Immunity
Which supplements, vitamins, foods and habits affect immunity? Every claim graded by the strength of the published research.
- Reduces diarrhea and infection risk in deficiency — Zinc (Benefit, grade A: Strong)
- Helps prevent repeat urinary tract infections in women — Cranberry (Benefit, grade B: Moderate)
- Prevents urinary tract infections in older people in care homes — Cranberry (No effect, grade B: Moderate)
- Prevents urinary tract infections in pregnancy — Cranberry (No effect, grade B: Moderate)
- Early egg introduction lowers the risk of egg allergy in babies — Eggs (Benefit, grade B: Moderate)
- Lowers death risk in critically ill patients — Probiotics (No effect, grade B: Moderate)
- Reduces inflammation — Turmeric (Benefit, grade B: Moderate)
- Eases cold symptoms — Vitamin C (Benefit, grade B: Moderate)
- Prevents colds during heavy physical stress — Vitamin C (Benefit, grade B: Moderate)
- Prevents colds in the general population — Vitamin C (No effect, grade B: Moderate)
- Shortens a cold if you start it when symptoms begin — Vitamin C (No effect, grade B: Moderate)
- Shortens colds when taken every day — Vitamin C (Benefit, grade B: Moderate)
- Lowers the risk of autoimmune disease — Vitamin D (Benefit, grade B: Moderate)
- Prevents colds and respiratory infections — Vitamin D (No effect, grade B: Moderate)
- Prevents common colds — Zinc (No effect, grade B: Moderate)
- Shortens common cold duration — Zinc (Benefit, grade B: Moderate)
- Provides all the nutrients you need — Carnivore Diet (Mixed results, grade C: Limited)
- Prevents urinary tract infections after surgery and similar procedures — Cranberry (Benefit, grade C: Limited)
- Prevents urinary tract infections in children — Cranberry (Benefit, grade C: Limited)
- Reduces antibiotic use for urinary tract infections — Cranberry (Benefit, grade C: Limited)
- Helps prevent colds — Garlic (Mixed results, grade C: Limited)
- Increases activity of some immune cells — Garlic (Benefit, grade C: Limited)
- Makes colds and flu milder — Garlic (Benefit, grade C: Limited)
- Can be given to babies under one year — Honey (Harm, grade C: Limited)
- Eases acute cough in children — Honey (Benefit, grade C: Limited)
- Eases cold symptoms overall — Honey (Benefit, grade C: Limited)
- Shortens a cough in adults — Honey (No effect, grade C: Limited)
- Linked to lower asthma risk in children — Pet Ownership (Benefit, grade C: Limited)
- Prevents C. difficile diarrhoea — Probiotics (Benefit, grade C: Limited)
- Rarely causes bloodstream infection in critically ill people and children with central lines — Probiotics (Harm, grade C: Limited)
- Reduces ventilator-associated pneumonia in ICU patients (results conflict) — Probiotics (Mixed results, grade C: Limited)
- Reduces inflammation — Red Wine (Mixed results, grade C: Limited)
- Strengthens immune function — Time in Nature (Benefit, grade C: Limited)
- Yogurt eaten in pregnancy is linked to less infant eczema — Yogurt and Kefir (Benefit, grade C: Limited)