Nutrients Involved in Body Defenses

Student Learning Outcomes

• Summarize the functions of the immune system, including:
  • Skin, intestinal cells, white blood cells, lymphoid tissue roles.
• Describe oxidation and reduction processes and the function of antioxidants.
• Outline functions, food sources, deficiencies, and toxicities of:
  • Vitamin A and carotenoids
  • Vitamin C
  • Vitamin E
  • Selenium
  • Zinc
• Discuss functions of phytochemicals supporting body defenses.
• Explain probiotics' benefits for the immune system's maintenance and development.
• Analyze relationships between body fatness, dietary patterns, and cancer risk.

Immune System Overview

• Collection of Diverse Tissues: Skin, intestinal cells, white blood cells, lymphoid tissue work together to:
  • Prevent infection
  • Remove abnormal cells
  • Break down aged cells
• Cell Types:
  • Phagocytes: Engulf and digest microrganisms (e.g., macrophages, neutrophils).
  • Lymphocytes: Produce antibodies marking invaders for destruction.

Nutrients Involved in Immune Function

• Vitamin A:

  • Supports epithelial cells and immunity.
  • Deficiency can cause impaired vision and weakened immune response.
  • Sources: Liver, fish, dairy, orange/yellow fruits and vegetables.

• Vitamin C:

  • Important roles: Collagen synthesis, antioxidant, enhances iron absorption.
  • Deficiency leads to scurvy: bruising and poor healing.
  • Sources: Citrus fruits, peppers, strawberries.

• Vitamin E:

  • Functions as an antioxidant, protects cell membranes.
  • Deficiency is rare; populations at risk: preterm infants, smokers.
  • Sources: Nuts, seeds, vegetable oils.

• Selenium:

  • Functions in antioxidant defense and thyroid hormone activation.
  • Deficiency can cause muscle pain and increased cancer risk.
  • Sources: Brazil nuts, fish, meats.

• Zinc:

  • Supports DNA synthesis, immune function, and protein metabolism.
  • Deficiency linked to growth issues in children and impaired immune response.
  • Sources: Meat, seafood, dairy, legumes.

Antioxidant Defenses

• Mechanisms:
  • Enzyme systems (e.g., superoxide dismutase).
  • Chemical antioxidants (e.g., vitamins A, C, E).
• Oxidative Stress:
  • Imbalance between free radical production and body’s antioxidant capacity.
  • Can lead to chronic diseases.

Probiotics and Gut Health

• Probiotics: Live microorganisms (e.g., Lactobacillus) that have health benefits.
• Prebiotics: Non-digestible food ingredients that promote beneficial bacteria growth.
• Benefits:
  • Improve gut integrity
  • Prevent diarrhea and support immune health

Cancer and Nutrition

• Cancer is influenced by:
  • Genetics (5-10% inherited).
  • Environment and lifestyle (diet, obesity, smoking).
• Nutrition Recommendations:
  • Maintain healthy weight
  • Increase consumption of whole foods (fruits, vegetables).
  • Limit red and processed meat, sugars, and high-fat foods.

Conclusion

• Total balance of nutrition is critical for promoting optimal immune function and reducing disease risks.
• Focus on diverse sources of nutrients through a balanced diet of whole foods.