Food Toxicology 2(2+0)

Lesson 8 : Factors That Influence Toxicity

Minerals

1. Iron
   Heme synthesis is dependent on iron, and heme is essential for cytochrome P450 and mixed-function oxidase activity. Iron deficiency results in anemia but has minimal effects on cytochrome P450. Iron excesses result in enhanced production of ROS, lipid peroxidation, and oxidative stress, which destroy cytochrome P450 and mixed-function oxidase activity. Dietary supplementation of iron has been shown to promote colorectal cancer in rodents.

2. Selenium
   Several enzymes (e.g., glutathione peroxidase) require selenium as an essential component. These enzymes have key roles in protecting biological membranes from lipid peroxidation and damage by ROS. Selenium deficiencies result in more lipid peroxidation, destabilization of the microsomal membrane, and decrease in heme synthesis and increase in heme catabolism, resulting in loss of cytochrome P450 and subsequent drug metabolism.

3. Zinc
   Deficiencies of zinc seem to promote lipid peroxidation and thus decrease cytochrome P450 and mixed-function oxidase activity.