Effect of vitamin A on longevity

Increasing the dietary content of Vitamin A from inadequate to adequate during the developmental stages of Drosophila increased the median life span by as much as 17.5%. The optimum dietary range of concentrations of Vitamin A for increasing the life span of Drosophila was found to be between 4 and 8 IU/g food. The maximum life span was reduced as dietary concentrations of Vitamin A exceeded this value. Vitamin A palmitate and retinal inhibited the peroxidation of linolenic acid induced by the generation of superoxide radicals from acetaldehyde. Other forms of Vitamin A, such as retinol and retinoic acid, moderately inhibited lipid peroxidation at low concentrations but stimulated peroxidation considerably when present at high concentrations. Based upon the ability of these retinoids to inhibit the reduction of cytochrome c by superoxide radicals, we propose that retinoids can inhibit and stimulate lipid peroxidation depending upon their concentration by reacting with superoxide radicals. We suggest that this reaction is the basis for the apparent ability of Vitamin A to prolong and shorten life span depending upon the dietary intake.