Should doctors prescribe exercise?

“Although the data vary by different cancer types, there is a consistent trend suggesting that moderate daily exercise has a beneficial effect on preventing certain cancers. If you are a reasonably healthy adult, your should exercise regularly.” 

Let’s look at the relationship of exercise and selected cancers. The American Society of Clinical Oncology (ASCO) has done a nice job of summarizing:

Breast Cancer

While the amount of risk reduction varies among studies (20-80%), most suggest that 30 to 60 minutes of moderate to high-intensity exercise per day lowers breast cancer risk. Women who are physically active throughout their life appear to benefit the most, but those who increase physical activity after menopause also fare better than inactive women.1

Colon Cancer

Research suggests that people who increase their physical activity can lower the chance of developing colon cancer by 30 to 40% relative to sedentary adults.1,2 A decrease in colon cancer risk can be achieved regardless of body mass index (BMI) and people who are most active benefit the most. There is insufficient evidence of a protective effect of physical activity on the risk of rectal cancer (a protective effect was seen in some case-control studies, but not in cohort studies).3

Endometrial, Lung and Ovarian Cancer

A handful of studies have suggested that women who are physically active have a 20-40% reduced risk of endometrial cancer compared to those who don’t exercise.1 Higher levels of physical activity seem to also protect against lung cancer (up to 20% reduction in risk), particularly among men.1Although less consistent, research suggests that physical activity possibly reduces the risk of ovarian and prostate cancer.

What about Other Cancers?

While observational data on the benefits of exercise for prevention of the types of cancers listed above are fairly consistent, evidence of the effects of exercise on prevention of any other type of cancer either is either insufficient or inconsistent.2,4

Prostate Cancer

Prostate cancer is one disease in which the data are not consistent, however prostate cancer is a heterogeneous disease and risk factor associations for total non-aggressive disease are different from aggressive / lethal disease. Most population based studies show similar findings, with little effect of exercise on overall incidence of prostate cancer but lower risk of aggressive prostate cancers for those with the highest levels of VIGOROUS activity (rather than any type of activity). In the Health Professionals Follow-up Study men 65 years or older who engaged in vigorous physical activity, such as running, jogging, biking, swimming or tennis at least three hours per week  had a 67% lower risk of advanced prostate cancer and 74% lower risk of fatal prostate cancer.5

Conflicting data for other malignancies

For example, one recent study found no association between physical activity and risk of developing gastric, rectal, pancreatic, bladder, testicular, kidney and hematological cancers.4 In contrast, a pooled analysis of data from prospective trials with 1.4 million participants found that physical activity was linked to lower risk of 13 cancers: esophageal, lung, kidney, gastric, endometrial, myeloid leukemia, myeloma, colon, head and neck, rectal, bladder, and breast.6Interestingly, leisure-time physical activity was associated with a higher risk of melanoma (presumably due to time spent outdoors) and prostate cancer, although it is not clear from these data whether that association was with nonaggressive or aggressive prostate cancer.

While we wait for confirmation and clarity on the role of exercise in preventing all the 200+ types of cancer – should doctors prescribe exercise? The answer is simple: yes, because evidence of the protective role of exercise is already strong for some of the most common cancers.

References

  1. Lee I, Oguma Y. Physical activity. In: Schottenfeld D, Fraumeni JF, editors. Cancer Epidemiology and Prevention. 3rd ed. New York: Oxford University Press, 2006.
  2. Slattery, ML. Physical activity and colorectal cancer. Sports Medicine 2004; 34(4): 239–252.
  3. Pham NM, et al. Physical activity and colorectal cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population. Jpn J Clin Oncol. 2012 Jan;42(1):2-13.
  4. Friedenreich CM, Neilson HK, Lynch BM. Eur J Cancer. State of the epidemiological evidence on physical activity and cancer prevention. 2010 Sep;46(14):2593-604.
  5. Giovannucci E, Liu Y, Leitzmann MF, et al. A prospective study of physical activity and incident and fatal prostate cancer. Arch Intern Med. 2005; 165(9):1005-1010.
  6. Moore SC, Lee IM, Weiderpass E, et al. Association of Leisure-Time Physical Activity With Risk of 26 Types of Cancer in 1.44 Million Adults. JAMA Intern Med. 2016 Jun 1;176(6):816-25.
  7. http://www.asco.org/about-asco/press-center/asco-resources-media/cancer-perspectives/should-cancer-doctors-prescribe?et_cid=38723632&et_rid=463715101&linkid=Read+more

I’m Dr. Michael Hunter. Of course, the disclaimer: Do not begin an exercise program without input from an appropriate medical professional. Many can simply start with a brisk walk for 30 minutes daily, 5 days per week. Have a wonderful day!

Too High levels of Vitamin D May Increasing Mortality

What You Need to Know: The level of vitamin D in our blood should neither be too high nor too low. Scientists from the University of Copenhagen are the first in the world to show that there is a connection between high levels of vitamin D and cardiovascular deaths.

The Study: Several studies have shown that too low vitamin D levels can prove detrimental to our health. However, new research from the University of Copenhagen reveals, for the first time, that too much vitamin D in our blood is connected to an increased risk of dying from a stroke or a heart attack.

“We have studied the level of vitamin D in 247,574 Danes, and so far, it constitutes the world’s largest basis for this type of study. We have also analysed their mortality rate over a seven-year period after taking the initial blood sample, and in that time 16,645 patients had died. Furthermore, we have looked at the connection between their deaths and their levels of vitamin D,” Professor at the Department of Clinical Medicine, Peter Schwarz explains.

Conclusion: Dr. Schwartz concludes: “If your vitamin D blood level is below 50 or over 100 nanomol per litre, there is an greater connection to deaths. We have looked at what caused the death of patients, and when numbers are above 100, it appears that there is an increased risk of dying from a stroke or a coronary. In other words, levels of vitamin D should not be too low, but neither should they be too high. Levels should be somewhere in between 50 and 100 nanomol per litre, and our study indicates that 70 is the most preferable level,” Peter Schwartz states.

My Take: There is a correlation between mortality rates and too low levels of vitamin D, but the new findingis that the levels of vitamin D that are too high may be linked to cardiovascular risk. As is the case with so many things, moderation may be the key. I’m Dr. Michael Hunter.


The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

References:

  • D. Durup, H. L. Jørgensen, J. Christensen, P. Schwarz, A. M. Heegaard, B. Lind. A Reverse J-Shaped Association of All-Cause Mortality with Serum 25-Hydroxyvitamin D in General Practice: The CopD Study. The Journal of Clinical Endocrinology & Metabolism, 2012; 97 (8): 2644 DOI: 10.1210/jc.2012-1176
  • University of Copenhagen – The Faculty of Health and Medical Sciences. “High levels of vitamin D is suspected of increasing mortality rates.” ScienceDaily. ScienceDaily, 10 March 2015. <www.sciencedaily.com/releases/2015/03/150310105222.htm>.

How Can You Reduce Your Risk of Getting Cancer?

Recent reports suggest that about 2 out of 3 cancers may be due to “bad luck.” Today, we focus on the other third: What can you do to reduce your risk of cancer?

What You Need to Know:

  • Maintaining a healthy body weight and being physically active had the greatest impact on overall risk of a cancer-related death. 
  • Restricting alcohol consumption to one drink per day for women and two drinks per day for men was associated with 29% reduced risk for obesity-related cancers. Additionally, the risk was up to 71% lower for the most common site-specific cancers in the United States (breast, prostate, and colorectal).

Background

  • As people make their resolutions for 2015, two new studies — which show that curbing alcohol consumption, adding more plant foods to the diet, and losing excess weight can help reduce the risk of developing cancer — serve as a reminder that a healthy lifestyle is important.
  • In 1997, the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR) issued cancer prevention guidelines for weight management, diet, and physical activity. These were updated in 2007 and are considered to be the most comprehensive scientific analysis of cancer prevention and causation ever undertaken. Specifically, the guidelines reported that excess body fat is associated with an increased cancer risk and that there is convincing evidence that the consumption of alcohol, red meat, and processed meat elevates cancer risk. Since that time, numerous studies have reported links between colorectal cancer risk and alcohol, between breast cancer mortality and obesity, between breast cancer relapse and obesity, and between breast cancer risk and red meat.

The Evidence: The first study, published online January 6 in Cancer Causes & Control, showed that eating a plant-based diet and limiting alcohol intake, both already included in various cancer prevention guidelines, could help cut the risk for obesity-related cancers (about a third of all of cancers). In a cohort of nearly 3000 adults, the researchers found that restricting alcohol consumption to one drink per day for women and two drinks per day for men was associated with 29% reduced risk for obesity-related cancers. Additionally, the risk was up to 71% lower for the most common site-specific cancers in the United States (breast, prostate, and colorectal). For individuals who consume starchy vegetables, such as corn, potatoes, and yams, sufficient consumption of nonstarchy legumes, fruits, and vegetables was associated with a reduction in the risk for colorectal cancer.

Pronounced Effect on Cancer Risk

In their study, Makarem and colleagues investigated whether the healthful behaviors outlined in the WCRF/AICR guidelines were associated with the risk for obesity-related cancers, in particular, breast, prostate, and colorectal cancer. Of the 2983 adults enrolled in the Framingham Offspring cohort from 1991 to 2008, the researchers identified 480 incident obesity-related cancers.

Data from food frequency questionnaires, anthropometric measures, and self-reported physical activity were used to develop a 7-component score based on recommendations for body fatness; physical activity; foods that promote weight gain; plant foods; animal foods; alcohol; and food preservation, processing, and preparation. The cohort was, on average, middle aged to older and overweight, but had a relatively high level of physical activity. The mean duration of follow-up was 11.5 years.

The overall score was not associated with obesity-related cancer risk after adjustment for confounders such as age, sex, smoking, energy, and pre-existing conditions (hazard ratio [HR], 0.94; 95% confidence interval [CI], 0.86 – 1.02). However, when the score components were considered separately, the researchers found that for every unit increment in the alcohol score (representing an improvement and more closely meeting the guideline recommendations), there was 29% lower risk for obesity-related cancers (HR, 0.71; 95 % CI, 0.51 – 0.99) and a 49% to 71% reduced risk for breast, prostate, and colorectal cancers.

Similarly, each unit increment in the subcomponent score for nonstarchy plant foods (fruits, vegetables, and legumes) for those who eat starchy vegetables was associated with a 66% lower risk for colorectal cancer (HR, 0.44; 95% CI, 0.22 – 0.88).

Healthy Body Weight and Exercise Reduce Mortality

The second study, published online January 7 in the American Journal of Clinical Nutrition, reported similar results. Researchers found that greater adherence to the cancer prevention guidelines of the American Cancer Society (ACS) was associated with a reduction not only in cancer incidence, but also in cancer mortality and total mortality.

The ACS guidelines recommend that individuals avoid smoking, achieve and maintain a healthy weight, be physically active, and eat a healthy diet that emphasizes plant foods. In their study, Geoffrey Kabat, PhD, senior epidemiologist in the Department of Epidemiology & Population Health at the Albert Einstein College of Medicine in Bronx, New York, and colleagues report that maintaining a healthy body weight and being physically active had the greatest impact on overall mortality for both men and women.

The researchers used data from the NIH-AARP Diet and Health Study, a prospective cohort study of 566,401 adults who were 50 to 71 years of age in 1995 and 1996, when they enrolled in the study. They were followed for a median of 10.5 years for cancer incidence, 12.6 years for cancer mortality, and 13.6 years for total mortality.

During the study period, there were 73,784 cases of cancer, 16,193 cancer deaths, and 81,433 deaths from any cause. The patients were stratified by how closely they adhered to ACS guidelines, and adherence to the guidelines was associated with a reduced risk for all cancers combined. When the highest level of adherence was compared with the lowest level, the hazard ratio was 0.90 for men and 0.81 for women.

In addition, increased adherence was associated with a reduction in risk for 14 of 25 specific cancers. Reduction in the risk for gallbladder cancer was 65% in men and women combined, for endometrial cancer was 60%, for liver cancer was 48% in men, for colon cancer was 48% in men and 35% in women, and for rectal cancer was 40% in men and 36% in women.

My Take: These results add to the existing evidence on the potential role of limiting alcohol intake and increasing the intake of plant foods in influencing cancer risk. Dietary advice on cancer should focus on encouraging the consumption of a plant-based diet providing abundant non-starchy fruits, vegetables, and legumes, and restricting alcohol, if consumed at all, to the recommended levels. Try to stick to the ACS Guidelines, as the closer you follow them, the greater the benefit in cancer risk-reduction. Finally, exercise and don’t use tobacco. I’m Dr. Michael Hunter.

References: Cancer Causes Control. Published online January 6, 2015. Abstract; Am J Clin Nutr. Published online January 7, 2015. Abstract; http://www.medscape.com/viewarticle/837976#vp_2

Do Apples and Berry Fruits Reduce Colon Cancer Risk?

Background: Colon cancer arises due to the conversion of precancerous polyps (benign) found in the inner lining of the colon.

  • Prevention is better than cure, and this is very true with respect to colon cancer.
  • Various epidemiologic studies have linked colorectal cancer with food intake.
  • Apple and berry juices are widely consumed among various ethnicities because of their nutritious values.

My Take: This thorough literature review suggests that various phenolic phytochemicals present in these fruit juices have the potential to inhibit colon cancer cell lines. We need more research on the use of diet to reduce cancer risk. In the meantime, eat those fruits and vegetables! I’m Dr. Michael Hunter.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

Available now: Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Both can be found at the Apple Ibooks store. Coming Soon for iPad: Understand Breast Cancer in 60 Minutes; Understand Colon Cancer in 60 Minute; Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Thank you.

Reference: World Journal of Gastroenterology, 12/26/2014  Review Article

Is Low Vitamin D Linked to a Higher Death Risk?

What You Need to Know: A new study, using a new technique called Mendelian randomization, provides persuasive evidence that low serum vitamin D itself increases the risk of death.

Background: Many observational studies suggest that low vitamin D levels are associated with an increased risk for disease, but it is not clear if low vitamin D is a cause or an effect of poor health.

The Study: Researchers used data from Danish government health records on 95,766 subjects. All were tested for a genetic variant that reduces their vitamin D levels, and 35,334 also had their vitamin D serum levels measured. There were 10,349 deaths over the course of the study, from 1981 to 2013.

Results: Having the genes associated with lifelong vitamin D increases the risk of cancer death by more than 1.4x, and death from any cause by more than 1.3x.

My Take: This study shows there may be a causal relationship between low vitamin D levels and death. Still, this study is not sufficient to recommend that you go out and buy supplements. We need randomized trials to recommend that. For me personally, I have no issues with taking 2000 IU of vitamin D daily. Whether I can modify my disease risk by doing so, however, is speculation. Sunshine is a remarkably efficient way to make vitamin D, but don’t overdo (We don’t need you getting skin cancer)! I’m Dr. Michael Hunter.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

Available now: Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Both can be found at the Apple Ibooks store. Coming Soon for iPad: Understand Breast Cancer in 60 Minutes; Understand Colon Cancer in 60 Minute; Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Thank you.

Reference: BMJ 2014; 349 doi: http://dx.doi.org/10.1136/bmj.g6330 (Published 18 November 2014)

Lower Your Breast Cancer Recurrence Risk

What You Need to Know: Patients with breast cancer who reduced their dietary fat intake for 5 years after a diagnosis of hormone-unrelated early-stage breast cancer had signficantly reduced all-cause death rates, according to data from the Women’s Intervention Nutrition Study (WINS) presented at the 2014 San Antonio Breast Cancer Symposium.

The Study: For WINS, a randomized trial, Dr. Chlebowski and colleagues recruited 2,437 women ages 48 to 79 years with early-stage breast cancer receiving standard-of-care treatments at 39 centers in the United States. Of them, 1,597 had ER-positive breast cancer, 478 had ER-negative breast cancer, and 362 had ER/PR-negative breast cancer. Within 6 months of diagnosis, subjects were randomly assigned either to a dietary intervention group (n=975; 205 with negative cancer, and 147 ER/PR-negative cancer) or to a control group (n=1,462; 273 ER-negative cancer, and 215 ER/PR-negative cancer).

The dietary intervention was centered on a goal of lowering fat intake for 5 years while maintaining nutritional adequacy. Centrally trained, registered dieticians implementing a low-fat eating plan, gve women in the intervention group a fat gram goal, and the women underwent 8 biweekly individual counseling sessions with subsequent contacts every 3 months. Subjects also self-monitored their fat/gram intake using a “keeping score” book. Fat intake was externally monitored by unannounced annual 24-hour telephone recalls done.

“The current findings with respect to long-term influence of dietary lifestyle intervention on overall survival are mixed, but of potential importance,” said Rowan Chlebowski, MD, PhD, medical oncologist at the Los Angeles Biomedical Research Institute at the Harbor-UCLA Medical Center. “In a prior report of WINS after 5-years’ follow-up, relapse events were 24% lower in the intervention group. In the current report, the intervention influence on long-term survival was examined. Overall, while the death rate was somewhat lower in the intervention group compared with control group (13.6% versus 17%, respectively), the difference was not statistically significant. However, in exploratory subgroup analyses, in women with estrogen receptor [ER]-negative cancers, a 36 percent, statistically significant reduction in deaths was seen in women in the intervention group,” said Dr. Chlebowski.

  • In women with cancers that were both ER- and progesterone receptor [PR]-negative, the reduction was even more significant (56%), Dr. Chlebowski added.
  • After 5 years of dietary intervention, researchers found that fat calories were lowered by 9.2% and body weight was lowered by nearly 6 pounds in the intervention group, compared with the control group.

“HER2 evaluation was not available when this study was conducted, but it is likely that a substantial number of ER/PR-negative breast cancers were also negative for HER2, making them triple-negative breast cancers, which generally have a poor prognosis,” said Dr. Chlebowski. “The signal that perhaps a lifestyle intervention targeting dietary fat intake associated with weight loss could substantially increase the chances of survival for a woman with triple-negative breast cancer could influence this group of patients.”

My Take: It is wonderful that we have an increasing body of evidence that dietary manipulation may lower your risk of recurrence. The drop is not small: It is more than half for those whose tumors are not driven by either estrogen or progesterone. In addition, you may lower your risk of heart attack, stroke, other cancers, and a myriad of other medical problems. Researchers in this study supported the dietary intervention for a median of 5 years. Aim for a lifelong change rather than be a short-term alteration in your diet. I’m Dr. Michael Hunter.

Reference: 37th San Antonio Breast Cancer Symposium (December, 2014); San Antonio, TX

Mediterranean Diet has Marked Impact on Aging

Background: The Mediterranean diet consistently has been linked with an array of health benefits, including decreased risk of chronic disease and cancer. Until now, however, no studies had associated the diet with longer telomeres, one of the biomarkers of aging.

Telomeres are repetitive DNA sequences at the ends of chromosomes that get shorter every time a cell divides. Shorter telomeres have been associated with decreased life expectancy and increased risk of aging-related disease (including cancer), while longer telomeres have been linked to longevity. Telomere shortening is accelerated by stress and inflammation, and scientists have speculated that adherence to the Mediterranean diet may help protect against that effect.

The Evidence: In a study published Tuesday online in The British Medical Journal, researchers at Harvard-affiliated Brigham and Women’s Hospital (BWH) found that greater adherence to the Mediterranean diet correlated with longer telomeres.

“To our knowledge this is the largest population-based study specifically addressing the association between Mediterranean diet adherence and telomere length in healthy, middle-aged women,” explained Immaculata De Vivo, an associate professor in the Channing Division of Network Medicine at BWH and the Harvard T.H. Chan School of Public Health, the senior author of this study. “Our results further support the benefits of adherence to this diet to promote health and longevity.”

The researchers analyzed 4,676 disease-free women from the Nurses’ Health Study who had completed the food-frequency questionnaire and whose telomere lengths had been measured. They found that a greater adherence to the Mediterranean diet was associated with longer telomeres, and that even small changes in diet made a difference.

“Our findings showed that healthy eating, overall, was associated with longer telomeres. However, the strongest association was observed among women who adhered to the Mediterranean diet,” explained Marta Crous Bou, a postdoctoral fellow in the Channing Division of Network Medicine and the first author of the study.

De Vivo notes that future research should be aimed at determining which components of the Mediterranean diet drive this association. This would allow researchers to gain insight into the biological mechanism, as well as provide a basis for increased public education for informed lifestyle choices.

My Take: How wonderful that we may be able to slow the aging clock with a healthy diet. But don’t forget physical activity (such as a brisk walk for 30 minutes, 5 times per week), as it too may slow telomere shortening and add to your life expectancy and overall health. I’m Dr. Michael Hunter. Ciao!

Reference: Harvard Gazette 02 December 2014