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Strong evidence16 studies

How we rate

“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.

Multivitamins

A supplement that combines vitamins and minerals in one daily dose. In older adults, it slightly slows down memory decline in the large COSMOS trial; it neither protects the heart nor prolongs life, and its effect on cancer is modest and contradictory.

Cognition

Benefits

In older adults, improves memory: in the COSMOS trial, daily supplementation improved immediate recall from one year onwards and throughout the three-year follow-up, the equivalent of 3.1 years of memory aging
The meta-analysis of the three cognitive studies from COSMOS confirms a benefit on global cognition and episodic memory, equivalent to two fewer years of cognitive aging
Modestly reduces the risk of total cancer in men: this is the result of the PHS II trial, which followed thousands of physicians for more than ten years, with no effect on prostate or colorectal cancers
Improves immediate recall memory according to a meta-analysis of ten randomized trials
In healthy women, mitigated fatigue and low mood caused by long tasks, and improved multitasking accuracy (placebo-controlled trial)

Precautions

No study summary in this fact sheet reports any adverse effects, but the tested products are not all the same: a result obtained with one does not necessarily apply to another. The limitations: no heart protection — neither fewer heart attacks, strokes or cardiovascular deaths in PHS II, nor fewer cardiovascular events in COSMOS, nor an association in a meta-analysis of 18 studies and more than two million participants. No longer life: in more than 390,000 adults followed for up to 27 years, taking multivitamins was not associated with lower mortality. Regarding cancer, the two major trials contradict each other: fewer cancers in PHS II physicians, no decrease in 3.6 years in COSMOS, and the US Preventive Services Task Force review, which associates multivitamins with fewer cancers, highlights significant limitations in this evidence. Regarding the brain, twelve years of multivitamins changed nothing for the cognition of PHS II physicians, and three years did not reduce the onset of mild cognitive impairment or dementia in COSMOS-Mind. The meta-analysis of ten trials finds nothing on delayed memory or verbal fluency. Finally, three years reduced neither hypertension nor blood pressure.

Recommended dosage

One dose per day, as in all major trials (PHS II, COSMOS). The tested products differ: no standard composition emerges from the studies in this fact sheet.

How to take it

For whom: the most robust positive results concern older adults (COSMOS). In younger adults, only a few short trials exist in this fact sheet.
Dose: one daily dose, as in all major trials. The tested products differ, and no standard composition emerges from the studies in this fact sheet.
How long: the effect on memory appears after one year in COSMOS and is maintained over three years. A single dose changed nothing in the cognition of women over 50.
What it does not do: neither fewer heart attacks or strokes, nor a longer life, nor less hypertension, according to the major trials and cohorts in this fact sheet.
Timing and meals: no study in this fact sheet compares morning to evening, nor taking it with or between meals.

Did you know?

The two largest trials contradict each other regarding cancer: in physicians followed for more than ten years, a daily multivitamin slightly reduced the risk; in older adults followed for 3.6 years in COSMOS, no decrease.

What the studies say

This study explored the effects of multivitamin-minerals (MVM) on cognitive function in older adults, using in-person assessments and a meta-analysis. Results from the clinical subgroup showed a slight benefit of MVM on global cognition and a significant improvement in episodic memory over two years. The meta-analysis of the COSMOS studies confirmed that MVMs benefit global cognition and episodic memory, with an effect equivalent to slowing cognitive aging by two years.
Vyas CM, Manson JE, Sesso HD, Cook NR, Rist PM, Weinberg A, Moorthy MV, Baker LD, Espeland MA, Yeung LK, Brickman AM, Okereke OI. — The American journal of clinical nutrition (2024) — View the source study

For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more