Vitamin C prophylaxis in a boarding school.

A double-blind study to evaluate vitamin C supplements for respiratory-infection prophylaxis was conducted among 641 children at a Navajo boarding school over a 14-week period. Supplements of 1 and 2 g, or placebo, were given daily. A sample of each group had serial blood ascorbic acid determinations, which showed significant rises among groups treated with vitamin C, but no difference in mean levels between those receiving 1 and those given 2 g. Although there was no difference between treatment groups in number of respiratory episodes, those given vitamin C had fewer days of morbidity than those receiving placebo, both in older (34 per cent) and in younger (28 per cent) age groups. In active surveillance, there were 26 per cent fewer symptomatic days observed in younger vitamin C groups, and 33 per cent fewer in older girls on vitamin C. No such difference was seen in older boys. Nasal discharge and cough-were the two symptoms apparently benefited. Significantly more children on vitamin C had no sick days observed in the periodic survey. In addition, treated children with higher blood ascorbic acid levels had fewer symptomatic days noted than those with lower levels. (N Engl J Med 290:6-10, 1974) IN his book, Vitamin C and the Common Cold, Linus Pauling claimed that ascorbic acid in large daily doses could prevent upper respiratory infections. He recommended 1 to 3 g daily for prophylaxis. These speculations were based on the results of several clinical trials, as well as personal experience and evolutionary considerations. However, the studies on which Dr. Pauling relied had defects in design or reporting (or both) that rendered their results inconclusive. Since the appppearance of Dr. Pauling's book, two clinical trials have been published that show some benefit of vitamin C. Aniderson, Reid and Beaton conducted a large double-blind study with adult "cold-prone" volunteers over a two-month period. They found a highly significant (30 per cent) reduction in days of disability among the group receiving 1 g of ascorbic acid daily as compared with the placebo group. Wilson and Loh, who assessed the prophylactic value of placebo and 200 mg or 500 mg of ascorbic acid in school children over a nine-month period, found that catarrhal cold sympFrom the Fort Defiance Indian Hospital, Navajo Area. U. S. Public Health Service (address reprint requests to Dr. Coulehan at the Division of Indian Health. Fort Defiance Public Health Service Indian Hospital. P.O. Box 649. Fort Defiance. Ariz. 86504). toms were reduced by over 50 per cent in girls taking 500 mg of ascorbic acid daily, but there was no consistent effect in boys. The present investigation was designed to test the null hypothesis that daily vitamin C supplements and placebo supplements have identical effects as prophylactic agents in respiratory disease. To test this hypothesis, a double-blind study in a Navajo boarding school was conducted, daily vitamin C supplements of 1 and 2 g versus placebo being used. METHODS AND MATERIALS