Approximately one-third of U.S. adults report taking multivitamins, data shows — but a new study suggests that the daily practice won’t extend longevity.
Researchers from the National Institutes of Health (NIH) analyzed more than 20 years’ worth of data from 400,000 healthy U.S. adults, concluding that taking multivitamins did not reduce mortality risk.
"The analysis showed that people who took daily multivitamins did not have a lower risk of death from any cause than people who took no multivitamins," the researchers wrote in a press release from NIH.
"There were also no differences in mortality from cancer, heart disease or cerebrovascular diseases."
Those who took daily multivitamins were actually found to have a 4% higher mortality risk, according to the study, which was published in JAMA Network Open on Wednesday.
The average age of participants was 61-½, and 164, 762 deaths occurred during the follow-up period.
Results were adjusted for factors including race, ethnicity, education and nutrition.
The study followed a 2022 analysis from the U.S. Preventive Services Task Force, which concluded that there was "insufficient evidence" to determine whether multivitamin use improved mortality.
By including larger numbers of participants and extending the follow-up for longer periods of time, the researchers aimed to account for potential biases that could have influenced the findings.
"For example, people who use multivitamins may have healthier lifestyles in general, and sicker patients may be more likely to increase their use of multivitamins," they wrote in a press release from NIH.
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Pieter Cohen, associate professor of medicine at the Cambridge Health Alliance in Massachusetts, was not involved in the study but offered his feedback.
"This study provides further evidence that taking multivitamins, even for 20 years or more, won't extend your life," he told Fox News Digital.
"For healthy adults, there's no reason to add on a multivitamin unless your doctor specifically recommends it."
Dr. Brett Osborn, a Florida neurologist and longevity expert, was also not involved in the study but weighed in on the findings.
"Key aspects of the study include its observational nature, the absence of a control group, and the variability in multivitamin formulations used by participants," he said in an email to Fox News Digital.
(The researchers also acknowledged these limitations in their discussion of the study results.)
"Observational studies like this one can suggest associations or correlations, but cannot prove causation due to the potential for confounding variables influencing both multivitamin use and mortality outcomes," Osborn said.
While the researchers noted that they had adjusted for factors such as demographics, lifestyle behaviors and health status, Osborn said, "residual confounding remains a concern."
The doctor also noted that lack of a control group makes it difficult to compare outcomes.
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"Without a control group, it's challenging to separate the effects of multivitamins from those of other health behaviors or baseline health conditions that could influence mortality," Osborn said.
The study also does not include controls for the specific formulation or dosage of multivitamins taken by participants, the doctor noted.
"Most multivitamins contain a broad spectrum of vitamins and minerals, but the concentrations can vary widely across brands and formulations," he said.
"Many commercially available multivitamins may not provide optimal levels of nutrients required for health benefits, potentially diluting any potential effects on longevity."
In his practice, Osborn said, he recommends a multi-capsule daily multivitamin to his patients.
Vitamin usage is just one aspect of longevity, the doctor pointed out, along with genetics, lifestyle, socioeconomic status and access to health care, among other factors.
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"The multifactorial nature of longevity means that isolating the impact of multivitamins alone is complex and challenging, if not impossible," Osborn said.
"There are just too many potentially confounding variables."
The study highlights the importance of "rigorous scientific inquiry" into the health benefits of multivitamins, according to the doctor.
"In my opinion, multivitamins should be taken, as most Americans are malnourished — certainly not calorically, but in the context of vitamins and minerals."
Looking ahead, the researchers emphasized the importance of measuring multivitamins’ impact on mortality in more diverse populations with different medical conditions and dietary habits.
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"It is important to evaluate multivitamin use and risk of death among different kinds of populations, such as those with documented nutritional deficiencies, as well as the potential impact of regular multivitamin use on other health conditions associated with aging," they wrote.
Fox News Digital reached out to the study researchers for comment, as well as the vitamin manufacturers PharmaVite (NatureMade), Nestlé Health Science (Garden of Life and Nature’s Bounty) and Life Extension.