NEW ORLEANS, La., Aug. 22 -- Large doses of vitamin C can prevent illness by alleviating the body's normal response to stress, according to a scientist at the University of Alabama in Huntsville. This study was described here today at a national meeting of the American Chemical Society, the world's largest scientific society.
The study tested the effects of vitamin C on the adrenal function of laboratory animals subjected to stress, said P. Samuel Campbell, Ph.D., chairman of the university's department of biological sciences. In both animals and humans, the adrenal gland reacts to stress by releasing corticoids, such as corticosterone and cortisol. These and other hormones trigger the "fight or flight" reaction that allows us to spring into action when in danger. They also suppress the immune system, the body's first line of defense against disease.
The Alabama researchers put laboratory rats under stress by immobilizing them for one hour a day over a three-week period. To check whether vitamin C would reduce the production of stress hormones, the rats were fed 200 milligrams a day, the equivalent of several grams a day for humans. This dosage far exceeds the present recommended daily allowance (RDA) of 60 milligrams, a figure based on the amount required to prevent deficiency diseases such as scurvy. The study showed that vitamin C reduced the levels of stress hormones in the blood-and also reduced other typical indicators of physical and emotional stress, such as loss in body weight, enlargement of the adrenal glands, and reduction in the size of the thymus gland and the spleen, according to Campbell.
In addition, the vitamin C treatment elevated the levels of circulating IgG antibody, the body's principal defense against systemic infection, he said.
In the control group-rats who were not subjected to stress-vitamin C increased the production of IgG antibody to a somewhat higher level than it did in the stressed rats. This suggests that stress may create a tolerance for vitamin C. Consequently, animals-and perhaps people-who are under emotional stress may require higher doses of vitamin C to protect immune function.
Paradoxically, the vitamin C treatment may work by suppressing production and/or utilization of the vitamin C that naturally exists in the adrenal cortex of humans and animals, Campbell noted. This endogenous vitamin C appears to support the production of stress hormones, he said.
Campbell said his results help explain other evidence of the value of vitamin C in protecting immune function. For example, according to reports in the medical literature, vitamin C boosted immune function in a test group of elderly women. It also reduced the incidence of stress-related upper-respiratory infections in marathon runners.
Recommending a sharper look at the present RDA, Campbell said he believes that our prehistoric ancestors probably consumed large amounts of vitamin C in a tropical diet rich in fruits. "If so, the physiological constitution we have inherited may require doses far larger than the present RDA to keep us healthy under varying environmental conditions, including stress."
Materials provided by American Chemical Society. Note: Content may be edited for style and length.
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