Influence of nutrients and other dietary materials on cytochrome P-450 enzymes.

The cytochrome P-450 (P-450) enzymes are collectively responsible for the bulk of oxidation of xenobiotic chemicals, including drugs, pesticides, and carcinogens. This biotransformation can result in either increased or decreased toxicity, depending on the situation. The regulation of individual P-450 enzymes is a complex subject, with examples of induction and direct inhibition and stimulation. Nutrients and food additives can modify P-450 activities and consequently influence toxicity. P-450s also influence the toxicity of potentially harmful materials found in foods, as well as some vitamins and natural products. Some of the foodstuffs and conditions that influence P-450 in experimental animals and in humans are protein, carbohydrate, lipid, obesity and fasting, water- and fat-soluble vitamins, minerals, sulfides, isothiocyanates, indoles, ellagic acid, capsaicin, terpenes, flavones, butylated hydroxytoluene and hydroxyanisole, charbroiled foods, ethanol, and (monosodium) glutamate and aspartate. Consideration is given, when possible, to differences in responses between animal models and humans.