Nutrition Basics: An Active Approach v3.0

Chapter 8: Nutrients Important as Antioxidants

Section 8.1: Generation of Free Radicals in the Body

• Learning Objectives:

  • Describe how free radicals are generated in the body.

  • Explain oxidative stress and diseases associated with it.

Free Radical Basics

• Atoms: Basic building blocks of matter (living and nonliving)

  • Composed of neutrons, protons, and electrons.

• Stability: Atoms are stable when electrons are paired; unpaired electrons result in free radicals.

• Free Radicals: Highly reactive molecules with unpaired electrons (e.g., superoxide).

• Reactive Oxygen Species (ROS): Oxygen-containing molecules with unpaired electrons.

Body's Defense Against Free Radicals

• Antioxidants: Molecules that prevent free radicals from stealing electrons.

• Enzyme Systems:

  • Superoxide Dismutases (SOD)

  • Catalase

  • Glutathione Peroxidases

• Types of Antioxidants:

  • Hydrophilic (water-soluble)

  • Hydrophobic (lipid-soluble)

• Endogenous Antioxidants: Glutathione and uric acid.

• Dietary Antioxidants:

  • Vitamins: A, C, E

  • Selenium

Antioxidants from Diet and Their Functions

• Vitamin A:

  • Protects cellular membranes, reduces inflammation.

• Vitamin E: Protects membranes and prevents glutathione depletion.

• Vitamin C: Protects nucleic acids and regenerates vitamin E.

• Carotenoids: Scavenge free radicals.

• Lipoic Acid: Aids in vitamin regeneration.

• Selenium: Maintains glutathione levels.

Oxidative Stress & Disease

• Oxidative Stress: Imbalance between free radicals and antioxidants leading to cellular damage.

• Associated Diseases:

  • Cancer, Atherosclerosis, Arthritis

  • Diabetes, Kidney disease, Neurological disorders (Alzheimer’s, Schizophrenia)

  • Cataracts, Emphysema, Aging

Section 8.2: Antioxidant Micronutrients

• Learning Objectives:

  • List antioxidant nutrients and food sources.

  • Explain health benefits of phytochemicals.

Antioxidant Vitamins

• Vitamin E:

  • Eight forms; vital for immune function and maintaining blood vessels.

• Vitamin C:

  • Water-soluble; effective antioxidant, found in citrus and vegetables.

• Vitamin A:

  • Three forms (retinol, retinal, retinoic acid); essential for vision and immune health.

Phytochemicals

• Non-nutrient plant chemicals that affect health.

• Functions:

  • Mimic hormones, alter cholesterol absorption, inhibit inflammation.

• Carotenoids:

  • Linked to decreased risks of AMD and cancers.

• Flavonoids:

  • Lower risk of cardiovascular diseases.

• Organosulfur Compounds:

  • Found in garlic and onions; reduce cancer risk.

Antioxidant Minerals

• Selenium: Essential for detoxifying free radicals and supporting immune health.

• Manganese, Iron, Copper, Zinc: Important for detoxification; excessive amounts can be harmful.

Section 8.3: The Whole Nutrient Package versus Disease

• Health Benefits of Variety in Food:

  • A diverse diet is key to accessing a range of nutrients and phytochemicals.

  • Cannot replace a healthy diet with a single supplement.

• Strategies to Improve Intake:

  • Support local sources of fruits/vegetables, promote community gardens, and encourage healthier food policies.

• Key Takeaways:

  • Focus on a diet rich in fruits and vegetables to mitigate chronic diseases.

  • Many Americans do not meet recommended intake levels; various initiatives can foster improvement.

Key Terms

• Antioxidants: Molecules that prevent free radicals from stealing electrons.

• Free Radicals: Highly reactive molecules with unpaired electrons that can cause cellular damage.

• Oxidative Stress: Imbalance between free radicals and antioxidants leading to cellular damage.

• Reactive Oxygen Species (ROS): Oxygen-containing molecules with unpaired electrons that can contribute to oxidative stress.

• Phytochemicals: Non-nutrient plant chemicals that affect health, often functioning as antioxidants.

• Carotenoids: A class of phytochemicals linked to decreased risks of age-related macular degeneration and cancers.

• Selenium: A mineral that plays a crucial role in detoxifying free radicals and supporting immune health.

• Vitamin A: A fat-soluble vitamin essential for vision and immune health, has three forms (retinol, retinal, retinoic acid).

• Vitamin C: A water-soluble vitamin that acts as an effective antioxidant and is found in citrus and vegetables.

• Vitamin E: A vitamin important for immune function and blood vessel maintenance; contains eight forms.

- A diverse diet rich in fruits and vegetables is essential for providing a range of nutrients and phytochemicals that help mitigate chronic diseases. - Antioxidants play a critical role in protecting cells from damage caused by free radicals and oxidative stress. - Various vitamins (A, C, E) and minerals (like selenium) are vital in supporting the body’s antioxidant defenses. - Phytochemicals found in plants can lower the risk of certain diseases, including cancer and cardiovascular conditions. - Meeting recommended intake levels for these nutrients is crucial, as many people do not achieve them through diet alone.