Nutrition D.7

Question 1

7.1. Outline the role of antioxidants in the body

Answer 1

• Antioxidants are molecules that can prevent or limit the damaging effects of free radicals by turning the damaging effects of free radicals into substances that are far less reactive
• Free radicals are produced in the body as a by-product of normal cellular function

Question 2

What vitamins and minerals are antioxidants?

Answer 2

• Vitamins A, C and E
• Selenium, Copper and Manganese are components of enzymes also involved in defense against free radicals
• Berries, red grapes, kale, broccoli and tea are examples of foods that contain antioxidants

Question 3

7.2. Explain the harmful effects of free radicals at the cellular level

Answer 3

Free radicals in the body include:

• Superoxide
• Hydroxyl
• Nitric oxide

They can:

• Remove electrons from cell, mitochondrial membranes, and from molecules such as enzymes and DNA, thereby affecting their permeability and impairing their function

Question 4

7.3. Describe free radical production during exercise

Answer 4

• Free radicals are produced as a by-product of normal cell function, and cells produce natural antioxidants to counteract them
• Exhaustive exercise generates high levels of free radicals that cannot be controlled by natural antioxidants so that damage to cells may occur – this is known as oxidative stress
• Training partially reduces the build-up of free radicals as a result of exhaustive exercise

Question 5

7.4. Evaluate the role of antioxidants for combating the effects of free radicals

Answer 5

• Antioxidants are found in many foods, especially fruits and vegetables, and so are consumed as part of a healthy, well-balanced diet
• Many athletes consume antioxidants in dietary supplements as an extra defense against free radical damage
• There is no consistent evidence that these supplements reduce oxidative stress or have a positive impact on training or performance unless a pre-existing dietary deficiency exists
• Excess intake (above the recommended daily allowance [RDA] may have detrimental effects on the body
• A lack of adequate regulation of the supplement industry = some products are poorly formulated, may contain banned substances