The role of nutrients in cancer development Exercise There is now solid evidence that physical exercise not only prevents colorectal cancer, but also improves the prognosis after chemotherapy for many diseases. Exercise may also prevent breast, lung and precancerous cancers. Exercise requires an amount of 18-27 metabolic equivalents per week. One hour of jogging, biking, tennis, and swimming is good for 7 MET. One hour of mowing the lawn, aerobic exercise can achieve 6 MET. One hour of walking per day, 6 days a week can achieve 18 MET. The causal relationship between energy balance and cancer risk is not clearly established, but exercise reduces circulating insulin growth factor. Prospective studies have shown that high levels of IGF-1 are associated with increased incidence of breast and anterior case adenocarcinoma and may also be associated with colon and lung carcinogenesis. Exercise also improves insulin sensitivity, and type 2 diabetes is associated with increased incidence of endometrial, colon, kidney, pancreatic, and postmenopausal breast cancers. Obesity There is conclusive evidence that obesity increases the risk of endometrial cancer. The body mass index requirement is to maintain a body mass index between 18.5 and 25. A petite, desk-bound woman needs only 1450kcal a day to be adequate. Weight change in adulthood should be limited to 5kg. When BMI exceeds 28, postmenopausal women have an increased risk of breast cancer and may likewise have an increased incidence of kidney cancer. Nutrition There is conclusive evidence that vegetables and fruits can prevent cancers of the mouth, esophagus, lungs, stomach, and vegetables can also prevent colon cancer. Vegetables and fruits may likewise have a preventive effect on the occurrence of laryngeal, pancreatic, breast, and bladder cancers. Vegetables and fruits are a source of fiber, vitamins, and phytochemicals. The recommended daily consumption of vegetables and fruits per adult is 400-800g of vegetables and two fruits. Cancer formation is a process involving repeated, cumulative mutations in genes that control tissue growth; therefore, each person should consume many vegetables and fruits throughout the year. Consume vegetables and fruits when they are naturally ripe, as they are cheap and contain the richest trace elements and phytochemicals. Fruits that are the richest in natural antioxidants are those with small red fruits such as blueberries, capers, blackberries, cranberries and strawberries. Other natural antioxidants include vitamins C, E and A, coenzyme Q10, lycopene, melatonin, quercetin, selenium and zinc. Vegetables such as chicory, celery, lettuce, fennel, spinach, amaranth, and radish contain a lot of nitrates, especially after being stored for more than 2 days. When heated, they combine with proteins to form nitrosamines, which are potentially carcinogenic. 45%-60% of total energy needs should be supplied by protein-rich plants and should not be purified because of the need for vitamins, minerals and fiber inside. Polysaccharides are found in grains, legumes and starches, as well as in vegetables and fruits. The intake of purified monosaccharides and disaccharides can cause a rapid rise in blood sugar and then a rapid fall, causing a quick hunger and then an excess of energy. They are also deficient in micronutrients. Diet rich in purified sugar may increase the risk of colon cancer and rectal cancer. Diets containing adequate amounts of crude fiber may reduce the incidence of breast, colon, rectal and pancreatic cancers: 600-800g/day is recommended. Diets containing red meat may increase the risk of colorectal cancer and may also increase the risk of breast, pancreatic, kidney, and precancerous cases. Therefore, intake of beef, lamb, pork and meat products should be limited. Grilled, fried and pan-fried meat can produce heterocyclic amines, which can increase the incidence of colorectal cancer. Optional sources of vegetable protein include dry beans, soybeans, wheat bark, nuts, and seeds. A diet rich in fat may increase the risk of lung, colon, rectal, breast, and precancerous cases. Because it can easily cause obesity, it increases the occurrence of endometrial cancer, and may also increase the occurrence of kidney cancer, and postmenopausal breast cancer. Saturated fat intake should be avoided. Saturated fatty acids are mainly derived from animals, but also from cocoa butter and palm oil. Polyunsaturated fatty acids derived from linolenic acid and linoleic acid are good choices. The diet in today’s society contains unwanted large amounts of n-6 fatty acids. natural sources of N-3 fatty acids are mainly fatty fish, walnuts, flax oil and nut oils. Food Processing Low temperature steaming, boiling, simmering, stewing and braising are the preferred methods of food processing. Highly grilled or baked meats and fish may increase the incidence of stomach cancer. Grilled and fried meat is as likely to increase colorectal cancer as processed meat. Animal studies have confirmed that grilled and fried foods can produce carcinogenic heterocyclic aromatic amines, which are similar in their carcinogenic effects to nitrosamines produced by nitrous acid treatment of food. Animal studies have also shown that smoked foods produce polycyclic aromatic hydrocarbons that also show carcinogenicity. Thiamine and vitamin C are sensitive to heat. Vitamin C protects vitamins A and E, and vitamin B complex, and enhances the absorption of iron and folic acid. Balanced consumption of some raw or lightly processed vegetables is optional. Food storage To protect micronutrients, vegetables need to be stored in a dark, light-proof, cool environment. Also, the time between harvesting and consumption of vegetables should be kept as short as possible so that nitrate production is minimized. Methods of preserving food with salt should be limited. A diet rich in cured meats can increase the incidence of stomach cancer, and refrigerator storage of food not only reduces the incidence of stomach cancer, but also keeps food longer and better. Food stored in the surrounding environment can cause the growth of toxic fungi, for example, aflatoxin growth can increase the risk of liver cancer. There is no evidence that additives in food are harmful. Further research is needed. Nutritional recommendations for cancer prevention 1. Maintain physical activity and exercise: 18-27 MET per week. 2. Maintain body weight: BMI between 18.5-25, with fluctuations of less than 5 kg. 3. Eat 400-800g of raw or lightly processed vegetables and two fruits per day. Eat valuable, fresh vegetables and fruits. 4.Eat 600-800g of minimally processed grains, legumes, nuts, seeds, roots, tubers and plantain every day. 5.Avoid the use of refined sugar. 6.Avoid the use of red meat. 7.Limit fat function below 15%. Consume polyunsaturated fatty acids and maintain a balance between n-3 and n-6 fatty acids. 8.Apply herbs and spices instead of salt.