Based on a brain health and dietary supplements survey from 2019, more than half of adults take supplements, for one reason or another [1]. Many people are interested in how they can maintain their brain health and cognitive functions. Can dietary supplements be beneficial for brain health? A recent study reported that a daily multivitamin-mineral supplement taken for three years improved overall cognitive function [2]. However, taking cocoa extract for three years had no effect on cognitive functions.
These findings come from a large clinical trial called the COSMOS-Mind (COcoa Supplement and Multivitamin Outcomes Study of the Mind) which enrolled 2,262 older adults (mean age, 73 years old) [2]. Participants were randomly assigned to one of four groups: 1) two placebos (neither cocoa extract nor multivitamin-mineral), 2) cocoa extract and placebo (no multivitamin-mineral), 3) multivitamin-mineral and placebo (no cocoa extract), and 4) both cocoa extract and multivitamin-mineral. The cocoa extract (Mars Edge) contained 500 mg of cocoa flavanols and was taken once daily for three years. The multivitamin-mineral supplement (Centrum Silver) containing 30 vitamins and minerals was also taken once daily for three years. Participants took cognitive tests over the phone at the start of the study and annually for three years.
This study showed that daily intake of the multivitamin-mineral supplement resulted in a significant improvement on overall cognition, as well as improvements in specific functions such as memory and executive function (e.g., planning and decision-making), when compared to those receiving the placebo. Data modeling suggests that taking the multivitamin-mineral supplement for three years slowed cognitive aging by 1.8 years, or by 60%.
Interestingly, this effect on cognitive function was largest in participants with a history of cardiovascular disease, such as heart failure or ischemic attack. It is not known whether this more pronounced effect on cognitive function was due to a greater improvement in this group or the supplement conferring greater protection from cardiovascular disease-related cognitive decline. At the start of the study, people with a history of cardiovascular disease had lower cognitive functions compared to those without a history, so they may have had more room to improve. Based on observational studies, people with cardiovascular disease have micronutrient levels that are lower (e.g., vitamin D, vitamin K, and others) compared to those without cardiovascular disease, so the multivitamin-mineral supplement may have compensated for any deficiencies [3].
In contrast to the positive findings on the multivitamin-mineral supplement, taking the cocoa extract for three years had no effect on global cognition, memory, or executive function [2]. Previous evidence on cocoa extract supplements have been mixed, with some studies showing cognitive benefits and others showing no benefits [4; 5; 6].
The results related to the multivitamin supplement are encouraging. But it is worth emphasizing that it is a single study, and therefore findings are not definitive. An additional clinical trial is needed to confirm and extend these findings, particularly in a more diverse cohort of people. Previous studies of multivitamin-mineral supplements have reported inconsistent effects [7]. And the Global Council on Brain Health convened by the AARP concluded in 2019 that for most people, the best way to get nutrients important for brain health is from eating a healthy diet. If you are inclined to start taking supplements, ask your doctor or pharmacist about possible interactions with medications you are taking—as taking multiple drugs and supplements can increase your risk for side effects and adverse interactions, including cognitive impairment and delirium.
Yuko Hara, PhD, is Director of Aging and Alzheimer's Prevention at the Alzheimer's Drug Discovery Foundation. Dr. Hara was previously an Assistant Professor in Neuroscience at the Icahn School of Medicine at Mount Sinai, where she remains an adjunct faculty member. Her research focused on brain aging, specifically how estrogens and reproductive aging influence the aging brain's synapses and mitochondria. She earned a doctorate in neurology and neuroscience at Weill Graduate School of Medical Sciences of Cornell University and a bachelor's degree in biology from Cornell University, with additional study at Keio University in Japan. Dr. Hara has authored numerous peer-reviewed publications, including articles in PNAS and Journal of Neuroscience.
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