Nutrition–Immunity Connection

I. Protein: The "Building Blocks" of Immunity

Core Role

• Antibodies and immune cells (e.g., leukocytes) are made of protein.

• Adequate protein intake directly determines immune defense capacity.

• Chronic protein deficiency impairs immune cell regeneration and slows recovery from infections.

Key Food Sources

• Animal-based: Fish, eggs, dairy

• Plant-based: Legumes, soy products (e.g., tofu)

II. Vitamins: Guardians of Immune Defense

Key Finding:

• High-dose vitamin C (1g/day for 2 months) significantly increases macrophage activity.

III. Minerals: Immune System "Controllers"

Zinc

• Drives thymus development and T-cell differentiation

• Deficiency linked to increased infection recurrence

• Sources: Oysters, beef, pecans

Iron

• Supports antibody production

• Deficiency weakens resistance to infections

• Sources: Animal blood, red meat, wood ear mushrooms

Selenium

• Enhances immune surveillance through antioxidant properties

• May reduce cancer risk

• Sources: Brazil nuts, seafood

IV. Synergistic Factors

Essential Fatty Acids

• Omega-3s (from fish oil, flaxseed) modulate immune balance

• Help reduce excessive inflammation

Gut–Immune Axis

• 70% of immune cells reside in the gut

• Dietary fiber supports a healthy gut microbiome

Hydration

• Maintains mucosal moisture (e.g., in the respiratory tract)

• Helps block pathogen entry

Warning Signs of Nutrient Deficiencies

• Protein deficiency → Reduced antibody production, slow wound healing

• Vitamin A/C deficiency → Frequent respiratory or digestive infections

• Zinc/Iron deficiency → Stunted growth (children), chronic fatigue (adults)

Fundamental Principle
Immunity thrives on balanced nutrition — excessive intake may trigger autoimmune disorders.