Multivitamin (General Adult)

Commonly used for
NutritionHealthy Aging
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What is it? / Overview
A multivitamin supplies RDA-level amounts of multiple vitamins and minerals to cover dietary shortfalls, particularly for restrictive diets, bariatric surgery, or older adults with reduced intake. The honest picture from large systematic reviews (including the USPSTF's 2022 review) is that in already well-nourished adults, this does not measurably reduce death, heart disease, or cancer risk -- it's a reasonable gap-filler, not a disease-prevention tool.
How is it used? / Administration
Form: Broad-spectrum multivitamin-mineral tablet or capsule, RDA-level dosing
Typical dose studied: One daily serving per label
Timing: With food -- improves absorption of fat-soluble vitamins and reduces nausea
Pooled RCTs show no all-cause mortality benefit. Avoid high-dose beta-carotene formulations if a current or former smoker (increased lung cancer risk in trials). Products with added iron carry the standard hemochromatosis caution even though most adult multis contain little or no iron -- check the label.
How well does it work? / Evidence
~ Moderate evidence
Who should avoid it?
Avoid with: Hemochromatosis / Iron overload; Tobacco use disorder / Nicotine dependence
Interacts with: Warfarin -- vitamin K content may reduce anticoagulant effect; Levothyroxine, tetracyclines, fluoroquinolones, bisphosphonates -- iron/calcium/magnesium/zinc content reduces absorption; separate dosing by several hours
Already taking it? Reasonable to continue as dietary insurance; check the product doesn't duplicate a separately-dosed nutrient (e.g. iron, vitamin D) already being taken.
Research & references
O'Connor EA et al. (2022). Vitamin and Mineral Supplements for the Primary Prevention of Cardiovascular Disease and Cancer. JAMA (USPSTF systematic review). US Preventive Services Task Force (2022). Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: USPSTF Recommendation Statement. JAMA. Jenkins DJA et al. (2018). Supplemental Vitamins and Minerals For CVD Prevention and Treatment. JACC.
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