The study, which was funded by the US National Institute on Aging of the National Institutes of Health, included 2,200 participants aged 65 and older who were randomly assigned to take a daily multivitamin (Centrum Silver; Pfizer Consumer Healthcare, now Haleon) and/or a cocoa flavanol supplement from Mars Edge (a division of Mars), or placebo for three years.
While no cognitive benefits were observed in the cocoa flavanol group, significant benefits were recorded in those receiving the daily multivitamin.
“Our study showed that although cocoa extract did not affect cognition, daily multivitamin-mineral supplementation resulted in statistically significant cognitive improvement,” said Laura Baker, PhD, professor of gerontology and geriatric medicine at Wake Forest University School of Medicine and co-principal investigator of the trial. “This is the first evidence of cognitive benefit in a large longer-term study of multivitamin supplementation in older adults.”
Commenting independently on the study’s findings, Maria Carrillo, PhD, chief science officer for the US Alzheimer’s Association, said: “This is the first positive, large-scale, long-term study to show that multivitamin-mineral supplementation for older adults may slow cognitive aging. 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.
“Independent confirmatory studies are needed in larger, more diverse study populations. It is critical that future treatments and preventions are effective in all populations.”
“For now, and until there is more data, people should talk with their health care providers about the benefits and risks of all dietary supplements, including multivitamins.”
“We envision a future where there are multiple treatments and risk reduction strategies available that address cognitive aging and dementia in multiple ways — like heart disease and cancer — and that can be combined into powerful combination therapies… in conjunction with brain-healthy guidelines for lifestyle factors like diet and physical activity.”
Duffy MacKay, ND, Senior Vice President of Dietary Supplements at the Consumer Healthcare Products Association (CHPA), commented: “The promising results of this clinical trial – showing improved global cognition, episodic memory, and executive function in older adults after three years of daily multivitamin-mineral use – provides first-time evidence that dietary supplementation can be effective in helping older consumers protect and improve cognition.
“While there is no proven prevention or treatment for cognitive decline, we know that science grows in increments, and this study is one step toward reinforcing the beneficial role of a safe, accessible, and affordable dietary supplement that can be used to optimize health through self-care.”
Andrea Wong, PhD, senior vice president, scientific and regulatory affairs at the Council for Responsible Nutrition (CRN), stated: “This study adds to the body of evidence showing promise for various roles of multivitamins in health. Research has already established that multivitamins can help to fill nutrient gaps. Beyond this, the Physicians’ Health Study II, a large-scale clinical trial, showed an 8% reduction in overall cancer risk in older male physicians who took a daily multivitamin as well as a significant decrease in cataract risk.
"The COSMOS-Mind study provides evidence that daily multivitamin consumption may benefit cognitive function in older men and women. With further research, the full potential for multivitamins in protecting and enhancing health could be realized."
COSMOS-Mind was an ancillary study to the COSMOS trial led by Brigham and Women’s Hospital that randomized 21,442 men and women across the U.S. The study investigated whether taking a daily cocoa extract supplement or a daily multivitamin-mineral (MVM) supplement reduces the risk of developing heart disease, stroke, cancer and other health outcomes.
For the 2,200 participants of COSMOS-Mind, the data indicated that three years of multivitamin supplementation roughly translated to a 60% slowing of cognitive decline (about 1.8 years).
The researchers also noted that their results suggested that the cognitive benefits associated with multivitamin-mineral supplements may be more pronounced for older adults with CVD.
Vs. PHS II
In contrast, data from the Physician's Health Study II (PHS II), a large-scale, randomized, double-blind, placebo-controlled trial investigating the long-term effects of a common multivitamin in healthy, highly educated men did not find any cognitive health benefits (Annals of Internal Medicine, 2013).
However, Baker and her co-workers pointed out that there are key differences between the studies, which may explain the different results.
“In PHS II, the initial cognitive testing began an average of 2.5 years (range: 0.18–5.3 years) after randomization to MVM or placebo, nearly at the point in time when the final follow-up assessment was completed in COSMOS-Mind,” they explained. “Our data suggest that MVM treatment effects increased from baseline in the first 2 years and then remained stable between Years 2 and 3. As a result, any early cognitive benefits of MVM in PHS II would likely have been missed because of their assessment schedule given the COSMOS-Mind cognitive trajectory showing benefit within 2 years.”
Baker and her co-workers also explained that the multivitamin-mineral formulations used in the studies were different, with the COSMOS supplement containing lutein and lycopene, both of which were absent from the PHS II supplement. In addition, the amounts of vitamins D and K were 150%–300% higher in the COSMOS supplement, while vitamin A and minerals such as iron, magnesium, and copper were lower.
“Although some reports suggest cognition-protecting benefits of components that were at higher levels in the COSMOS MVM, no consensus has been reached about the role of specific supplement quantities for brain health,” they noted.
Benefits of cocoa flavanols
While the new COSMOS-Mind findings do not support a role for cocoa flavanols for cognitive function, other data from the bigger COSMOS study found that the cocoa flavanol supplement was associated with 27% reduction in deaths from cardiovascular disease (CVD).
Data published earlier this year in The American Journal of Clinical Nutrition indicated that the cocoa flavanol supplement led to a 10% decrease in the frequency of CVD events, including myocardial infarction (MI), stroke, coronary revascularisation, cardiovascular death, carotid artery disease.
Source: Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association
Published online ahead of print, doi: 10.1002/alz.12767
“Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial”
Authors: L.D. Baker, et al.