New data from the Cocoa Supplement and Multivitamin Outcomes Study (COSMOS) suggest that a daily multivitamin may help protect the aging brain. However, at least one expert has concerns about the study’s methodology and, as a result, the interpretation of its findings.
The meta-analysis of three separate cognition studies provides “strong and consistent evidence that taking a daily multivitamin, containing more than 20 essential micronutrients, can help prevent memory loss and slow down cognitive aging,” study investigator Chirag Vyas, MBBS, MPH, with Massachusetts General Hospital and Harvard Medical School, Boston, told this news organization.
“We are not now recommending multivitamin use, but the evidence is compelling that supports the promise of multivitamins to help prevent cognitive decline,” Dr. Vyas said.
The new data, from the cognitive substudies of COSMOS, were published online in the American Journal of Clinical Nutrition.
Clinically Meaningful Benefit?
To recap, COSMOS was a 2 x 2 factorial trial of coca extract (500 mg/d flavanols) and/or a daily commercial multivitamin-mineral (MVM) supplement for cardiovascular disease and cancer prevention among more than 21,000 US adults aged 60 years or older.
Neither the cocoa extract nor the MVM supplement had a significant impact on cancer or cardiovascular disease events.
COMOS-Mind was a substudy of 2262 participants aged 65 or older without dementia who completed telephone-based cognitive assessments at baseline and annually for 3 years.
As previously reported by this news organization in COSMOS-Mind, there was no cognitive benefit of daily cocoa extract, but daily MVM supplementation was associated with improved global cognition, episodic memory, and executive function. However, the difference in global cognitive function between MVM and placebo was small, with a mean 0.07-point improvement on the z-score at 3 years.
COSMOS-Web was a substudy of 3562 original participants who were evaluated annually for 3 years using an internet-based battery of neuropsychological tests.
In this analysis, those taking the MVM supplement performed better on a test for immediate memory recall (remembering a list of 20 words); they were able to remember an additional 0.71 word on average compared with 0.44 word in the placebo group. However, they did not improve on tests of memory retention, executive function, or novel object recognition.
The new data are from COSMOS-Clinic, an analysis of 573 participants who completed in-person cognitive assessments.
COSMOS-Clinic showed a modest benefit of MVM, compared with placebo, on global cognition over 2 years (mean difference, 0.06 SD units [SU]), with a significantly more favorable change in episodic memory (mean difference, 0.12 SU) but not in executive function/attention (mean difference, 0.04 SU), the researchers reported.
They also conducted a meta-analysis based on the three separate cognitive substudies, with 5200 nonoverlapping COSMOS participants.
The results showed “clear evidence” of MVM benefits on global cognition (mean difference, 0.07 SU; P = .0009) and episodic memory (mean difference, 0.06 SU; P =.0007), they reported, with the magnitude of effect on global cognition equivalent to reducing cognitive aging by 2 years.
In a statement, JoAnn Manson, MD, DrPH, chief of the Division of Preventive Medicine at Brigham and Women’s Hospital, who led the overall COSMOS trial, said that “the finding that a daily multivitamin improved memory and slowed cognitive aging in three separate placebo-controlled studies in COSMOS is exciting and further supports the promise of multivitamins as a safe, accessible, and affordable approach to protecting cognitive health in older adults.”