In a new study published Wednesday in Alzheimer's & Dementia, researchers from Wake Forest University found a "promising" link between multivitamins and cognition and memory in older adults.
Study details and key findings
For the study, researchers followed 2,262 individuals enrolled in the COSMOS-Mind trial, which lasted for three years. On average, participants were 73 years old. In addition, 60% were women and 89% were white. None of the participants had a history of myocardial infarction or stroke.
To test whether two measures could improve cognition in older adults, participants were randomly assigned to one of four groups using a two-by-two factorial design. The first measure, a daily dose of 500mg cocoa extract capsules, and the second measure, a common multivitamin called Centrum Silver, were given to participants randomly assigned to receive treatment.
One group of participants took a daily dose of cocoa extract and Centrum Silver, one group took two placebos, another took Centrum Silver and a placebo of cocoa extract; and the final group took cocoa extract with a placebo of Centrum Silver.
To assess cognition over time, researchers conducted phone interviews at the start of the trial and every year for three years. They created a global cognition composite based on mean z scores from individual tests, including the Telephone Interview of Cognitive Status, Word List and Story Recall, Oral Trail-Making, Verbal Fluency, Number Span, and Digit Ordering.
Participants who received a daily dose of cocoa extract did not see any additional relative to the groups who did not take cocoa extract. However, the researchers found a statistically significant increase in the cognitive score of participants who took Centrum Silver. Among participants who took the multivitamin, the most significant benefits seemed to be among those with a history of cardiovascular disease.
Episodic memory and executive function also improved.
Notably, many participants who received a daily placebo also improved their scores, with higher scores one and two years after the trial began. However, study author Laura Baker noted that this is a well-known occurrence with these types of cognitive tests.
"Their scores are actually improving, but it's not because they're getting smarter. It's because they're more familiar with the test," Baker said.
The key thing, Baker added, is to compare the rise in scores of people in the placebo group with those who are on a multivitamin. After two years, cognitive scores leveled out for both groups, but remained higher among those on multivitamins through year three.
While the study's findings seemed promising, they also posed several unanswered questions. "While the Alzheimer's Association is encouraged by these results, we are not ready to recommend widespread use of a multivitamin supplement to reduce risk of cognitive decline in older adults," said Alzheimer's Association chief science officer Maria Carrillo.
"Independent confirmatory studies are needed in larger, more diverse study populations," Carrillo noted. "It is critical that future treatments and preventions are effective in all populations."
The study authors noted that COSMOS-Mind had several limitations. In particular, they highlighted that the participants were responsible for self-reporting their adherence to their assigned treatments, making it difficult to ensure accuracy.
The researchers did not determine which ingredients in Centrum Silver led to improved cognition. And they did not have biomarker and genetic information about participants.
Still, Baker noted that "[t]his is the first evidence of cognitive benefit in a large longer-term study of multivitamin supplementation in older adults."
However, she warned that it is too soon to recommend a daily multivitamin to prevent cognitive decline.
"While these preliminary findings are promising, additional research is needed in a larger and more diverse group of people," Baker said. "Also, we still have work to do to better understand why the multivitamin might benefit cognition in older adults." (Wosen, STAT, 9/14; George, MedPage Today, 9/15)