This is a more specific, stronger claim than “multivitamins are generally fine to take,” and it’s worth separating the two — see our broader multivitamin deep-dive for the fuller picture. The specific claim here — that a daily multivitamin meaningfully prevents heart disease or cancer — doesn’t hold up against the trial evidence.

The largest and longest relevant trial, the Physicians’ Health Study II ^[1], randomised over 14,000 male physicians aged 50 and older to a daily multivitamin or placebo for more than a decade. It found a statistically significant but modest reduction in total cancer incidence — but no reduction in cardiovascular disease, and no reduction in cancer or cardiovascular mortality. That’s a real, specific finding in a specific population, not the broad “prevents heart disease and cancer” claim as usually stated.

The US Preventive Services Task Force’s 2022 recommendation statement ^[2] reviewed this trial alongside the wider body of evidence and concluded the current evidence is insufficient to recommend multivitamin supplementation for cardiovascular disease or cancer prevention in the general adult population. That’s the key phrase worth sitting with: “insufficient evidence” isn’t the same as “definitively doesn’t work,” but it’s also nowhere close to “prevents heart disease and cancer,” the version of the claim that gets repeated in marketing.

One large trial found a narrow, specific benefit. The claim in circulation is much broader than that finding supports.

This is supplement-adjacent content, so the standard note applies with extra weight: nothing here is a recommendation to take or avoid a specific product, and none of it is a therapeutic claim.