Vitamin C the scorbutic diet was fed. Men in both studies on a diet devoid, or nearly devoid, of vitamin C had blood levels of vitamin C too low to be accurately measured when they developed signs of scurvy and, in the Iowa study, at this time were estimated (by labeled vitamin C dilution) to have a body pool of less than 300 mg, with daily turnover of only 2.5 mg/day, implying an instantaneous half-life of 83 days by this time (elimination constant of 4 months). Vitamin C has a definitive role in treating scurvy, which is a disease caused by vitamin
Vitamin A deficiency and lymphocytes. Suppression of these result in a lack of immune reaction if pathogens become present in the body and consequently a greater susceptibility to incubation of disease. VAD and infections aggravate each other, so with infection, vitamin A levels are depleted, which in turn reduces intestinal absorption of vitamin A. Very often seen with VAD is protein energy malnutrition, in which the synthesis of retinol binding protein (RBP) is decreased, consequently the uptake of retinol is reduced. This leads to an inability to use any vitamin A present as the RBP is absent, so the retinol cannot be transported