who do not exercise at all. The benefits from exercise can be seen in all cancer patients, regardless of whether or not they exercised regularly before they were diagnosed with cancer. It’s never too late to begin to exercise and improve your health!

References

Barbara Sternfeld, E.W., Charles P. Quesenberry, Jr., Adrienne L. Castillo, Marilyn Kwan, Martha L. Slattery, and Bette J. Caan, Physical activity and risk of recurrence and mortality in breast cancer survivors: Findings from the LACE study. Cancer Epidemiology, Biomarkers & Prevention, 2009. 18(1): p. 87-95.
Daniel Y T Fong, J.W.C.H., Bryant P H Hui, Antoinette M Lee, Duncan J Macfarlane, Sharron S K Leung, Ester Cerin, Wynnie Y Y Chan, Ivy P F Leung, Sharon H S Lam, Aliki J Taylor, Kar-keung Cheng, Physical activity for cancer survivors: Meta analysis of randomised controlled trials. British Medical Journal, 2012. 344(70).
Jeffrey A. Meyerhardt, D.H., Donna Niedzwiecki, Donna Hollis, Leonard B. Satz, Robert J. Mayer, James Thomas, Heidi Nelson, Renaud Whittom, Alexander Hantel, Richard L. Schilsky, and Charles S. Fuchs, Impact of physical activity on cancer recurrence and survival in patients with stage III colon cancer: Findings from CALGB 89803. Journal of Clinical Oncology, 2006. 24(22): p. 3635-3541.
Jeffrey A. Meyerhardt, E.L.G., Michelle D. Holmes, Andrew T. Chan, Jennifer A. Chan, Graham A. Colditz, and Charles S. Fuchs, Physical activity and survival after colorectal cancer diagnosis. Journal of Clinical Oncology, 2006. 24(22): p. 3527-3534.
LK Sprod, S.M., W Demark-Wahnefried, MC Janelsins, LJ Peppone, GR Morrow, R Lord, H Gross, KM Mustian, Exercise and cancer treatment symptoms in 408 newly diagnosed older cancer patients. Journal of Geriatric Oncology, 2012. 3(2): p. 90-97.
Margaret L. McNeely, K.L.C., Brian H. Rowe, Terry P. Klassen, John R. Mackey, Kerry S. Courneya, Effects of exercise on breast cancer patients and survivors: A systematic review and meta analysis. Canadian Medical Association Journal, 2006. 175(1): p. 34-41.
Michelle D. Holmes, W.Y.C., Diane Fesknich, Candyce H. Kroenke, Graham A. Colditz, Physical activity and survival after breast cancer diagnosis. Journal of the American Medical Association, 2005. 293(20): p. 2479-2486.
Rosalind R. Spence, K.C.H., Wendy J. Brown, Exercise and cancer rehabilitation: A systematic review. Cancer Treatment Reviews, 2009. 36: p. 185-194.
Ruud Knols, N.K.A., Daniel Uebelhart, Jaap Fransen, and Geert Aufdemkampe, Physical exercise in cancer patients during and after medical treatment: A systematic review of randomized and controlled clinical trials. Journal of Clinical Oncology, 2005. 23(16): p. 3830-3842.
Key T, Appleby P, Barnes I, Reeves G. Endogenous sex hormones and breast cancer in postmenopausal women: reanalysis of nine prospective studies. J Natl Cancer Inst. Apr 17 2002;94(8):606-616.
McTiernan A, Tworoger SS, Ulrich CM, et al. Effect of exercise on serum estrogens in postmenopausal women: a 12-month randomized clinical trial. Cancer Res. Apr 15 2004;64(8):2923-2928.
Friedenreich CM, Neilson HK, Woolcott CG, et al. Inflammatory Marker Changes in a Yearlong Randomized Exercise Intervention Trial among Postmenopausal Women. Cancer Prevention Research. January 1, 2012 2012;5(1):98-108.
Gannon NP, Vaughan RA, Garcia-Smith R, Bisoffi M, Trujillo KA. Effects of the exercise-inducible myokine irisin on malignant and non-malignant breast epithelial cell behavior in vitro. Int J Cancer. Feb 15 2015;136(4):E197-202.
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.
Elizabeth A. Salerno, Eva Culakova, Amber S. Kleckner, Charles E. Heckler, Po-Ju Lin, Charles E Matthews, Alison Conlin, Lora Weiselberg, Jerry Mitchell, Karen M. Mustian, Michelle C. Janelsins. Physical Activity Patterns and Relationships With Cognitive Function in Patients With Breast Cancer Before, During, and After Chemotherapy in a Prospective, Nationwide Study. Journal of Clinical Oncology. 2021. https://ascopubs.org/doi/full/10.1200/JCO.20.03514.
Cao, C, Friedenreich, CM and Yang L. Association of Daily Sitting Time and Leisure-Time Physical Activity With Survival Among US Cancer Survivors
JAMA Oncology, January 6, 2022 online, https://jamanetwork.com/journals/jamaoncology/article-abstract/2787951

Antioxidants and cancer risk: the good, the bad, and the unknown

July 11, 2015Diet, Habits, & Other BehaviorsCPTFeditor

By Nyedra W. Booker, PharmD, MPH and Diana Zuckerman, PhD

Updated 2015

Do you take vitamin pills or dietary supplements? If so, you are not alone! Most adults in the U.S. take at least one dietary supplement,¹² and products with claims of cancer and other disease-fighting benefits are increasingly popular. Vitamins A, C, E, beta carotene and selenium are all considered “antioxidants,” and people take them hoping to prevent disease and improve overall health. You have probably heard that antioxidants fight cancer, but the latest research suggests that any benefits they have in preventing cancer may be reversed for people who already have cancer (including those who have cancer but haven’t been diagnosed yet).

What are antioxidants?

Antioxidants prevent a chemical process known as “oxidation,” which is a natural part of living and aging. Oxidation damages cells and can lead to the development of disease, including Alzheimer’s, heart disease, and cancer. Antioxidants are found in fruits, vegetables, nuts, beans, grain cereals, and other foods. Even dark chocolate is rich in antioxidants.

The antioxidants made by our body play an important role in finding and repairing damaged cells, as well as boosting our immune system. But do antioxidants in dietary supplements provide the same health benefits as the antioxidants we make on our own? Supplements are often produced using man-made products or by extracting the antioxidants from certain foods. Unfortunately much of the health benefits may be lost during these manufacturing processes.¹³

The good, the bad and the unknown

A landmark study from the late 1980s was among the first to look at the effect of antioxidants on cancer risk. The study involved almost 30,000 Chinese men and women at high risk for cancer who took daily vitamin and mineral supplements for 5 years. Patients were assigned to receive one of the following combinations of supplements: (a) retinol and zinc, (b) riboflavin and niacin, (c) vitamin C and molybdenum, or (d) beta carotene, vitamin E and selenium. Men and women taking the antioxidant combination of beta carotene, vitamin E and selenium had significantly lower death rates and a reduced risk for cancer after 1-2 years of taking the supplements.¹⁴

However, excitement about antioxidants to prevent cancer was short-lived. In 1994, the New England Journal of Medicine (NEJM) published findings from an 8-year study on antioxidant use to prevent lung cancer in men who smoke. Almost 30,000 male smokers age 50-69 were randomly assigned to one of the following: (a) vitamin E, (b) vitamin E + beta carotene, (c) beta carotene or (d) placebo (a sugar pill). But rather than reduce the risk for lung cancer, the men taking beta carotene (either alone or in combination with vitamin E) were more likely to develop lung cancer after only 18 months of daily beta carotene use, and the number of lung cancer cases continued to increase disproportionately for the duration of the study.¹⁵

In 1996, a study of more than 18,000 men and women at high-risk for lung cancer looked at whether antioxidants could reduce the risk of lung cancer in high-risk patients. Study participants included current smokers, former smokers, and workers with prior exposure to asbestos, who were randomized to receive beta carotene, vitamin A or placebo. The study was stopped early when preliminary results showed a 17% higher death rate in the antioxidant groups.¹⁶

These two lung cancer studies caused great concern about antioxidants. Beta carotene was discontinued two years into a study involving 540 patients with head and neck cancer taking a combination of vitamin E + beta carotene supplements to prevent a second cancer. But the researchers found a significant increase in the risk of a second cancer in the patients who continued to take vitamin E. Once this supplement was discontinued, the cancer risk decreased to that of patients taking the placebo.¹⁷

A 2012 review of almost 80 randomized clinical studies of antioxidant use (vitamin A, C, E, beta-carotene and selenium) again showed cause for concerns. Together the studies included a total of almost 300,000 men and women (described as both “healthy” and with diseases in a “stable phase”). Men and women were more likely to die if they were taking Vitamin E, beta-carotene or doses of vitamin A that exceed the Recommended Dietary Allowance (700µg for women and 900µg for men). The authors concluded that the use of antioxidant supplements could be dangerous for the general population and those diagnosed with various diseases.¹⁸

What could explain the possible increased cancer risk?

Starting around 2008, there was growing evidence that antioxidants could be dangerous for anyone who already had cancer, and that could explain some of the contradictory results of previous studies. In one study, large doses of vitamin C supplements reduced the effectiveness of several anti-cancer drugs including Methotrexate, Doxorubicin and Imatinib, resulting in 30-70% fewer cancer cells killed. The authors concluded that vitamin C may actually be helping cancer cells survive by protecting the cells’ power source.¹⁹ In another study, the antioxidants vitamin C and N-acetyl cysteine (often sold under the name “NAC”) significantly reduced the effectiveness of anti-cancer drugs Vinblastine and Cisplatin.²⁰

As more recent studies continue to suggest antioxidants could actually help cancer cells grow, research by Zachary Schafer shows that cancer cells’ survival can be aided by antioxidants that protect these cells from free radicals.²¹ Free radicals harm cells, and getting rid of free radicals therefore can help cancer cells. “If you are a person who is healthy, meaning no tumors of any kind, antioxidants are probably going to protect against cancer,” Schafer says. But he points out that if a person has cancer cells, antioxidants can help those cancer cells survive.

The bottom line

Dietary supplements are intended to be used when your body is not receiving certain nutrients in the right amounts, but like drugs, they can have unintended side effects so they should only be taken as recommended.

If a person definitely doesn’t have cancer, antioxidants can help them. However, if they have cancer, even if they have early cancer that hasn’t been diagnosed yet (which is certainly a risk for heavy smokers or former smokers, for example), antioxidants could be harmful.

It may be tempting to go out and buy nutritional products that claim to be all-natural and will make you feel great and stay healthy. Remember, however, that a product labeled as being “natural” or “organic” is not necessarily safe. The Food and Drug Administration (FDA) does not test the safety and effectiveness of nutritional supplements before they are placed on the shelf the way they do for prescription and over-the-counter medications. Consequently, you may be purchasing a product that is neither safe nor effective!

So what are some proven strategies that can help reduce your risk of cancer?

Maintain a healthy weight by limiting the high-calorie foods you eat and getting regular physical activity
Eat plenty of fruits and vegetables every day (fruits and vegetables should cover half of your plate. For more tips, see My Plate: A New Alternative to the Food Pyramid)
Limit the amount of red meat and processed meat (hot dogs, sausages, bologna, etc.) that you eat
Eat foods made of whole grains

Weight and cancer: What you need to know

June 15, 2015Diet, Habits, & Other BehaviorsobesityCPTFeditor

Brandel France de Bravo, MPH, Noy Birger, Shahmir Ali ABD, and Ealena Callender, MD, MPH, Cancer Prevention and Treatment Fund

There are many reasons why being overweight is bad for our health, but most people
don’t realize that cancer is one of them. Of course, excess body weight can contribute
to serious medical conditions such as heart disease and type II diabetes. Still, more
recent research shows that excess body fat also increases the risk of developing certain
types of cancer.

Researchers estimate that more than 481,000 of newly-diagnosed cancer cases
worldwide in 2012 were due to overweight or obesity. [1]An estimated 111,000 cancer
cases in North America are caused by being overweight or obese. This represents 23%
of total global cancer cases – the highest of any region. In addition, three cancers
accounted for 73% of all obesity-related cancers among women globally: endometrial
cancer, postmenopausal breast cancer, and colon cancer. For men, kidney and colon
cancers accounted for 66% of all obesity-related cancers. Other cancers associated
with overweight and obesity include prostate cancer, several gastrointestinal cancers,
and non-Hodgkin’s lymphoma.

In 2018, American Cancer Society researchers concluded that each year from 2011 to
2015, approximately 37,700 cancer cases in men in the U.S. and 74,700 cancer cases
in women aged 30 years or older were attributable to excess body weight. [2] Among men,
the excess cancers ranged from 3.9% in Montana to 6.0% in Texas. In women, the
excess risk of cancer was almost twice as high as for men, ranging from 7.1% in Hawaii
to 11.4% in Washington, DC. The highest number of weight-related cancers were
primarily found in southern and midwestern states, as well as Alaska and Washington,
D.C. Overall, cancers attributable to excess body weight account for at least 1 in 17 of
all cancers in each state.

The good news is that a large 2014 study showed that with a healthy diet and regular
exercise, postmenopausal women may significantly reduce their cancer risk. [3] In the
study, researchers defined a healthy diet as one that limits red meat and processed
meat, emphasizes whole grains over refined grains, and includes two and a half cups of
vegetables and fruits daily. In addition, regular exercise involves at least 150 minutes of
moderate-intensity physical activity or 75 minutes of vigorous-intensity physical activity
every week. Those with the healthiest diets and most active lifestyles saw their chance
of getting breast cancer drop by 22%, their likelihood of colon cancer drop by 52%, and
their overall chance of dying during the 12-year study drop by 27%. While all the women
who ate better and exercised more lowered their chances of developing cancer, non-
white women seemed to benefit the most.

A 2020 study of more than 8,000 Black and White men and women also found that
exercise helps lower the likelihood of dying from cancer. The study found that inactive
people (whether couch potatoes or sitting at a desk all day) were more likely to die from
cancer. At the same time, those who engaged in light to moderate physical activity were
less likely to die from cancer. [4]

In 2022, a study of adults aged 59 to 82 found that those who were as physically active
as was recommended by the Physical Activity Guidelines for Americans were less likely
to die of cancer than those who were less active. [5] All men and women in the study
who were at least moderately active were less likely to die from cancer or
cardiovascular disease than those who were not active at all. In addition, when
researchers evaluated the type and intensity of activity, the activity that seemed most
likely to reduce the chance of dying from cancer was running, followed by other aerobic
exercise, swimming, and cycling.

How does obesity increase the risk of developing cancer?

Excess body weight results in extra body fat – which has unique features that can make
it more likely for an obese person to get cancer. [6] Body fat, also known as adipose
tissue, contains an abundance of cells that cause chronic inflammation and make it
easier for tumors to grow.

Chronic inflammation in individuals with excess body fat may also contribute to insulin
resistance. [7] Insulin is a hormone that helps our cells use glucose – a type of sugar
found in the foods we eat – to make energy. Insulin resistance means our bodies can’t
respond properly to insulin, and the glucose we need for energy stays in our blood,
where it can’t be used. Too much glucose in our blood – also referred to as high blood
sugar levels or hyperglycemia – increases the likelihood of getting and dying from
cancer. [8] Elevated blood sugar levels lead to an increase in insulin and similar hormones
that cause tumors to grow. The higher the insulin level of a breast cancer patient, the
greater the chance of death. [9] For example, one study of non-diabetic women with early-
stage breast cancer found that women with the highest fasting insulin levels had three
times the risk of recurrence and death compared with women with the lowest insulin
levels. High insulin levels may also interfere with the way certain cancer drugs work,
making treatments less effective. [10]

Researchers think the danger of excess weight is partly due to hormones secreted by
fat tissues, such as estrogen. In women, estrogen comes from a different source before
and after menopause. Before menopause, a woman’s ovaries secrete estrogen. After
menopause, estrogen comes from other tissues in the body. For obese postmenopausal
women, most estrogen comes from body fat, which can encourage the growth of cancer
cells. [11,12] Increased estrogen and increased body fat increase the likelihood of
developing postmenopausal breast cancer and endometrial cancer (also called cancer
of the uterus) in women. [11,12]

The location of body fat also may be important. Fat tissue deep inside your body
wrapped around your organs may increase the risk of developing cancer. For example,
one study followed 3,086 men and women for up to seven years and used medical
imaging scans and physical exams to assess the location of excess fat deposits. [13] After
statistically controlling for the effects of age, exercise habits, BMI, and eating habits,
researchers concluded that those with more fat deep inside the body, compared to
those with fat mostly just beneath the skin, were more likely to develop heart disease
and cancer.

How new is this news?

Researchers have documented the link between obesity and cancer
for many years. In 2003, based on a study of more than 900,000 adults, researchers
estimated that 90,000 cancer deaths could be avoided if adults maintained a normal
body weight. [14] Of all deaths from cancer in Americans over age 50, as many as 14% in
men and 20% in women may be attributable to overweight and obesity. [15]

Every additional study helps to explain how it is that fat fuels tumor growth. Renehan et
al.’s 2012 study, which seemed to be groundbreaking at the time, is based in part on an
earlier meta-analysis (a type of statistical analysis that combines many studies) in which
many of the same authors analyzed more than 200 comparable data gathered from
different countries around the world. [16] The meta-analysis found that excess weight in
men was most strongly associated with cancer of the esophagus, thyroid, colon, and
kidneys. According to the meta-analysis, being overweight did not appear to increase a
man’s risk of prostate cancer. On the other hand, one U.S. study found that an
overweight man with prostate cancer is more likely to die of it than a man with prostate
cancer who is not overweight. [17]

According to the meta-analysis, excess weight in women increases the chances of
developing endometrial cancer, cancer of the gallbladder, esophagus, and kidneys. A
few other cancers were also associated with being overweight for both men and
women, including leukemia, multiple myeloma, and non-Hodgkin’s lymphoma, but the
link was weaker. In men, rectal cancer and malignant melanoma also seemed related to
weight. In women, those with a higher BMI were slightly more likely to be diagnosed
with post-menopausal breast cancer, cancers of the pancreas and thyroid, and colon
cancer.

Additional studies have come to similar conclusions. For example, the American
Institute for Cancer Research (AICR) estimated that excess body fat is responsible for
49% of endometrial cancers; 35% of esophageal cancers; 28% of pancreatic cancers;
24% of kidney cancers; 21% of gallbladder cancers; 17% of breast cancers; and 9% of
colon cancers. [18] In addition, AICR estimates that over 100,000 new cases of cancer
each year are due to excess body fat, which is similar to estimates from the 2018
American Cancer Society study.

Neuhouser’s study, conducted at 40 U.S. clinical centers, of women ages 50 to 79
followed for about 13 years, showed that women who gained more than 5% of their
baseline weight during the study’s follow-up period had a modest increase in their
chance of getting breast cancer. [19] The risk was most significant for women with a body
mass index (BMI) over 35 — they were 60% more likely to develop breast cancer than
women of normal weight. Keep in mind that a BMI of 30 or higher is considered obese.

A 2016 study found that the link between obesity and cancer is more robust in some
countries than others. [20] Middle Eastern countries have the highest proportion of
overweight and obesity in the world and a high proportion of obesity-related cancer. [20] In contrast, countries in sub-Saharan Africa and Asia have only seen a limited increase in
BMI over the last 30 years. Likewise, North America and Europe have a large proportion
of obesity-related cancers, while countries in sub-Saharan Africa and Asia have a
smaller proportion of obesity-related cancer.

Several studies show that high dietary fat intake increases the risk of post-menopausal
breast cancer, [21] prostate cancer, [22] and pancreatic cancer. [23] Researchers have also
found that high-fat diets may increase the likelihood of death from cancer, while low-fat
diets reduce the chances of cancer recurrence. [24] It is unclear whether weight or diet is a
stronger predictor of increased cancer risk, although red meat and processed meat
have been found to increase the risk of some cancers. For more information, see our
articles entitled “Red Meat: The News is Not Good” and “Are Processed Meats More
Dangerous Than Other Red Meats?”

Does losing weight reduce your risk of cancer?

Can losing weight help prevent you from getting cancer? The evidence is clear for some
cancers but not for others. For example, postmenopausal women who lose weight may
reduce their chance of getting breast cancer. [25] Also, weight loss may reduce the
likelihood of gastroesophageal reflux – which may be linked to esophageal cancer. In
addition, some studies have found an association between weight loss and decreased
chance of getting prostate cancer.

Men and women who experience significant weight loss after bariatric surgery may
decrease their likelihood of getting cancer. Bariatric surgery, also called weight-loss
surgery, is generally associated with a decrease in body weight of 20% to 35%. [26] A
2022 study of 30,318 men and women compared the incidence of cancer and cancer-
related death between obese patients who had bariatric surgery and those who did not.
The incidence of most types of cancer and cancer-related death was lower in the
surgical weight loss group. This difference was most significant for endometrial cancer –
the cancer most strongly associated with obesity.

Other studies of obese patients who intentionally lost weight found a decrease in certain
factors in the blood that encourage tumor growth. Called tumor growth factors, these
markers represent chronic inflammation and create a setting that makes it easier for cancer cells to grow. [27,28] Estrogen – a hormone associated with postmenopausal breast cancer and endometrial cancer – also decreased in women who intentionally lost weight. [27] The study found that women who experienced just a 10% weight loss saw their blood estrogen levels decrease by at least 33%. Overall, researchers have not reached a conclusion about the association between weight loss and postmenopausal breast cancer. Although one study showed a decreased likelihood when the weight loss occurs after age 30 but before menopause, [28] other studies have found no impact at all. [29]

What we know and don’t know

Decreasing the likelihood of getting cancer is one of the many benefits of achieving and
maintaining a healthy body weight. However, we still do not fully understand how a
person’s weight, diet, level of physical activity, and genes all work together to determine
one’s cancer risk.

Bottom Line

After giving up tobacco, watching your weight and staying active are your best forms of
health insurance. For guidelines and tips on living a healthy lifestyle, read Eating Habits
That Improve Health and Help with Weight Loss and BMI. [30]

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.

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Brandel France de Bravo, MPH and Diana Zuckerman, Ph.D., Cancer Prevention and Treatment Fund

1. Lose weight (Diet and Exercise)

2. Avoid unnecessary hormones

3. Reduce stress

4. Eat the right foods

5. Breastfeeding protects

6. Don’t smoke (or quit, if you do)

7. Do not drink more than 1 alcoholic beverage/day

Caroline Novas, Cancer Prevention and Treatment Fund

How Does MyPlate Work?

History: From MyPyramid to MyPlate

How Do I Plan Family Meals with MyPlate?

Laura Gottschalk, PhD, Cancer Prevention & Treatment Fund

Brandel France De Bravo, MPH, Sarah Miller, Jessica Becker, and Laura Gottschalk, PhD, Cancer Prevention & Treatment Fund

What Are E-Cigarettes?

Are E-Cigarettes Safer Than Traditional Cigarettes?

Can E-Cigarettes Be Used to Cut down or Quit Smoking Regular Cigarettes?

Teenagers, Children, and E-Cigarettes

How Are E-Cigarettes Regulated?

The Bottom Line

Related Content:

Brandel France de Bravo, MPH, Caitlin Kennedy, PhD, Anna E. Mazzucco, PhD, and Laura Gottschalk, PhD, Cancer Prevention & Treatment Fund

Dietary Supplements

By Krista Kleczewski, Claire Karlsson, and Edyth Dwyer

By Heidi Mallis, B.A and Diana Zuckerman, PhD

Updated 2015

Morgan Wharton and Annika Schmid, Cancer Prevention and Treatment Fund

Is Exercise Good for Everyone Diagnosed with Cancer?

What Does the Science Show about Exercise for Cancer Patients?

Less Body Fat and Better Immune System:

Improved Fitness:

Less Fatigue and Fewer Side Effects from Treatment:

Better Quality of Life:

Reducing Cancer Recurrence and Other Benefits for Survivors:

What Kind of Exercise Should I Do?

The Bottom Line

References

By Nyedra W. Booker, PharmD, MPH and Diana Zuckerman, PhD

Updated 2015

What are antioxidants?

The good, the bad and the unknown

What could explain the possible increased cancer risk?

The bottom line

Brandel France de Bravo, MPH, Noy Birger, Shahmir Ali ABD, and Ealena Callender, MD, MPH, Cancer Prevention and Treatment Fund

How does obesity increase the risk of developing cancer?

How new is this news?

Does losing weight reduce your risk of cancer?

What we know and don’t know

Bottom Line