Daily multivitamin may improve memory, help slow cognitive decline

The new study is a second, parallel trial accompanying the recently completed COcoa Supplement and Multivitamin Outcomes Study Web, or COSMOS-Web study. Its larger aim was to investigate the beneficial memory effects of multivitamins and cocoa flavanols. But the current study reports only the effects of taking multivitamins.

For the study, 3,562 older adults were randomly assigned to one of two groups. The first took a daily multivitamin — Centrum Silver for adults — over the course of the three-year study. The second group took a placebo.

Each year, participant memories were assessed via online neuropsychological tests. The researchers were primarily interested in measuring the strength of individuals’ episodic memory, or immediate recall.

After 1 year of taking multivitamins, study participants experienced a modest improvement in memory that was the equivalent of turning back the clock by about 3.1 years compared to a control group.

The authors of the study found the most significant memory improvement occurred in people with underlying cardiovascular disease. The reason for this isn’t clear, though the researchers suspect it may have to do with a pre-existing nutrient deficit.

As a secondary goal, the researchers also searched for changes in episodic memory over the study period, and participants’ performance of novel object recognition and executive function. However, they found multivitamins had no effect on these particular neuropsychological tasks.

Study co-author Dr. JoAnn Manson, MPH, epidemiology professor at the Harvard T.H. Chan School of Public Health, told Medical News Today:

“Preserving memory and cognitive health is a high priority for most midlife and older adults. Few previous strategies have been rigorously tested in randomized clinical trials and shown to have cognitive benefits.”

Dr. Manson explained that the results of the study are particularly persuasive in that they represent the concurrent findings from two separate trials at once.

Both trials found that multivitamins slowed down cognitive decline in the short, three-year term.

Matthew Pase, PhD, associate professor at the Turner Institute at Monash University and Harvard T.H. Chan School of Public Health, not involved in the study, noted that “boosting cognition in the short term is rather different to preventing cognitive decline in the long term, and there are few long-term randomized controlled trials.”

Dr. Fernando Testai, professor of neurology University of Illinois at Chicago, also note involved in the research, told MNT that prior “studies examining the preventive effects of vitamin and mineral supplementation on cognitive decline have produced inconsistent outcomes.”

Dr. Testai suggested such research is complicated by a number of factors that may affect cognitive performance, including:

• genetic factors
• coexisting vascular risk factors
• social determinants of health
• unhealthy behaviors (i.e., sedentary lifestyle, alcohol use, and smoking)

The study does not explore exactly which vitamins within the multivitamin played a role in supporting memory.

“Multivitamins contain more than 20 essential vitamins and minerals, and the specific micronutrient conferring cognitive benefits cannot be determined when a combination tablet is administered,” Dr. Manson explained.

Dr. Pase noted that if one person is low on one vitamin, and another person lacks another vitamin, a multivitamin could help them both.

As for what it is about multivitamins that helped the study participants, Dr. Testai suggested a few possibilities.

“The deficiency of several vitamins and minerals, including B vitamins, vitamin D, zinc, and iron, has been associated with cognitive decline,” he said, adding that research has shown that vitamin E may have neuroprotective properties.

Dr. Manson said that a daily multivitamin may be a good idea based on the COSMOS-Web studies.

“Our findings suggest that multivitamin supplementation holds promise as a safe, accessible, and affordable approach to protecting cognitive health in older adults,” Dr. Manson noted.

“A standard daily multivitamin for adults, providing the daily intake values for essential vitamins and minerals, should show similar results,” she added.

Dr. Pace said the study was valuable but he would not recommend multivitamins for slowing cognitive decline.

He noted that their benefit in the study was limited to just one cognitive area, and that he would prefer to see the results of longer studies and “improvements on a greater range of cognitive tasks.”

He added that “it is important to note that not all vitamin supplements (or even multivitamins) are created equal.” Indeed, dietary supplements, including multivitamins, are not approved by the U.S. Food and Drug Administration (FDA) for safety or effectiveness.

To that end, Dr. Testai cautioned that “excessive levels of certain micronutrients, especially fat-soluble vitamins, lead, and iron, can lead to toxicity.”

Still, Dr. Manson was less concerned, pointing out, “An advantage of multivitamins is that these supplements provide daily intakes and do not involve mega-dosing.”

“Multivitamins (and other dietary supplements) shouldn’t be perceived as a substitute for a healthy diet or healthy lifestyle, even if used as a complementary approach,” Dr. Manson concluded.