20.17: Cancer Prevention
Several factors can increase the risk of cancer in an individual. About 50% of cancer cases can be prevented by adopting a healthy lifestyle, regular exercise, eating healthy, and following a modest cancer prevention diet. Epidemiological studies have consistently shown that populations with vegetable and fruit-rich diets have reduced the incidence of cancer. On the other hand, populations who have a diet rich in animal fat, red meat, junk food, or high calories are predisposed to cancer.
Some naturally occurring phytochemicals such as flavonoids, carotenoids, vitamins, terpenes, sterols, indoles, and phenols have been shown to have anti-cancer properties. The flavonoids and isoflavonoids are secondary plant metabolites and are particularly important in cancer prevention. Flavonoids are found in all terrestrial vascular plants, whereas isoflavonoids are found in legumes, such as soybeans. In general, flavonoids and isoflavonoids prevent cancer development by inhibiting the cell cycle and abnormal cell proliferation, reducing oxidative stress and inducing detoxification enzymes, stimulating the immune system, and apoptosis.
Regular physical activity also helps to reduce the incidence of several types of cancer, including cancers of the colon and breast. Regular exercise increases the movement of food through the intestine, thereby reducing the length of time the bowel lining is exposed to a mutagen. Similarly, rigorous physical activity may decrease the exposure of breast tissue to circulating estrogen, thus reducing the risk of breast cancer.
Besides, daily exercise and a balanced diet can help control excessive weight gain or obesity, which is associated with an increased risk of cancer of the breast, endometrium, gallbladder, pancreas, kidney, adenocarcinoma, and esophagus.