BUILT ON A BEDROCK OF LIES:

In natural form, they're essential to the proper functioning of our bodies. The term "vitamins" covers a diverse array of molecules that fulfill a huge variety of biochemical functions -- helping human beings to grow, repair damaged tissue, and avoid such diseases as scurvy, rickets, and pellagra. In the modern world, the abundant supply of a wide variety of foods makes it possible to satisfy virtually all nutritional needs by eating a healthful, balanced diet rich in vegetables, fruit, and protein sources. But based on the idea that more of a good thing is better, companies are now selling Americans $12 billion worth of vitamins a year. Many scientists and doctors, however, question the value of gobbling vitamins -- and there is evidence that large doses of some vitamins may actually be harmful. A recent long-term study of more than 400,000 people concluded that "most vitamin supplements [have] no clear benefit" and warned that excess vitamin E and beta-carotene may actually weaken the immune system's ability to kill cancer cells. "The case is closed," the study authors wrote. "Enough is enough."

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