For many of us, taking a multivitamin has become a rather ordinary part of the day.
Maybe you grew up being handed a colourful vitamin gummy because it was supposedly good for you, with the added benefit of tasting quite nice. Or perhaps, now that you’re an adult with an increasingly hectic lifestyle, taking a multivitamin alongside breakfast feels like a simple way of looking after your health and well-being.
I’ve noticed this among my own friends too. There seems to be a fairly common understanding that multivitamins help keep us healthy, protect us against diseases and possibly even contribute to living a longer life.
And honestly, the idea sounds quite appealing. One little tablet covering all those nutritional bases? Amazing!
But do multivitamins actually deliver those benefits? Can they protect us against serious diseases, or are we expecting a little too much from just one daily pill?
The Short Answer
Probably not in the way that you’d expect it to.
For generally healthy adults, research hasn’t found convincing evidence that taking a daily multivitamin helps you live longer or reliably protects against cardiovascular disease or cancer types.
There are some interesting findings, particularly regarding cognitive health in older adults, but the overall picture is much less impressive than multivitamin marketing might suggest to us when shown in advertising on tv or on social media.
So in plain English: Taking a multivitamin isn’t automatically a bad decision. But if you’re already eating adequately and generally taking care of your health, there isn’t strong evidence that adding one will give you extra years of life or protect you from getting sick.
What Does The Evidence Actually Say?
To start with, let us break it down into the two components: Let’s start with the question of living longer.
A large 2024 study by Loftfield and colleagues followed 390,124 adults across three US cohorts, with more than 20 years of follow-up.
The researchers compared people who regularly took multivitamins with those who didn’t. Interestingly, multivitamin users often had other favourable health characteristics, including better dietary habits and lower rates of smoking.
Yet despite this, regular multivitamin use was not associated with a longer life.
In fact, daily users showed a slightly higher mortality risk in some analyses. The important distinction here is that this was an observational study, meaning we cannot conclude that multivitamins caused those deaths.
Ok, component two: What about actual disease prevention?
The COSMOS randomized trial, published by Sesso and colleagues in 2022, investigated 21,442 older adults who were assigned to take a daily multivitamin or placebo.
After a median follow-up of 3.6 years, the researchers found no statistically significant reduction in overall invasive cancer, cardiovascular events or mortality.
There was an interesting reduction in lung cancer within a secondary analysis, although the trial’s main cancer outcome remained negative.
And the broader 2022 USPSTF evidence review adds another layer. When researchers pooled several randomized trials, multivitamins were associated with a small reduction in overall cancer incidence, but not a clear reduction in cancer deaths, cardiovascular disease or overall mortality.
So while the evidence isn’t entirely negative, it also doesn’t support the idea that taking a multivitamin can act as an all encompassing protective agent against diseases.
🔬 For the curious: But aren’t vitamins essential?
That is absolutely right! Vitamins and minerals are involved in countless processes our bodies rely on. Without adequate amounts, our health can suffer.
The thing I want to stress is, that needing vitamins isn’t necessarily the same as needing vitamin supplements.
There’s a difference between correcting a nutritional deficiency and taking additional vitamins when your nutritional needs are already being met.
Most of the disease-prevention research we’re discussing concerns people without known deficiencies.
So if someone genuinely needs supplementation because of a deficiency, pregnancy-related requirements or another medical reason, that is a different situation entirely.
What Changes The Answer?
As with most research, the studies aren’t perfect.
The enormous Loftfield study was observational. Even when researchers account for factors like smoking, diet and education, there may still be differences between people who take multivitamins and those who don’t. In observational studies it is impossible to factor in every little thing that could’ve led to a change in the answer.
Randomized trials help address that problem, but they come with limitations of their own.
For example, the COSMOS trial followed participants for a median of just 3.6 years. That’s a respectable amount of time, but diseases such as cancer can take decades to develop. The researchers themselves acknowledged that longer follow-up could reveal effects not captured during the trial.
We also need to consider who was studied. Many participants were older adults, and the findings won’t necessarily apply equally to younger people or those with particular nutritional needs.
And finally, we’re talking about several different outcomes here. Living longer, preventing cancer and maintaining cognitive function are not interchangeable measures of health.
What Does This Mean In Real Life?
If you already take a multivitamin, enjoy doing so and have no medical reason to avoid it, these findings don’t mean you automatically need to throw the bottle away cause there’s no benefit and it just costs you that extra $.
But they do challenge the idea that a multivitamin is a reliable insurance policy against an unhealthy lifestyle or other daily choices that favor different illnesses.
Supplements are not a replacement for a balanced diet, physical activity, adequate sleep and other established health behaviours.
And if you’re concerned that your diet isn’t meeting your nutritional needs, it may be more useful to figure out which nutrients you’re actually missing, rather than assuming a general multivitamin will solve every problem. In addition to that being an issue that absolutely needs to be addressed by a physician.
🕳️ 🐇 Rabbit Hole: Could Multivitamins Actually Help Our Brains Age More Slowly?
Now this is where we get another interesting rabbit hole to go down again!
Although multivitamins haven’t shown a convincing benefit for living longer, a 2024 study by Vyas and colleagues found something rather promising regarding cognitive aging.
In a smaller COSMOS subgroup of 573 older adults, daily multivitamin supplementation was associated with improvements in episodic memory over two years compared with placebo.
The researchers also combined results from three COSMOS cognitive substudies, involving more than 5,000 non-overlapping participants, and found modest improvements in global cognition and memory.
They estimated that the difference in global cognitive performance was equivalent to roughly two years less cognitive aging.
That’s quite an interesting result! But unfortunately, there are still a few things that we should consider before we take out the car keys to drive to the next pharmacy.
The improvements were relatively small, and the researchers did not establish that multivitamins prevent dementia or other neurodegenerative diseases. The findings also specifically concern older adults.
Still, it’s a useful reminder that a supplement can show potential benefits in one area without necessarily improving every aspect of health.
EVIDENCE VERDICT
A substantial evidence base, but limited benefits for general disease prevention.
How convincing is the evidence?
●●●○○
We have large observational studies, randomized trials and systematic evidence reviews.
The cognitive results in older adults are promising, though more research is needed to establish their long-term clinical importance.
For the question of whether multivitamins help generally healthy adults live longer, the findings are reasonably consistent: a clear longevity benefit has not been demonstrated.
A similar situation exist for whether it can prevent different types of cancer, too.
Does it change what we should do?
Again, probably not dramatically. If you have an identified nutritional deficiency or increased nutritional requirements, appropriate supplementation may be important.
If you’re taking a multivitamin purely because you believe it guarantees better health or a longer life, however, the current evidence doesn’t really support that line of thought.
The Bottom Line
Multivitamins certainly have their uses, particularly when someone needs help meeting specific nutritional requirements.
But for generally healthy adults, taking one every morning hasn’t convincingly been shown to prevent major diseases or extend life. Some smaller benefits may exist, and research into cognitive aging gives us an interesting reason to keep investigating.
For now, though, a multivitamin is not a substitute for the other things we already know support good health.
It may have a place in your routine. Just don’t expect it to do all the heavy lifting.
References & Sources
View the studies behind this article
- O’Connor EA, Evans CV, Ivlev I, et al.
Vitamin, Mineral, and Multivitamin Supplementation for the Primary Prevention of Cardiovascular Disease and Cancer: A Systematic Evidence Review for the U.S. Preventive Services Task Force.
Rockville (MD): Agency for Healthcare Research and Quality (US); 2021 Jun. (Evidence Synthesis, No. 209.)
[Read the Source] - Sesso HD, Rist PM, Aragaki AK, Rautiainen S. et al.
COSMOS Research Group. Multivitamins in the prevention of cancer and cardiovascular disease: the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial.
Am J Clin Nutr. 2022
[Read the Study] - Loftfield E, O’Connell CP, Abnet CC, et al.
Multivitamin Use and Mortality Risk in 3 Prospective US Cohorts.
JAMA Netw Open. 2024
[Read the Study] - Chirag M Vyas et al.
Effect of multivitamin-mineral supplementation versus placebo on cognitive function: results from the clinic subcohort of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial and meta-analysis of 3 cognitive studies within COSMOS
The American Journal of Clinical Nutrition
[Read the Study] - U.S. Preventive Services – Task Force
Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: Preventive Medication
[Read the Source]
Written by A Dose of Proof
Health research can be fascinating — but the way it’s written often makes it much harder to understand than it needs to be.
A Dose of Proof is the voice behind After the Abstract, translating health research into clear, evidence-focused explanations that look beyond the headline — including what a study found, what it didn’t prove, and whether the results actually matter.
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