A clinical trial with more than 2,000 participants has found that cognition and memory function improved in adults over the age of 65 after they took a daily multivitamin for a three-year period. The authors of the study, published today (September 14) in Alzheimer’s & Dementia, write that their results represent the first large, long-term trial indicating that a multivitamin can improve cognition in older adults, but they note that further work is needed to confirm their findings in a more diverse cohort and to identify the mechanisms behind the potential benefit.

“We are excited because our findings have uncovered a new avenue for investigation—for a simple, accessible, safe, inexpensive intervention that could have the potential to provide a layer of protection against cognitive decline,” study author Laura Baker, a gerontologist at Wake Forest University, tells CNN, adding that the results do not mean senior adults should start taking multivitamins to protect their cognitive health: “It’s too soon to make these recommendations.” 

The researchers separated the 2,262 participants ranging in age from 64 to 100 years—none of whom showed signs of cognitive impairment when they enrolled in the study—into four groups: one took a daily multivitamin plus a dose of cocoa extract containing flavonoids, another took only the cocoa supplement, a third took only the multivitamin, and the rest took only a placebo, reports STAT. The study was conducted as a so-called pragmatic trial, where researchers annually assessed participants’ cognitive function over mail and the phone—a practice designed to make research more accessible to those who couldn’t travel to the research site (though almost 90 percent of participants were white), the outlet reports.

See “Could Vitamin Supplementation Help Alzheimer’s Patients?

The results showed statistically significant improvements on brain function assessments in the groups taking multivitamins over the three years, whereas those taking only the cocoa extract showed no improvement, according to STAT. Scores improved even more in people with a history of cardiovascular disease, possibly because of the well-established link between heart and brain health, CNN reports. 

Not everyone agrees that the results have real-world implications, however. “You could score a point better when you take the test a year later, and it’s statistically significant,” Jeff Kaye, who directs Oregon Health & Science University’s aging and Alzheimer’s center and was not part of the study, tells STAT. “But does that translate into anything meaningful in a person’s life?”

To estimate the clinical implications of their findings, the researchers compared how brain function changed over time between the groups, and found that multivitamins appeared to slow cognitive aging by 1.8 years over the three years, or by 60 percent. However, the authors write this estimate is based on an “imprecise yardstick” and requires more research to confirm.

The researchers are planning a future trial, with more diverse participants, to investigate the biological mechanisms behind how multivitamins may lower the risk of cognitive decline, STAT reports. “There are multiple pieces of that puzzle that throughout life may be contributing to that risk in later life,” Baker tells the outlet. “This is a piece of that puzzle. But it is a complex puzzle.”