How it works
Multivitamins provide a range of vitamins and minerals, usually at or near recommended daily amounts. Micronutrients support energy metabolism, red blood cell formation, immune function and bone health. If your diet lacks variety, is low in calories (for example during weight loss or in weight-class sports), excludes food groups, or you are travelling, a multivitamin may help prevent shortfalls. They do not provide energy and cannot compensate for a poor overall diet.
What research supports
- Helps prevent micronutrient shortfalls in people on restricted or low-energy diets
- Useful for some vegans and vegetarians (for example vitamin B12), older adults and during travel
- Large trials show no clear performance benefit and mixed results for chronic disease prevention in well-nourished adults
Dosage
A basic multivitamin providing roughly 100% of daily values for most nutrients, taken once per day, is typical. Avoid mega-dose products and stacking several supplements that contain the same nutrients.
Timing
Take with a meal to improve absorption of fat-soluble vitamins and reduce stomach upset. Time of day does not matter much.
Side effects
- Mild stomach upset or bright yellow urine (from riboflavin)
- Risk of excess intake if combined with other supplements and fortified foods
Cautions
- Smokers and former smokers should avoid high-dose beta-carotene
- People taking blood thinners should be cautious with vitamin K-containing products
- Iron-containing products are dangerous to young children; store safely
- Pregnant people need prenatal formulations with appropriate folate and limited vitamin A
- Athletes subject to anti-doping rules should only use products certified by an independent third-party testing program for banned substances; certification lowers, but does not eliminate, the risk of contamination.
Food sources
A varied diet of fruits, vegetables, whole grains, dairy or fortified alternatives, legumes, nuts, seeds, fish and lean meats.