Page 70 Complete Your CE Test Online - Click Here Outside of the workplace, most people can take steps to limit their exposure to known carcinogens, such as: ● ● Testing basements for radon. ● ● Avoiding tobacco smoke and tobacco use. ● ● Reading labels before using chemicals and substances (for example, some common insecticides and herbicides were upgraded in 2015 to “possibly” or “probably” carcinogenic in humans by the IARC [107]). ● ● Limiting UV exposure. ● ● Maintaining a healthy weight [161]. ● ● Limiting alcohol intake. Dietary and exercise recommendations for cancer prevention The National Cancer Institute reports that the evidence for influence of dietary factors and cancer is uncertain. There is difficulty evaluating the impact of diet on cancer risk because while lifelong dietary patterns or dietary intake during specific life stages may be important in cancer development, they are not likely detected by relatively short- term randomized clinical trials [148]. Attempts to quantify the role of diet have been based on systematic reviews of epidemiologic evidence, which found that the greatest consistency was seen for non-starchy vegetables and fruits [227,305]. These were linked to probable decreased risk for upper GI cancers. Fruits were also linked to a probable decreased risk for lung cancer. In relation to human cancer, diets reflect the sum total of a complex mixture of exposures. No dietary factors appear to be uniformly relevant to all forms of cancer [148]. Nevertheless, the American Cancer Society has specific dietary and physical activity recommendations. The following are adapted from American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention [115]: 1. Maintain a healthy weight. ○ ○ Stay lean without being underweight. ○ ○ Avoid excess weight gain. If currently overweight or obese, start by losing small amounts. ○ ○ Use regular exercise and limit high-calorie foods to reach or maintain a healthy weight. 2. Cultivate physically active habits. ○ ○ Each week, adults should exercise at least 150 minutes at moderate intensity or 75 minutes at vigorous intensity or equivalent, spread throughout the week if possible. ○ ○ Teens and children should exercise at least one hour (moderate or vigorous intensity) each day, with vigorous intensity on at least three days of the week. ○ ○ Limit time spend sitting, reclining, watching TV and other electronic screens. 3. Eat a healthy diet that emphasizes plant foods. ○ ○ Limit intake of processed meats (e.g. bacon, bologna, sausage, luncheon meats, hot dogs, cured meats) and red meats (e.g. beef, pork, lamb). ○ ○ Eat five servings (about 2.5 cups total) of a variety of vegetables and fruits every day. ○ ○ Choose whole grains instead of foods with refined grains and high sugar content. Of course, there is no guarantee that any or all of these measures will prevent any one person’s cancer, but as public health measures, they should reduce cancer risk overall. Dietary supplements for cancer prevention Patients and family will often inquire what they can “take” to prevent cancer. They might want to know about dietary supplements because they are interested in a “natural” approach to health. But dietary supplements are a broad category that can include vitamins and minerals, herbs, or botanicals (products made from plants). Others supplements are made from animal parts, algae, yeasts, fungus, or seafood, among many other things [22]. Some dietary supplements have been shown to be beneficial for certain health conditions. For example, folic acid supplements used by women of childbearing age who may become pregnant reduces the risk of some birth defects. Another example is crystalline vitamin B12, which helps people over age 50, a time when many have a reduced ability to absorb naturally occurring vitamin B12 from foods [281]. While many herbal supplements are carefully grown, tracked, harvested, and prepared under clean controlled conditions, there are others that are not. Many supplements sold today have fillers and contaminants that are not on the label. Supplements have had to be recalled by the FDA because of proven or potential harmful effects. Reasons for these recalls include [281]: ● ● Microbiological, pesticide, and heavy metal contamination. ● ● Absence of a dietary ingredient claimed to be in the product. ● ● The presence of more or less than the amount of the dietary ingredient claimed on the label. Although some may find it disappointing, there is nothing inherently safe about “natural” plants and animal parts unless they are well understood, carefully prepared, and properly used. Some of the most toxic substances and potent allergens in the world occur naturally [22]. Hemlock and poison mushrooms are natural but are quite dangerous if taken internally. There have been some concerns about the content of many herbal preparations sold in the U.S. When herbal supplements have been purchased and tested by researchers, many of them have been found to contain contaminants or fillers. Some supplements did not contain any of the substances listed on their labels, which in 2015 led to legal action by the state Attorney General of New York [225,226]. One major supplement retailer signed an agreement to authenticate supplements and adopt new standards as a result [224]. Unfortunately, a few manufacturers produce so-called “natural” supplements that are covertly adulterated with actual drugs that are known to have harmful side effects. For example, many weight loss products and “men’s supplements” contain prescription drugs (for example, sibutramine, anabolic steroids, tadalafil), some of which have been banned by the FDA because they were harmful to human health [76]. In fact, according to the IARC, androgenic (anabolic) steroids are probable carcinogens [32]. It is also important for patients to know that dietary supplements do not have to prove effectiveness or safety before being marketed; they are considered safe until proven otherwise. The U.S. FDA regulates food supplements like food because it expects them to have no more effect than food does. The FDA also regulates claims that can be made by supplement sellers as well as the types of materials that are allowed in the supplements, but laws are sometimes broken [22]. Based on the evidence about nutrition and dietary supplements, the American Cancer Society advises that it is better to eat healthy foods to obtain antioxidants and vitamins rather than take them as supplements. No dried supplement is equivalent to eating whole foods, fruits, and vegetables. Food is the best source of vitamins and minerals [115]. Most vitamins and other supplements do not cause problems in normal doses, but high doses of supplemental vitamin E (taken alone), in one study, were linked to a slightly higher rate of prostate cancer in men who had lower levels of selenium in the body [186]. Commonly available herbs cannot cure or prevent cancer Although some studies suggest that alternative or complementary therapies, including some herbs, might help patients cope with the side effects of cancer treatment, no herbal products have been shown to be effective for treating cancer.