Nutrition for Immune Resilience in Midlife and Beyond

Jul 17, 2025

As we age, our immune system becomes less efficient, a process known as immunosenescence. This increases susceptibility to infections, cancer, and chronic inflammation.

Nutrition plays a profound role in shaping immune resilience at every age—and especially from midlife onward.

This article explores which nutrients, foods, and habits have the strongest evidence for supporting immune function.

The Ageing Immune System

Key changes with age:

  • Reduced production of naïve T cells.
  • Impaired antibody responses.
  • Chronic low-grade inflammation (“inflamm-ageing”).
  • Altered gut microbiota composition.

These factors combine to weaken defences and increase disease risk.

Core Immune-Supporting Nutrients

✅ Vitamin D:

  • Essential for innate and adaptive immunity.
  • Deficiency linked to respiratory infections and autoimmune risk.
  • Aim for serum 25(OH)D >100 nmol/L.
  • NZ Ministry of Health recommends supplementation especially in winter.

✅ Zinc:

  • Cofactor for >300 enzymes involved in immune defence.
  • Supports T-cell maturation and antiviral response.
  • Food sources: oysters, beef, pumpkin seeds.

✅ Vitamin C:

  • Antioxidant protecting immune cells from oxidative stress.
  • Enhances neutrophil function.
  • Supplementation can shorten the duration of respiratory infections.

✅ Omega-3 Fatty Acids (EPA/DHA)

  • Resolvins help resolve inflammation.
  • May support balanced cytokine response.
  • Sources: fatty fish, algae oil supplements.

✅ Selenium

  • Supports glutathione peroxidase activity.
  • Deficiency impairs antibody response.

The Gut-Immune Axis

Over 70% of immune cells are located in the gut.

  • Dysbiosis contributes to leaky gut and inflammation.
  • Prebiotic fibres (onion, garlic, asparagus) and polyphenols support diversity.
  • Probiotics may enhance NK cell activity.

Dietary Patterns

Mediterranean Diet Benefits:

  • High in fruits, vegetables, olive oil, and fish.
  • Associated with lower CRP (C-Reactive Protein) and IL-6 – inflammation markers
  • Improves gut microbiota diversity.

Calder et al., Nutrients 2020, demonstrated the link between diet quality and immune competence.

Reduce:

  • Ultra-processed foods.
  • Alcohol
  • Added sugars.

Daily Food Strategies

  • Eat colourful vegetables daily.
  • Include oily fish 2–3 times/week.
  • Incorporate fermented foods.
  • Limit alcohol

Conclusion

Building immune resilience is a long game. With the right nutrition and lifestyle, you can strengthen your defences and age with vitality.