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NEW VITAMIN C STUDY DOESN'T TELL FULL STORY

AUBURN, MAY 1---Consumers shouldn't be overly concerned about the results of a British study questioning the health benefits of vitamin C.

The study, conducted by researchers at Leicester University in England, reveals vitamin C, when consumed at or above 500 milligrams a day, provides no safeguard against body tissue oxidation -- widely perceived as a major contributor to heart disease and certain forms of cancer.

At dosages of 500 milligrams, the study revealed Vitamin C suppresses and promotes oxidation, thereby canceling out its positive effects. As evidence of the negative effects of vitamin the researcher who conducted the study, points to oxidative damage caused to white blood cells among some of the 30 volunteers who took part in the study.

However, Dr. Robert Keith, an Alabama Cooperative Extension System nutritionist, is one of a number of experts who take issue with the way the results have been interpreted.

Although it's "theoretically possible" for vitamin C to produce a canceling out effect in the body, Keith points to overwhelming evidence to the contrary.

"Viewing the body as a whole, there appears to be little risk from taking vitamin C supplements at rates as high as 500 milligrams a day," Keith says. "If there really were bad things happening from the vitamin, we would have seen them by now because there are many people taking large doses of vitamin C."

One approach in the study causing Keith concern is the fact researchers concentrated only on vitamin C's effect on white blood cells without looking at the effects on the entire body.

Studies looking at whole populations show doses of vitamin C between 200 and 500 milligrams, actually seem to protect against heart disease and some types of cancer, Keith says. As further evidence, he cites an article in the American Journal of Clinical Nutrition, which reaches similar conclusions.

In the Leicester University study, 30 volunteers were given 500 milligrams of vitamin C a day for six weeks. Before, during and after the study, researchers looked for two indicators of oxidative damage in DNA from the volunteers' white blood cells.

One indicator showed more oxidative damage while the other showed less, compared to before the supplementation began.

Several researchers, in addition to Keith, believe these results fail to refute earlier claims vitamin C provides a safeguard against heart disease and certain forms of cancer.

"One study can't tell the whole story," Keith says. "Many more studies must be reviewed before a consensus can be reached on the health effects of vitamin C."