The Alabama researchers say they "stressed" lab rats by immobilizing them for one hour a day and then fed them 200 milligrams of vitamin C, more than the recommended daily allowance for humans. They say vitamin C reduced the levels of stress hormones in the blood along with other typical indicators of physical and emotional stress, such as body weight loss, enlargement of the adrenal glands, and reduction in the size of the thymus gland and the spleen.
The study shows vitamin C elevated the levels of circulating antibodies needed to fight off infection and in rats that were given the vitamin but not under stress, that was even more evident. Researchers say that shows the body may create a tolerance for vitamin C and need higher doses to protect the immune system.
There are tests on humans that show vitamin C boosted immune function in elderly women and reduced the incidence of stress-related upper-respiratory infections in marathon runners. Researchers say the key now is to bring the data together.
