Multivitamin for Immune Function
Multivitamins help immune function when they correct a deficiency; in replete adults they do not reduce infection rates.
Overview
Verdict
How It Works
Dosing & Protocol
Typical dose
- Recommended dose
- One standard daily multivitamin at around 100% of reference intakes, taken with food
- Expected timeframe
- Weeks to months if correcting a deficiency
Protocol
- form
- A standard once-daily multivitamin including vitamins A, C, D, E, B6, B12, folate, zinc, selenium, iron and copper
- duration
- Ongoing where intake is inadequate
- co factor
- Take with a meal. Evidence is mixed. The mechanistic case is solid - vitamins A, C, D, E, B6, B12, folate, zinc, iron, copper and selenium all have defined roles in innate and adaptive immunity, and deficiency in any of them measurably impairs immune function, which is well documented. Trials in older adults and in undernourished populations show multivitamin or specific micronutrient supplementation can improve immune markers and, in some studies, reduce infection duration. But in well-nourished adults, randomised trials generally show no reduction in the incidence or severity of respiratory infections, and Cochrane reviews of individual nutrients such as vitamin C find at most a small reduction in cold duration with regular use, not prevention.
- titration
- No titration; do not exceed the labelled dose or stack overlapping products
- starting dose
- One tablet daily with food
Evidence
What the studies say
Effect of multivitamin and mineral supplementation on immune function in the elderly: a randomized trial
Avenell A, Campbell MK, Cook JA +8 more
Multivitamin and mineral supplementation did not reduce infection rates, days of infection or primary care contacts compared with placebo
Effect of a multivitamin and multimineral supplement on infection and quality of life: a randomized, double-blind, placebo-controlled trial
Barringer TA, Kirk JK, Santaniello AC
Reported infection-related illness was lower with a multivitamin, driven mainly by participants with type 2 diabetes.
Safety
Caveats
Immune support claims are among the most oversold in the supplement market, and no product prevents infection. The measures with real evidence are vaccination, hand hygiene, adequate sleep, not smoking, managing chronic conditions and correcting genuine deficiencies - vitamin D deficiency in particular is common in winter at higher latitudes and worth testing or supplementing at standard doses. Recurrent, severe or unusual infections need medical assessment for underlying immunodeficiency, diabetes or haematological disease rather than supplementation. Safety ceilings: vitamin A retinol above 3,000 mcg/day is teratogenic and raises fracture risk; vitamin D above 100 mcg (4,000 IU)/day; vitamin B6 above 100 mg/day causes peripheral neuropathy; zinc above 40 mg/day causes copper deficiency and can itself impair immunity; selenium above 400 mcg/day is toxic; iron above 45 mg/day is toxic and should not be taken during acute infection without advice, since iron availability can favour bacterial growth. Beta-carotene increased lung cancer risk in smokers in the ATBC and CARET trials. Avoid stacking multiple immune products, which frequently duplicate zinc and vitamin C. Use a pregnancy-specific formulation in pregnancy, which excludes retinol.
Less likely to help if
Medical Disclaimer
The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.
Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.