Serum vitamin E and lipid peroxides in malnutrition, hyper and hypothyroidism

Serum lipoperoxides were measured, by a modified thiobarbituric acid method, in 25 children affected with malnutrition, 40 adults having hyperthyroidism and 40 adults having hypothyroidism and compared with the serum lipoperoxides content of 40 normal adults. The lipid peroxide content was 3.9 nmol/ml in normals, 1.8 nmol/ml in malnutrition, 2.5 nmol/ml in hyperthyroidism and 3.1 nmol/ml in hypothyroidism. The vitamin E content of the serum in all the cases was found to vary in the same way as the amount of circulating lipid peroxides. The serum inhibitory capacity against in vitro lipid peroxidation, using rat brain homogenate as a model system, was totally abolished in malnutrition and was decreased to about 50% in hyperthyroidism and to about 33% in hypothyroidism, as compared to normal human serum. It is concluded that the level of circulating lipid peroxides in serum is related to the serum vitamin E concentration.