Many vitamins and minerals have been examined for their effects on the metabolism of foreign chemicals by microsomal systems. Most studies reported have found that the effects of deficiencies of micronutrients on microsomal enzymes are not as striking as those observed for protein deficiency. Activities of toxicant metabolism enzymes are affected to some degree, particularly if the deficiency of the micronutrient is severe.
Ascorbic Acid Vitamin C deficiency reduces toxicant metabolisms in guinea pigs. Ascorbic acid deficiency affects the liver contents of cytochrome P450 isoforms which are pivotal in the activation of food carcinogens, aflatoxin B1, and heterocyclic amines.
Other physiological effects of vitamin C deficiency include poor wound healing and capillary integrity, probably related to the vitamin’s role in collagen formation; decreased immunity; skeletal muscle atrophy; and nervous disorders. In contrast, there is little information available on the effects of excess ascorbic acid on toxicant metabolism. There is considerable controversy over the efficacy of megadoses beyond the requirement or dietary reference intake (DRI) of ascorbic acid for the prevention and treatment of diseases.
Riboflavin (Vitamin B2) Because riboflavin is an essential component (prosthetic group) of NADPH–cytochrome P450 reductases, such as the cofactors FAD and FMN, a deficiency will adversely affect toxicant metabolism. Also, a lack in riboflavin can result in uncoupling of electron transport and subsequent ROS generation.
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