Multivitamin & Minerals
Is taking a daily multivitamin actually worthwhile?
For years, the conventional advice has been that most people who eat a reasonably healthy diet don't need a multivitamin. But the question becomes more interesting as we get older.
Our diets may not always provide optimal amounts of every nutrient, and our ability to absorb or use certain nutrients can change with age. Medications and health conditions can also affect nutritional needs.
More recently, several large studies of older adults have raised another intriguing possibility: a daily multivitamin may have a modest benefit for memory and cognitive aging.
That doesn't mean everyone should take one. But it makes multivitamins worth another look.
The important questions are what benefits a multivitamin may provide, how strong the evidence is, and whether supplementation becomes more valuable as we age.
What Does a Multivitamin Actually Provide?
A multivitamin is essentially nutritional insurance. It usually provides many of the vitamins and minerals the body needs in relatively modest amounts.
Most contain vitamins A, C, D, E and K, the B vitamins, and minerals such as zinc, selenium and iodine. Vitamin D and magnesium are also worth examining individually because their potential benefits and limitations differ.
A multivitamin isn't a substitute for a healthy diet. Food provides protein, fiber, healthy fats and thousands of other compounds that aren't contained in a pill.
The more interesting question is whether a multivitamin can fill small nutritional gaps that accumulate as we get older—and whether doing so produces measurable health benefits.
That is where the recent research gets interesting.
What Did the COSMOS Study Find?
The most interesting recent evidence comes from COSMOS, a large randomized, placebo-controlled study of older adults.
In three separate COSMOS studies, researchers compared people taking a daily multivitamin/mineral with people taking a placebo. When researchers combined the results from more than 5,000 participants, they found a small but statistically significant benefit in overall cognition and memory.
The researchers estimated that the difference in overall cognition was equivalent to about two years less cognitive aging.
That's intriguing, but it shouldn't be interpreted as showing that a multivitamin prevents Alzheimer's disease or dementia. The studies measured changes in cognitive performance, not whether participants developed dementia.
The multivitamin used in COSMOS was Centrum Silver, although the study does not tell us which vitamin or mineral—or combination—might have produced the benefit.
Would a Better Multivitamin Work Better?
COSMOS used Centrum Silver, a relatively basic multivitamin. Other multivitamins contain different forms and amounts of vitamins and minerals, and some provide nutrients not found—or found only in small amounts—in Centrum Silver.
That raises an interesting question: If Centrum Silver produced a modest cognitive benefit, would a more comprehensive multivitamin produce a larger benefit?
We don't know. COSMOS tested one particular product, and the researchers could not determine which nutrients were responsible for the benefit. A different formulation might be better, no different—or potentially worse if it provides excessive amounts of some nutrients.
For now, the strongest evidence is surprisingly specific: a relatively ordinary multivitamin produced a measurable benefit in several randomized studies of older adults.
Who Might Benefit Most?
A multivitamin may be most useful for people whose diets don't consistently provide enough vitamins and minerals.
That can become more relevant as we get older. Appetite and food intake may decline, absorption of some nutrients can become less efficient, and medications or health conditions can affect nutritional needs.
People who restrict certain food groups may also have nutritional gaps that are difficult to fill consistently through diet alone.
A multivitamin doesn't guarantee better health, and taking more isn't necessarily better. But for some older adults, a well-formulated multivitamin/mineral may provide a practical way to help fill nutritional gaps.
Risks and Cautions
A standard multivitamin is generally considered safe for most people, but more is not necessarily better. High doses of some vitamins and minerals can cause problems, particularly when several supplements containing the same nutrients are taken together.
Some nutrients can also interact with medications. Vitamin K, for example, can interfere with warfarin and similar anticoagulants.
The label matters. Rather than simply looking for the longest ingredient list or the highest doses, it makes sense to consider what is included, how much, and whether it duplicates other supplements you already take.
Learn More
A clear overview from the NIH Office of Dietary Supplements covering what multivitamins contain, who might benefit, safety, and what research shows about their health effects.
The 2024 randomized COSMOS study and meta-analysis that found modest benefits from daily multivitamin/mineral supplementation for overall cognition and episodic memory in older adults.