A recent survey shows that 62 percent of Americans claim to use dietary supplements. More than three-quarters of all American adults are confident in their quality and effectiveness. However, studies about using supplements to prevent diseases like cancer are disappointing. In contrast, most studies about vegetables and fruits show benefits to eating these foods.
Supplements are used to reduce cancer risk or improve health in general, mostly because of their reputed antioxidant activity. Scientists tell us that antioxidants, like vitamin C, eliminate free radicals – unstable molecules the body naturally produces or other factors, like smoking, create. If left alone free radicals can harm cells, initiating a range of diseases including cancer, as well as hastening the aging process.
About half of regular supplement users take a multivitamin; a third take single antioxidant supplements like vitamins C and E and beta-carotene. Some manufacturers and even doctors encourage excessive supplement use. They argue that if a few antioxidants are good, more would be better.
Make your first choice a healthy diet
A daily multivitamin that supplies 100 percent of the Dietary Reference Intake (DRI) of vitamins and minerals is recommended for people as they mature. But large doses of a single dietary supplement can have adverse effects. For example, in two large clinical trials, people at high risk for lung cancer actually showed higher rates of lung cancer while taking beta-carotene supplements. In another large study of vitamin E supplements, doses of more than 200 International Units (IU) raised the risk of death. The recommended dietary allowance for vitamin E is about 22 IU.
Cancer patients, in particular, should be cautious about taking supplements. They should talk with their doctor first. It is possible that high doses of antioxidants may actually interfere with cancer treatment, because free radicals are created by many cancer treatments to attack cancer cells.
Even if a multivitamin can remedy a diet deficiency for some people, no supplement can replace a mostly plant-based diet, which is essential for good health. The westernization of traditional Asian diets shows why. As Koreans have begun to eat more calories and fat and fewer plant foods, for instance, their disease rates have risen. The most recent statistics for Korea show that since 1990, the death rates for colon cancer have climbed by 75 percent, for pancreatic cancer by 63 percent, for breast cancer by 37 percent, and for prostate cancer by 200 percent. A decline in the consumption of plant foods with their many antioxidant vitamins, minerals and phytochemicals, as well as other beneficial substances, may be the reason.
To find out more about supplements and the benefits of a good diet, call the American Institute for Cancer Research and request a free copy of the brochure The Facts on Supplements. The number to dial is 1-800-843-8114, ext. 111.