Dietary Antioxidants as Related to Vitamin E Function

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Abstract
Chicks were fed a basal diet deficient in vitamin E and biologically active selenium with supplements of synthetic anti-oxidants at varying levels. The efficiency of the antioxidants in preventing exudative diathesis correlated with their apparent concentration in the tissues as determined by an in vitro lipid peroxidation test (thiobarbituric acid). Ethoxyquin and DPPD were most active, butylated hydroxytoluene (BHT) and ditertiary-butyl-4-methylphenol (DBPC) were intermediate, whereas nordihydroguaiaretic acid (NDGA) and 2,5-di-tertiary-amylhydroquinone (DAH) were inactive as tissue antioxidants. The presence of the antioxidants in liver and their effect on lipid peroxidation was confirmed by parallel studies of the iron-catalyzed oxidation of the isolated liver lipid. Inhibition of in vitro lipid peroxidation by dietary selenium was considerably greater than that from dietary tellurium or arsenic. These latter elements did not prevent exudates. A direct correlation between the α-tocopherol content of liver and the degree of in vitro lipid peroxidation was found. Experiments are reported which show that the slight lipid peroxidation detected in “zero time” homogenates is formed during the homogenizing procedure. The results indicate that the variation among antioxidants in their ability to substitute for vitamin E is due primarily to differences in their availability to the body and subsequent deposition in the tissues.