Excessive Fat
The average American diet contains about 34.1 percent of calories from fat. Animal experiments and human epidemiologic studies have revealed that this level of fat consumption may increase the risk of certain types of cancer, particularly breast, colon, prostate, and possibly other cancers. Conversely, reducing fat intake lessens the risk of these cancers. High levels of fat, therefore, act as a tum or promoter. There is no exact explanation for the effects of a high-fat diet on increasing cancer risk, but some laboratory studies have reported that the production of prostaglandin E2 (PGE2), a chemical that is produced by lipids in the body, is greatly increased in animals that are fed a high-fat diet. High levels of PGE2 have been shown to impair the body’s’ immune system. Therefore, the amplified cancer risk brought about by a high-fat diet may be due to the suppression of the body’s defense system against cancer. High doses of vitamin E succinate may block some of the harmful effects of excessive fat consumption by reducing the action of PGE2 on cells. This does not mean that one should continue eating a high-fat diet and take large amounts of vitamin E; a high-fat diet may still heighten the risk of heart attack. The relationship between diet- and lifestyle related agents and cancer risk is listed below:
Probable dietary- and lifestyle-related causative agents and increased risk of cancer
• Excessive fat – prostate cancer, breast cancer, stomach cancer, colon cancer, rectum cancer, pancreas cancer, kidney cancer
• Excess protein – breast cancer, endometrium cancer, prostate cancer, colon cancer, rectum cancer, pancreas cancer, kidney cancer
• Excess total calories – most cancers
• Alcohol – lung cancer, cervix cancer, larynx cancer, mouth cancer, esophagus cancer
• Excess caffeine/coffee – pancreas cancer, lung cancer, liver cancer, mouth cancer, larynx cancer, bladder cancer
• Excess saccharine – bladder cancer
• Cadmium from diet or smoking – kidney cancer
• Excess zinc – all cancers, especially breast and stomach
• Iron deficiency – stomach and esophagus cancers
• Iodine deficiency – thyroid cancer
• Excess smoked meat or fish – stomach cancer
• Charcoal-broiled meat, pickled products – stomach cancer
• Cancer-causing viruses – liver, certain blood cancers, cervix cancer
A high-fat diet can raise the levels of circulating estrogen in females, and high levels of estrogen are known to act as a tumor promoter. In addition, the presence of large amounts of bile acids and fatty acids from a diet rich in fat may promote colon cancer, because these substances encourage the proliferation of cells in the colon. Increased cell proliferation make colon cells more sensitive to cancer formation. Dietary calcium inhibits this action of bile acids and fatty acids by making them insoluble and tendering them unavailable for absorption.
