Do athletes need multivitamins?
Walk into any gym changing room and you will find someone swallowing a handful of vitamin tablets in the name of performance. Our editorial team looked at whether active people actually need a multivitamin, who might benefit and where routine use is simply expensive urine.
The myth: hard training means you need extra vitamins
It sounds logical. Athletes burn more energy, sweat more and put their bodies under stress, so surely they need a daily multivitamin as insurance. Supplement marketing reinforces the idea with sport-specific formulas, sachets and "performance packs".
The reality is more nuanced. Training does raise requirements for some micronutrients modestly, particularly those involved in energy metabolism such as the B vitamins. But athletes also eat more food, and a varied diet that meets higher energy needs usually delivers proportionally more vitamins and minerals at the same time.
The joint position statement on nutrition and athletic performance from the American College of Sports Medicine, Academy of Nutrition and Dietetics and Dietitians of Canada, written by Thomas, Erdman and Burke, concludes that athletes who consume adequate energy from a variety of foods generally do not need vitamin and mineral supplements.
That "if" is important. The cases where supplementation makes sense are well defined, and they are identified through diet assessment and, where appropriate, blood tests rather than by default.
What the evidence says about performance
Older controlled studies set the tone. Telford and colleagues supplemented Australian athletes with a broad vitamin and mineral product for seven to eight months and found no improvement in performance measures compared with placebo in those with adequate diets.
Large trials in the general population looking at long-term health outcomes have produced mixed results. The Physicians' Health Study II, reported by Gaziano and colleagues, found a small reduction in total cancer in men taking a daily multivitamin over more than a decade, but no clear effect on cardiovascular events. Those findings concern middle-aged and older men, not young athletes chasing performance.
The pattern across nutrition science is consistent. Correcting a genuine deficiency improves health and performance; adding more of a nutrient to someone who already has enough rarely helps and, for some nutrients, can harm.
A review by Rawson, Miles and Larson-Meyer on supplements for athlete health similarly emphasised targeted use, focusing on nutrients such as vitamin D and iron where deficiency is common and consequences are measurable.
Who may genuinely benefit
Certain groups of athletes do have a higher risk of falling short. Recognising them is more useful than a blanket recommendation.
- Athletes restricting energy: those in weight-class sports, aesthetic sports or long fat-loss phases, where total food intake is low.
- Vegans and some vegetarians: vitamin B12 is essential, and iodine, iron, zinc, calcium and omega-3 fats need attention.
- Women with heavy periods: higher iron losses increase the risk of deficiency.
- People with limited sun exposure: relevant to almost everyone in the UK during autumn and winter.
- Those planning pregnancy: folic acid is recommended before conception and in early pregnancy.
Low energy availability deserves special mention. The IOC consensus on relative energy deficiency in sport, led by Mountjoy and colleagues, describes how chronic under-fuelling affects hormones, bone and immunity. A multivitamin may plug some gaps, but it does not fix the underlying problem, which is not eating enough.
For these groups, a single targeted supplement, such as B12 for a vegan or vitamin D in winter, is often more appropriate than a broad multivitamin, and blood tests may be needed to decide.
UK recommendations worth knowing
Public health advice in the UK is unusually clear on a few nutrients. The NHS advises that everyone should consider a daily vitamin D supplement of 10 micrograms during autumn and winter, and that people who spend little time outdoors or cover most of their skin may need it all year round.
| Nutrient | Who should consider it | Comment |
|---|---|---|
| Vitamin D | Most adults in autumn and winter | 10 µg per day is the general UK advice |
| Vitamin B12 | Vegans | Fortified foods or a supplement are needed |
| Folic acid | Women trying to conceive | 400 µg daily until 12 weeks of pregnancy |
| Iron | Only if tests show deficiency | Excess iron can be harmful |
| Iodine | Vegans and those avoiding dairy and fish | Avoid seaweed supplements with variable content |
Iron illustrates why "more is better" is a dangerous assumption. Taking iron without a confirmed need can cause digestive upset and, in people with haemochromatosis, a relatively common inherited condition in people of northern European descent, contributes to iron overload.
The same applies to fat-soluble vitamins A and E, which can accumulate. Combining several products, for example a multivitamin, a "skin" supplement and fortified sports foods, is the most common way people unknowingly exceed safe upper levels.
If you choose to take one
A standard multivitamin at doses close to dietary reference values is unlikely to cause harm in healthy adults and may be a reasonable choice for someone with an erratic diet. The aim should be to fill gaps, not to megadose.
Look for a product that provides around 100% of reference nutrient intakes rather than many times that amount. Avoid formulas with high doses of vitamin A if you are pregnant or planning pregnancy, and be cautious with products that also contain stimulants, herbal extracts or "proprietary blends".
Athletes subject to anti-doping rules should use batch-tested products. Multivitamins are a low-risk category, but cross-contamination in manufacturing facilities is documented, and strict liability means the athlete bears the consequences.
Finally, treat a multivitamin as a backup, not a foundation. An analysis of emergency department visits in the United States by Geller and colleagues showed that supplements are not risk-free, even if most problems involved weight-loss and energy products rather than vitamins.
Editorial conclusions
Most athletes who eat enough food from a varied diet do not need a multivitamin to perform well. Evidence that routine supplementation improves performance in well-nourished people is lacking.
Targeted supplements, notably vitamin D in the UK winter, B12 for vegans and iron when tests confirm deficiency, are far more justified than blanket use.
If you do take a multivitamin, choose modest doses, avoid stacking products and use batch-tested brands if you compete.
Related reading on our site includes vitamin D for athletes, iron and ferritin testing, and recognising low energy availability.
References
- Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine joint position statement. Nutrition and athletic performance. Med Sci Sports Exerc. 2016;48(3):543–568.
- Telford RD, Catchpole EA, Deakin V, et al. The effect of 7 to 8 months of vitamin/mineral supplementation on athletic performance. Int J Sport Nutr. 1992;2(2):135–153.
- Gaziano JM, Sesso HD, Christen WG, et al. Multivitamins in the prevention of cancer in men: the Physicians' Health Study II randomized controlled trial. JAMA. 2012;308(18):1871–1880.
- Rawson ES, Miles MP, Larson-Meyer DE. Dietary supplements for health, adaptation, and recovery in athletes. Int J Sport Nutr Exerc Metab. 2018;28(2):188–199.
- Mountjoy M, Sundgot-Borgen JK, Burke LM, et al. IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. Br J Sports Med. 2018;52(11):687–697.
- Geller AI, Shehab N, Weidle NJ, et al. Emergency department visits for adverse events related to dietary supplements. N Engl J Med. 2015;373(16):1531–1540.
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