Maintaining a Normal Weight BMI <25 kg/m2 Reduced Risk of Breast Cancer in Women This recommendation was not listed out of thin air by the Big Three, but is based on the results of several recent randomized clinical trials. To prevent breast cancer, the ACS recommends that women get at least 150 minutes of moderate-intensity exercise per week, drink up to one standard drink of alcoholic beverages per day, and maintain a body mass index (BMI) of less than 25 kg/m2. In one clinical trial (2,905 women), women who were at high risk for developing breast cancer reduced their risk of developing the disease by 44 percent by following the ACS recommendations. The Women's Health Initiative Watch (64,000 women) found that eating a healthy diet (more fruits and vegetables, less meat, and less alcoholic beverages) significantly reduced the risk of breast cancer in women: by 20% for women with a BMI <25 kg/m2 and by 30% for women with a BMI = 25-29.9 kg/m2. You should note that a healthy diet did not reduce the risk of breast cancer in obese women. You may not be surprised to hear that high BMI is a cancer risk factor in itself. Excess body fat triggers insulin resistance, and elevated levels of insulin and growth factors promote cancer. Obesity also promotes estrogen production, which in turn is a stimulus for many cancers. In addition, fat secretes cytokines that promote inflammation. A recent meta-analysis of 50 prospective observational studies found that maintaining a normal body weight in adults may prevent certain specific types of cancer, especially those for which hormone replacement therapy (HRT) is not indicated. For example, for every 5 kg increase in body weight in adult women, their relative risk of postmenopausal breast cancer increased by 11%, postmenopausal endometrial cancer by 39%, and postmenopausal ovarian cancer by 13%. The key issue is that adult weight increases with age, and there is no defense against this. So the only thing you can do is to manage your health. Increased Physical Activity MET=7.5-15, Reduced Risk of Cancer Death Several observational studies have found that physical activity reduces the risk of breast, colorectal, and endometrial cancers. A study of U.S. and European populations found a 20 percent lower risk of cancer death among those who exercised at the minimum recommended level of physical activity - 7.5-15 metabolic equivalents per week (MET) - compared with those who did not exercise. At this year's ASCO Annual Meeting, Professor Abrams of the University of California noted that exercise improves the prognosis for cancer patients after diagnosis. A recent meta-analysis of breast and colorectal cancer survivors (50,000 patients) also showed that being physically active reduced breast and colorectal cancer mortality in survivors. More vegetables, less meat? Eating Lean Meat Isn't So Bad A recent meta-analysis study found that eating more fruits and vegetables reduces all-cause mortality and cardiovascular mortality in people, but is not associated with cancer-related mortality. In addition, the study found that lean meat isn't as bad as we thought, at least from a cancer risk perspective. According to the European Prospective Investigation into Cancer and Nutrition (EPIC), the main concern was whether processed meat products (e.g., canned meat, sausages) increased the risk of cancer. The study found that an additional 50g of processed meat products per day was associated with an 11% higher risk of cancer. However, lean meat was not associated with cancer risk. Therefore, processed meat products deserve more attention than lean meat. Drinking alcohol in moderation 1 standard drink per day and no more Heavy drinking (more than 5 standard drinks per day) is significantly associated with the development of 10 types of cancers: oropharyngeal, esophageal squamous, breast, laryngeal, colorectal, liver, stomach, gallbladder, pancreatic, and lung cancers. In addition, a small amount of alcohol (1 standard drink per day) has been found to increase the risk of oropharyngeal, esophageal squamous epithelial, and breast cancers. However, recent studies have reported that moderate alcohol consumption can prevent cancer. In addition, we cannot ignore the fact that non-drinking is associated with overall mortality, as cardiovascular morbidity tends to be higher in non-drinkers, so we cannot just advocate "abstaining from alcohol is good for your health". Don't mess around with vitamin supplements Don't take vitamin supplements if you don't have them A recent randomized clinical trial examined whether consumption of vitamin supplements in healthy populations could reduce the risk of cancer. However, the study had some sobering results: (1) folic acid increased the risk of cancer, especially prostate and colorectal cancers; (2) beta-carotene increased the risk of lung and stomach cancers; (3) selenium increased the risk of non-melanoma skin cancers; and (4) vitamin E increased the risk of prostate cancer. In summary, obesity, lack of exercise and excessive alcohol intake are all risk factors for cancer development and should be emphasized. However, dietary habits may not be a risk factor for cancer development, at least according to current evidence.