Chapter 11. Micronutrients as Antioxidants
Chapter Review
IMPORTANT: Key Takeaways
- Antioxidants are compounds that interact with and neutralize free radicals to prevent cell damage caused by oxidation.
- Oxidation is a chemical reaction wherein atoms lose electrons and when the electrons remain unpaired, they become highly reactive molecules called free radicals.
- Antioxidants work by donating an electron to a free radical and stabilize the unpaired electron, thus reducing cell damage.
- The “big three” vitamin antioxidants are vitamins A, C, and E.
- Vitamin E plays a vital role in protecting cell membranes against lipid destruction caused by free radicals and is found in many foods, especially those that are higher in fat, such as oils and nuts.
- Vitamin C protects lipids by disabling free radicals while promoting the regeneration of vitamin E. Vitamin C’s ability to easily donate electrons further increases its effectiveness as an antioxidant. Vitamin C is found in citrus fruits and many vegetables.
- Vitamin A protects cell membranes, maintains glutathione levels, and regulates enzyme activity in detoxifying free radicals. Foods such as beef liver, chicken liver, and milk are great sources of Vitamin A.
- Some research studies have shown that the “big three” antioxidants may also play an important role in reducing the risk of cardiovascular diseases, cancer, eye conditions, and dementia.
Practice Questions
- What are free radicals? How do antioxidants reduce the potential damage caused by excessive free radicals?
- What are the functions of vitamin E?
- How do vitamin E deficiencies contribute to feelings of weakness and fatigue?
- How can you maximize your vitamin C intake from foods?
- What is the most definitive sign of a vitamin A deficiency? Why?
- What are some of the signs and symptoms of selenium toxicity? How can this be prevented?
- What role do antioxidants play in cancer prevention?
- What role, if any, does vitamin E play in atherosclerosis prevention?
- What is the primary difference between dry and wet forms of age-related macular degeneration?
- Does taking vitamin C prevent colds?
