How do I boost my immune system?

There's no shortcut. Adequate sleep, regular moderate exercise, a varied diet rich in vegetables and protein, not smoking, moderate alcohol, stress management, and staying current on vaccines. Most "immune-boosting" supplements show little benefit unless you're deficient.

Deficiency correction is the one place supplements clearly help. If vitamin D, zinc or B12 is genuinely low on testing, correcting it improves immune function; taking extra when levels are normal does not.

Chronic conditions matter more than supplements. Poorly controlled diabetes, untreated sleep apnoea and smoking impair immune defence far more than any diet gap.