This chapter will describe what antioxidants are and then discuss the three major antioxidant micronutrients: vitamin E, vitamin C and selenium.
- 9.1: Antioxidants
- In this section, we are going to cover vitamin E, vitamin C, and selenium in detail because being an antioxidant is their primary function. Iron, copper, zinc, and manganese are cofactors for the antioxidant enzymes catalase and superoxide dismutase.
- 9.2: Vitamin E
- There are 8 different forms of vitamin E: 4 tocopherols and 4 tocotrienols. The difference between tocopherols and tocotrienols is that the former have a saturated tail, while the latter have an unsaturated tail. Within tocopherols and tocotrienols, the difference between the different forms is the position of the methyl groups on the ring. The 4 different forms within the tocopherol and tocotrienols are designated by the Greek letters: alpha, beta, gamma, and delta.
- 9.3: Vitamin C
- Vitamin C is well-known for being a water-soluble antioxidant. Humans are one of the few mammals that don't synthesize vitamin C, making it an essential micronutrient. Other mammals that don't synthesize vitamin C include primates, guinea pigs, and other less prevalent species. Vitamin C's scientific names are ascorbic acid or ascorbate and the oxidized form is dehydroascorbic acid or dehydroascorbate.
- 9.4: Selenium
- Selenium can be divided into two categories: organic and inorganic. The organic forms contain carbon, while the inorganic forms do not. The primary inorganic forms of selenium are selenite and selenate. Selenite and selenate are not commonly found alone in nature; they are usually complexed with sodium to form sodium selenite and sodium selenate.
Thumbnail: Citrus fruits were one of the first sources of vitamin C available to ships' surgeons. Image used with permission (Public Domain; Agricultural Research Service).