2016 FEB - Non-Medicated Life
Reducing Cancer Risk
By Paul E. Lemanski, MD, MS, FACP
Editor’s Note: This is the 69th in a series on optimal diet and lifestyle to help prevent and treat disease. Any planned change in diet, exercise or treatment should be discussed with and approved by your personal physician before implementation. The help of a registered dietitian in the implementation of dietary changes is strongly recommended.
Medicines are a mainstay of American life and the healthcare system not only because they are perceived to work by the individual taking them, but also because their benefit may be shown by the objective assessment of scientific study. Clinical research trials have shown that some of the medicines of Western science may reduce the risk of heart attacks, strokes and cardiovascular death while others may reduce certain types of cancer.
In the first 68 installments of the Non-Medicated Life, informed diet and lifestyle have been shown to accomplish naturally for the majority of individuals, many, if not most of the benefits of medications in the prevention and treatment of chronic medical conditions. Moreover, informed diet and lifestyle as a medical intervention may accomplish such benefits at lower risk for side effects and at a lower cost. However, when addressing the challenge of reducing cancer risk, diet and lifestyle are perhaps two of the most powerful means by which one may help reduce risk and improve outcome.
It has been estimated that up to 50% of cancer is preventable. A number of risk factors for cancer have been identified, but several stand out as the major contributors including tobacco use, excess body weight, alcohol consumption, lack of exercise, and an unhealthy diet. I will take each in turn.
Tobacco – The leading cause of preventable cancer deaths remains the use of tobacco, which accounts for 30% of all cancer related deaths. Smoking cigarettes increases the risk of cancers of the mouth, tongue, throat, voice box, esophagus, stomach, pancreas, kidney, cervix, bladder and prostate. Additionally, the use of cigars, pipes and smokeless tobacco also increases this risk.
Body Weight – Another leading cause of preventable cancer deaths rivaling tobacco is excess body weight. Overweight and obesity have been estimated to account for 20% of all cancer related deaths. Excess body weight is associated with cancers of the lining of the uterus, thyroid, kidney, colon, postmenopausal breast and prostate. Bariatric surgery, which most consistently reduces excess body weight over a protracted time line, has been shown to decrease cancer mortality by 60%, and reduce the risk of breast cancer.
Alcohol – A third leading cause of preventable cancer related deaths is excess consumption of alcohol. Alcohol contributes to cancers of the oral cavity, tongue, voice box, esophagus, liver and breast. Surprisingly, in women, even what many consider to be moderate drinking – one drink per day – was shown to increase the risk of breast cancer. In one study in European men, alcohol accounts for up to 10% of the attributable risk for any cancer.
Exercise – A fourth leading cause of preventable cancer related deaths is lack of physical exercise. Up to 5% of all cancer deaths may be attributable to lack of exercise. The data is most compelling with breast cancer, and colon cancer, but also to a lesser extent with cancer of the lining of the uterus, and with prostate cancer. In a meta-analysis, comparing the results of 52 separate studies, those who were most active were 24% less likely to develop colon cancer than those least active. In another meta-analysis of 20 studies, regular exercise decreased the risk of developing colon polyps, the precursor to colon cancer, by 15%. Moreover, the effects of regular exercise on reducing the risk of colon cancer and breast cancer appear not to be simply a result of an exercise mediated reduction in body weight.
Diet – Finally, a poor or unhealthy diet has been associated with an increase in certain cancers. For example, an increase in the consumption of red meat especially processed meats increases the risk for colorectal cancer and prostate cancer. In one meta-analysis of 10 studies, 100 grams per day of red meat increased colorectal cancer by 17%, and 50 grams per day of processed meats increased cancer risk by 18%. The exact mechanism of the increased risk is not clear, but carcinogens called heterocyclic aromatic amines are produced by high temperature cooking of red meat, and these may contribute to the risk.
On the basis of the risks described above, a reduction in the risk for cancer may be accomplished by a straightforward alteration in lifestyle and diet. First, all tobacco products need to be eliminated. This would include not just cigarettes but cigars, snuff and chewing tobacco. Secondary smoke should be avoided. While one is attempting to quit and for an appropriate time afterward, a careful screening of the mouth, tongue, voice box, bladder, cervix and prostate is important. This exam may be started by a primary care physician, but also aided by one’s dentist, ENT physician, gastroenterologist, gynecologist and urologist.
Likewise, a reduction in the risk for cancer may benefit from a reduction in body weight. A family history of those cancers associated with excess body weight may serve as special motivation to reduce one’s own excess weight and thus risk. Until the weight reduction is accomplished, and for an appropriate time afterward, a primary care physician can direct his or her physical exam and simple lab tests to a careful screening for those cancers associated with obesity. For those morbidly obese and unable to lose weight over a protracted time, bariatric surgery may be considered.
Alcohol consumption should be moderated especially in women. Those women with a family history of breast cancer should consider avoiding alcohol completely. Men with a history of premalignant conditions of the mouth, tongue, and esophagus should likewise strongly consider all discontinuation of alcohol. Certainly, careful follow-up and regular exams with one’s primary care physician, gynecologist, and specialist would be prudent as well.
Daily physical exercise involving walking or some similar aerobic activity would also be a simple way to decrease cancer risk. For those who are too busy to go to the gym, a pedometer can help quantify daily activity. As long as not limited by arthritis or other medical conditions, an individual slowly working up to walking 10,000 steps a day is one way to ensure both adequate daily exercise, and control of body weight. Once a baseline number of steps is established, it then becomes clearer what additional steps are needed. Walking 15 minutes before breakfast, lunch and dinner for many is a doable way to increase steps per day with the least adverse impact on your schedule.
Finally, eating a predominantly plant based diet rich in legumes, vegetables and minimally-processed grain, will help you feel full and minimize the need for the excess consumption of meat. Avoiding processed meats all together is probably best.
In these ways it may be possible to use diet and lifestyle to reduce the risk for cancer. Combined with appropriate screening tests for cancer done by your primary care physician, such an approach can go a long way to preventing cancer, or at least identifying it in early more curable stages – which afford a better long term outcome.
Paul E. Lemanski, MD, MS, FACP (firstname.lastname@example.org) is a board certified internist at the Center for Preventive Medicine, CapitalCare Medical Group in Albany. He is medical director of the Department of Community Medicine and Population Health at CapitalCare Medical Group. Paul has a master’s degree in human nutrition; he is an assistant clinical professor of medicine at Albany Medical College and a fellow of the American College of Physicians.