Fez – For decades, vitamin supplements have been marketed as an easy route to better health, with shelves lined with pills promising stronger immunity, sharper minds, and longer lives. But mounting evidence suggests that for most healthy adults, food—not pills—remains the best source of essential nutrients.
Health authorities such as the US Preventive Services Task Force find no strong evidence that routine supplementation prevents heart disease or cancer in the general population.
In fact, the panel advises against beta-carotene and vitamin E for prevention, citing trials that linked high doses of beta-carotene to increased lung cancer risk in smokers, as seen in the ATBC and CARET studies.
Risks of over-supplementation
Experts stress that more is not always better. Fat-soluble vitamins like A and D can build up to toxic levels, causing symptoms from nausea to organ damage.
The NIH fact sheet on vitamin A warns of severe side effects at high intakes, while the VITAL trial found that daily vitamin D3 did not significantly reduce cancer or heart disease overall.
Another NEJM study concluded that vitamin D supplementation did not prevent fractures in midlife and older adults living in the community.
When vitamin D and omega-3s make sense
Despite limited population-wide benefits, vitamin D may be appropriate for those with low sun exposure or diagnosed deficiency.
Omega-3 supplements, according to VITAL’s cardiovascular findings, show little effect in frequent fish-eaters but may reduce heart attack risk in people who consume little or no fish.
Multivitamins and aging
Some evidence suggests multivitamins could benefit older adults.
The Physicians’ Health Study II linked daily multivitamins to a modest reduction in cancer risk among men, while the COSMOS-Mind trial found slower cognitive decline in seniors taking them.
Researchers caution, however, that these effects are small and not a substitute for a nutrient-rich diet.
Who should supplement?
Guidelines are clear for certain groups. Pregnant women are advised to take 400–800 micrograms of folic acid daily before conception through the first trimester to reduce neural tube defects, as recommended by the WHO, NHS, and USPSTF.
People with diagnosed nutrient deficiencies, those on medications like metformin that lower vitamin B12, and institutionalized seniors with limited sun exposure may also benefit from targeted supplementation.
For most, a balanced diet rich in vegetables, fruits, whole grains, nuts, dairy, and fish is the safest way to meet nutrient needs.
Supplements can play a role in specific situations, but experts emphasize sticking to doses close to the daily recommended intake and seeking medical guidance before starting any regimen.
