New Recommendations for Vitamin C

A new study by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDKD) has determined that current guidelines for women regarding vitamin C intake are insufficient.

Not surprisingly, the original research that determined optimum daily allowance levels of vitamin C was based on studies involving only men. In recent years, researchers have finally begun to realize the biological differences between the sexes-and a wide variety of medical recommendations are in the process of being altered to reflect the differing needs of men and women.

This recent study, which appeared in the Proceedings of the National Academy of Sciences, was led by the NIDDKD's Dr. Mark Levine. He noted the earlier recommendations were not only based on the needs of men but also focused on preventing a perceived deficiency-rather than looking at what benefits vitamin C could provide.

Based on their findings, Levine's team urged that the current recommended daily allowance of 75 mg for women should be increased to 90 mg. However, he cautioned that the best way to get vitamin C is through eating five servings of fresh fruits and vegetables a day rather than with supplements.

Unfortunately, a recent Department of Agriculture study found that 43 percent of women and 39 percent of men don't get enough daily vitamin C.

While a little more vitamin C is certainly a good thing, too much can be bad for your health. Megadoses of vitamin C-and of any supplement for that matter-can have a wide range of side effects. In the case of vitamin C, nutritionists warn that more than 2,000 mg per day can skew laboratory results, cause diarrhea, and result in other side effects.

At recommended doses, however, a growing body of research is suggesting that vitamin C-one of the most popular dietary supplements-can play a role in preventing the onset of cancer and other chronic diseases. Studies have shown that healthy adults can benefit in many ways from a daily intake of up to 100 to 200 mg of vitamin C. A healthy body can absorb about 200 milligrams a day; the surplus is carried away with urine.

SOURCES:
Proceedings of the National Academy of Sciences, August 14, 2001; 98:9842-9846
Science, June 15, 2001; 292:5524
Journal of the American Medical Association, April 21, 1999; (281)15

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