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Yo-Yo Dieting and Cancer

The suspicion that yo-yo dieting – repeated weight loss and regaining, also termed “weight cycling” – could be linked to cancer comes from a number of studies in both animals and humans. The results of those studies suggested that weight cycling might negatively affect key biological processes that protect and repair cells, which could lead to cancer. Now dieters concerned about this potential effect may be able to rest a bit easier. A newly published report has found no association between weight cycling and any type of cancer in men or women. A team of American Cancer Society researchers examined this issue by reviewing data from an investigation that lasted 17 years. They accumulated detailed dietary information on more than 132,000 men and women ages 50 to 74 who were participating in the Cancer Prevention Study II, which was focused on the effect of nutrition on cancer incidence and deaths. The researchers reviewed weight cycling and the incidence of cancer in general and for 15 individual cancers. Over the 17 years of the Cancer Prevention Study more than 25,000 participants did develop cancer, but based on the investigation’s findings lead researcher Victoria Stevens, Ph.D. said that the last thing people struggling to lose weight need worry about is that regaining might lead to cancer. Yo-yo dieting may not be the threat we thought it was.

More Bad News About Red Meat

On the heels of a World Health Organization analysis concluding that processed meat is a carcinogen and red meat a “probable carcinogen” comes a report from Germany linking both of these foods with an increased risk of ischemic stroke – the type caused by blockages in blood vessels supplying the brain. Researchers from the University of Wurzberg analyzed data from about 11,000 mid-life men and women in the U.S. with no other risk factors for stroke such as diabetes or heart disease. After following half of this group for an average of 22.7 years, the investigators concluded that those who consumed the most red meat had a risk of stroke that was 47 percent higher than those who ate the smallest amount of red meat. The investigation showed that eating other sources of protein such as poultry, seafood, legumes and nuts posed no additional risk of stroke. Among the men in the study, those who ate the most red and processed meat had a 62 percent higher risk of stroke than men who ate the least amounts of these foods. The researchers also found that the risk of stroke was 24 percent higher among study participants who reported the highest intake of bacon, sausage and other processed meats compared to those whose intake of these foods was lowest. Because this was an observational study, it doesn’t prove that eating red meat or processed meats caused the strokes that occurred among the participants. Instead, it indicates an association between red and processed meat and ischemic strokes. 

Surprising Health Risks of a TV Habit

Most of us recognize that spending too much time watching television isn’t healthy, but two new investigations have shown that excessive hours in front of the tube can double the risk of premature death or dramatically increase the risk of colon or endometrial cancer. The link to the two types of cancers comes from a German review of 43 studies concluding that being sedentary was associated with a 24 percent increased risk of colon cancer and a 32 percent higher risk of endometrial (uterine) cancer. To make matters worse, the researchers calculated that for each two-hour increase in daily time spent simply sitting, the colon cancer risk rises by eight percent and the endometrial cancer risk by 10 percent. They also found that when the sitting was done in front of the television screen, colon cancer risk increased by 54 percent and the endometrial cancer risk by 66 percent. These risks appeared to be applicable to all of the four million people whose data was included in the 43 studies reviewed, including those who were physically active. More bad news came from researchers in Spain who found that watching three or more hours of television daily can double the risk of premature death among relatively young people. The study focused on over 13,000 college graduates.

My take? A number of studies in recent years have found that too much sitting isn’t good for us. Research has shown that sitting at work (where it may be unavoidable), while driving, and at home are lifestyle habits linked to type 2 diabetes, as well as metabolic syndrome, which increase the risk of diabetes. In addition, heart disease, stroke, and the appearance of fat deposits linked to heart disease have been tied to prolonged sitting. Too much television has been associated with a long list of problems in kids including obesity, tobacco use, drug and alcohol use, poor achievement in school, and sexual and attention problems.

I'm not against spending a few leisure hours in front of the television. I often watch movies in the evenings, but enjoyable as that can be, it is no substitute for the relaxation techniques that I recommend as the best means of reducing stress, or for the short- and long-term benefits that regular physical activity provide. As we understand more about how moving effects our health, it has become apparent that even small amounts of activity add up in positive ways. Even if your job requires you to be relatively stationary, I encourage everyone to get up and move as much as possible.

Sources:
Daniela Schmid and Michael F. Leitzmann, “Television Viewing and Time Spent Sedentary in Relation to Cancer Risk: A Meta-analysis” Journal of the National Cancer Institute, doi: 10.1093/jnci/dju098

Miguel Martinez-Gonzalez,  “Watching too much TV may increase risk of early death in adults,” Journal of the American Heart Association, June 25, 2014 doi: 10.1161/JAHA.114.000864

Danger at the Nail Salon?

Although it's unlikely, it remains possible that women could develop skin cancer from too much exposure to ultraviolet (UV) light while their nail polish or gel manicures dry, and there have been a few rare case studies where women did develop non-melanoma, squamous cell skin cancer on areas of their hands that were repeatedly exposed to UVA light used in nail salons. To get a better sense of the possible danger, researchers from Georgia Regents University did a random sampling of lamps in 17 nail salons to see how much UV radiation is emitted when nails are drying. They found a wide variation ranging from “barely” to “significant,” said study lead author Lyndsay R. Shipp, but reported nothing to warrant anything more than caution. Previous studies have noted that the exposures to salon lamps are likely not significant contributors to increased risks of skin cancer, and Shipp notes she uses the UV machines at the nail salon every few months and will continue to do so. “You can get that amount of exposure when driving down the road in your car,” she told The New York Times.

Sources:
Deborah F. MacFarlane, and Carol A. Alonso, “Occurrence of Nonmelanoma Skin Cancers on the Hands After UV Nail Light Exposure,” Archives of Dermatology, 2009;145(4):447-449. doi:10.1001/archdermatol.2008.622.

Lyndsay R. Schipp et al, “Further Investigation Into the Risk of Skin Cancer Associated With the Use of UV Nail Lamps,” JAMA Dermatology, doi:10.1001/jamadermatol.2013.8740

What Food Do You Consider Your Greatest Source of Acrylamide? (Poll)

A recent Q&A discussed the dangers of fried foods and the toxic compound called acrylamide: Do Fried Foods Cause Cancer? Check out the article and tell us which food you eat that is the greatest source of acrylamide.

Hops for Hot Flashes, Weight Loss and Cancer Prevention

Researchers at Oregon State University are looking into the cancer protective effects of a flavonoid found in hops, the plants that give beer its bitter flavor. The flavonoid, xanthohumol, can help protect against cancer, at least in cell culture. Investigators at the Linus Pauling Institute at Oregon State have found xanthohumol to be active against breast, colon, and ovarian cancer when these cancer cell lines were grown and treated under lab conditions. The flavonoid might also help prevent prostate cancer. In addition, hops appears to have other health benefits: an extract has been shown to decrease hot flashes in menopausal women, and ongoing studies of the effect of one hops compound may lead to a new approach to weight loss. In animal studies, the compound promoted either outright weight loss or prevented the animals from gaining as much weight as untreated animals. Don’t stock up on beer yet, though, as it doesn’t contain enough xanthohumol to provide any of the potential health benefits. How much xanthohumol would be needed to protect against cancer, control hot flashes and help us lose weight is still being investigated.

Sources:
“An interview with Fred Stevens, Ph.D. Associate Professor of Medicinal Chemistry LPI Principal Investigator,” Linus Pauling Institute Research Newsletter, accessed December 6, 2013, http://lpi.oregonstate.edu/fw10/vitamincbeer.html

“Hops”, Memorial Sloan-Kettering Cancer Center website, accessed December 7, 2013, http://www.mskcc.org/cancer-care/herb/hops

How to Lower Your Breast Cancer Risk

Exercise can help lower a woman’s risk of developing breast cancerWe’ve known for some time that exercise can help lower a woman’s risk of developing breast cancer, and now a large new study suggests that the more a woman exercises, the lower her risk, whether she's overweight or not. The study comes from the American Cancer Society’s Epidemiology Research Program, which had compiled data on more than 73,600 women ages 50 to 73. These women enrolled in the study in the early 1990s and submitted follow-up questionnaires every two years until 2009. The questionnaires delved into the details of what the participants did during their leisure time and how they exercised. Only nine percent reported never exercising. Overall, most of the women listed walking at a pace of three miles per hour as their usual mode of exercise, but some reported more strenuous activity including running, swimming or singles tennis. The researchers found that walking at least seven hours per week (typically once a day) reduced breast cancer risk by 14 percent compared to women who walked less than three hours per week. The most active women, who worked up a sweat while working out for up to 10 hours a week, reduced their breast cancer risk by 25 percent compared to the women who did the least exercise.

My take? This study confirms the conclusions of previous investigations that demonstrated exercise lowered breast cancer risk regardless of a woman’s weight. A study from Germany published in 2008 showed exercise reduced breast cancer risk among women over 50 even more effectively than it did among women age 30 to 49. And a study published in 2003 found that women who don't begin to exercise until later in life can still reduce their breast cancer risk by 20 percent. Here, a brisk, half-hour walk five times a week was enough to lower the risk, even among women with a strong family history of the disease, those who hadn't had children (a long-recognized risk factor), and those who had taken hormone replacement therapy. It also found that 10 hours of exercise per week could cut risk by 30 percent.

Source:
Janet S. Hildebrand, et al, “Recreational Physical Activity and Leisure-Time Sitting in Relation to Postmenopausal Breast Cancer Risk,” Cancer Epidemiology, Biomarkers & Prevention,  doi: 10.1158/1055-9965.EPI-13-0407

Karen Steindorf and Martina Schmidt et al, “Physical Activity and Postmenopausal Breast Cancer: Effect Modification by Breast Cancer Subtypes and Effective Periods in Life,” Cancer Epidemiology, Biomarkers and Prevention, December 2008

Anne McTiernan et al,  “Recreational Physical Activity and the Risk of Breast Cancer in Postmenopausal Women”, Journal of the American Medical Association, September 10, 2003

What’s Your Breast Cancer Risk?

Fewer than one in 10 women accurately estimated their lifetime risk of breast cancerWhatever your view of your breast cancer risk, it’s probably incorrect. A recent survey of nearly 10,000 women revealed that fewer than one in 10 accurately estimated their lifetime risk of breast cancer. About 45 percent of the women participating underestimated their risk, while 46 percent over-estimated it. In general, the survey showed that minority women were more likely to underestimate their odds of developing the disease, while white women overestimated. The women, ages 35-70, completed questionnaires at 21 mammography centers on Long Island, N.Y. They were asked 25 questions about their perceptions of breast cancer risk up to age 90. Results showed that three percent of the women estimated their breast cancer risk to be zero to five percent; 35 percent estimated five to 10 percent; 40 percent of the women estimated 10 to 15 percent; 12 percent put their risk at 15 to20 percent; while five percent estimated 20 to -25 percent and another five percent estimated their risk as greater than 25 percent. "Despite ongoing media attention, awareness campaigns, pink ribbons, breast cancer walks, and breast cancer month, most women lack accurate knowledge of their own breast cancer risk," said Jonathan D. Herman, M.D., of Hofstra North Shore-LIJ Medical School in New Hyde Park, N.Y. who conducted the survey. He is now planning a follow-up study to focus on healthcare providers' understanding about breast cancer risk, and what they think their patients know about their own risk.

My take? The estimates of breast cancer risk uncovered by this survey are pretty wide of the mark. In fact, the average 50-year-old white woman’s five-year risk of breast cancer is 1.3 percent and her lifetime risk (until age 90) is 11.2 percent. If you flip those numbers, you’ll see that for a 50-year-old white woman the odds of not developing breast cancer in the next five years is 98.7 percent and that odds are 88.8 percent against her developing breast cancer in her lifetime. The average five-year risk for mid-life African-American women is 1.2 percent with a lifetime risk of 8.9 percent. You can find breast cancer risk calculators online that can provide a reasonably reliable estimate of your five-year and lifetime risks.

How Alcohol Boosts Breast Cancer Risk in Young Women

Drinking alcohol on a regular basis before a first pregnancy can set the stage for breast cancer later in life.Drinking alcohol on a regular basis before a first pregnancy can set the stage for breast cancer later in life. A study published online on August 28, 2013 in the Journal of the National Cancer Institute found an 11 percent increased risk of breast cancer among women who drank 10 grams (about one-third of an ounce) of alcohol six times a week compared to women who didn’t drink any alcohol. More than 91,000 women participated in the study and were followed for 20 years to determine how drinking (or not drinking) affected their breast cancer risk. None had a history of cancer to start with. The study also linked pre-pregnancy drinking with an increased risk for proliferative benign breast disease, itself a breast cancer risk. The researchers reported that 1,609 women developed breast cancer and 970 developed proliferative benign breast disease over the 20 years. They noted that breast tissue in women who have not been pregnant is particularly susceptible to carcinogens, which they suggested might help explain the breast cancer threat posed by drinking before pregnancy. They also wrote that the increased risk tended to be “more pronounced” among women with a longer time interval between the onset of menstruation and first pregnancy compared with women with a shorter interval.

Source:
Graham Colditz et al, “Alcohol Intake Between Menarche and First Pregnancy: A Prospective Study of Breast Cancer Risk,” Journal of the National Cancer Institute, doi: 10.1093/jnci/djt213 First published online: August 28, 2013

How to Prevent a Common Cancer

Healthy diet, keeping weight down and regular exercise can protect women from endometrial cancer.A healthy diet (that includes a daily cup of coffee), keeping weight down and regular exercise can protect women from endometrial cancer, the most common malignancy affecting the female reproductive organs (the endometrium is the lining of the uterus). A new study from the American Institute for Cancer Research (AICR) and World Cancer Research Fund International found that keeping weight down via diet and exercise could prevent almost 60 percent of the 49,600 new cases of endometrial cancer that occur annually in the United States. The antioxidants in coffee (both regular and decaf) can cut the risk by seven percent, possibly by preventing DNA damage, improving insulin sensitivity and inhibiting glucose absorption in the intestine. Avoiding high glycemic index foods is also key. The study found that for every 50 units of glycemic load that a woman averages in her daily diet, the risk of endometrial cancer bumps up 15 percent. And they noted that foods high on the glycemic index affect production of estrogen and insulin, the hormones thought to underlie endometrial cancer. Bottom line: obesity is likely the primary driver of endometrial cancer, as body fat produces estrogen, which stimulates the uterine lining.

Source:
“New Report: In the U.S., 3 out of 5 Cases of Endometrial Cancers are Preventable,” American Institute for Cancer Research and World Cancer Research Fund International, accessed September 13, 2013, http://www.aicr.org/press/press-releases/3-out-of-5-cases-of-endometrial-cancer-are-preventable.html