A high dietary intake of vitamin C may help reduce the effects of chronic stress by inhibiting the release of stress hormones, thus preventing these hormones from dampening the immune response. Previous studies have shown that stress can impair the body's immune response, increasing the risk of infectious illness. To determine if vitamin C supplementation might counter the damaging effects of stress, the authors fed mice either 100 mg or 200 mg of vitamin C daily for 3 weeks -- a dosage equivalent to several grams per day in humans. At the same time, they subjected the rats to emotional stress by restraining them from all movement for a period of 1 hour each day.
As expected, blood samples from the rats showed increased levels of antibodies associated with stress. However, rats fed 200 mg of vitamin C displayed lower-than-expected blood levels of the stress hormone cortisol -- indicating that some type of immune suppression had taken place. The findings have important implications for the prevention of stress-related illness in athletes and anyone under high amounts of physical stress. Someone who is under a lot of emotional stress may also benefit from increased vitamin C consumption. The findings also suggest that current guidelines on recommended vitamin C intake may be too low. The researchers note that the US recommended daily allowance (RDA) for vitamin C is currently set at 60 mg per day.
American Chemical Society August 23, 1999 New Orleans, LA
COMMENT: Vitamin C is one of the least expensive and safest supplements. It appears that adding doses during episodes of stress may help in limiting the significant damage that elevated cortisol levels can induce.