Benefits of Multivitamins

Evidence-Based Benefits

• Cognitive function preservation — the COSMOS-Mind trial (Baker LD et al., 2022, PMID: 35653014), a randomized, double-blind, placebo-controlled study of 2,262 older adults, found that daily multivitamin supplementation (Centrum Silver) for 3 years significantly improved global cognition, with benefits equivalent to slowing cognitive aging by approximately 2 years compared to placebo
• Modest cancer risk reduction — the Physicians' Health Study II (Sesso HD et al., 2012, PMID: 23117775), a large-scale RCT following 14,641 male physicians for a mean of 11.2 years, found daily multivitamin use reduced total cancer incidence by 8% (HR 0.92, 95% CI 0.86-0.998, p=0.04), though no significant reduction was found for individual cancer types
• Nutrient gap correction — Ward (2014, PMID: 24724766) analyzed NHANES data and found that multivitamin/mineral use significantly reduced the prevalence of inadequate intakes for vitamins A, C, D, E, calcium, and magnesium, with the largest improvements seen in vitamin D and vitamin E adequacy
• Immune support — multivitamins provide zinc, vitamin C, vitamin D, and selenium, all of which play essential roles in innate and adaptive immune responses; older adults and those with restricted diets are most likely to have suboptimal intake of these immune-critical micronutrients
• Energy metabolism — B-vitamins (B1, B2, B3, B5, B6, B12, folate) serve as cofactors in mitochondrial energy production pathways; correcting subclinical deficiencies in these vitamins can reduce fatigue, particularly in populations at risk such as older adults and those on proton pump inhibitors (Lam JR et al., 2013, PMID: 24327038)

What the Research Says

Multivitamins are the most studied supplement category, yet evidence for their benefits has historically been mixed. The tide shifted meaningfully with two landmark trials. The Physicians' Health Study II (Sesso et al., 2012), following 14,641 male physicians for over 11 years, found that daily multivitamin use modestly but significantly reduced total cancer incidence by 8%. The COSMOS-Mind trial (Baker et al., 2022), a well-designed ancillary study of the COcoa Supplement and Multivitamin Outcomes Study, demonstrated that daily multivitamin supplementation significantly improved global cognition in 2,262 older adults over 3 years, with benefits equivalent to approximately 2 years of reduced cognitive aging.

The nutritional insurance argument is well supported. Ward (2014) analyzed NHANES data showing that multivitamin/mineral users had substantially lower rates of nutrient inadequacy for vitamins A, C, D, E, calcium, and magnesium compared to non-users. Blumberg et al. (2017) extended this analysis and found that without multivitamin use, a significant proportion of the U.S. population would fall below the Estimated Average Requirement for multiple micronutrients.

Conversely, the U.S. Preventive Services Task Force (2022) concluded that evidence is insufficient to recommend multivitamins for cardiovascular disease or cancer mortality prevention in the general population — a nuanced position that acknowledges the COSMOS and PHS-II findings while noting limitations. For specific populations — older adults, those with malabsorption conditions, individuals on restrictive diets, and people taking medications that deplete nutrients (e.g., PPIs depleting B12 per Lam et al., 2013) — the case for multivitamin use is considerably stronger.

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