A co-twin control study of the effects of vitamin C.

In recent years, a number of benefits of prophylactic pharmacologic doses of vitamin C have been suggested. In addition to claims by Linus Pauling [1971] and others of a reduction in the morbidity due to the common cold and upper respiratory infections, other authors have subsequently suggested that serum cholesterol levels may be lowered [Spittle, 1971]. Some investigations have suggested that this effect may be observed only in hypercholesterolemic individuals and not those with normal cholesterol levels [Sokoloff et al, 1966; Ginter et al, 1970]. It has also been suggested that exogenous vitamin C might improve mental alertness as measured by IQ test performance [Kubala and Katz, 1960]. The present study was designed to test these hypotheses by means of a double-blind co-twin control study.