March 28, 2022 2 min read
The underlying hypothesis for multivitamins being a benefit for cognition stems from evidence that essential nutrient deficiencies in B12, folate, vitamin D, and other micronutrients have been linked to accelerated cognitive decline and dementia in observational studies.
But there have been few randomized trials of these micronutrients and they have mostly tested individual micronutrients and not a comprehensive multivitamin supplement. The one previous large-scale trial of a multivitamin supplement began cognitive testing 2-3 years into the intervention, so it wasn't a full test of the hypothesis.
COSMOS-Mind includes 2262 men and women nationwide, all older than age 65 with a mean age of 73. They underwent repeated cognitive assessments beginning before randomization, a baseline assessment, and assessments at years 1, 2, and 3. The cognitive assessment was a well-validated, telephone-administered cognitive battery that included a composite global score, as well as assessment of episodic memory, executive function, and other domains.
They found that over the 3 years of treatment, participants who were randomized to multivitamins did significantly better than those randomized to a placebo. And the investigators estimated that multivitamins were slowing cognitive aging by 60% over the 3 years, reducing cognitive aging by 1.8 years. The subgroup with a history of cardiovascular disease at baseline seemed to have a particularly strong benefit from the multivitamins.
This is the first large-scale randomized trial suggesting efficacy of multivitamins in slowing cognitive aging. This would be a simple, safe and accessible intervention. However, it's important to keep in mind that these findings need to be replicated. If the findings are confirmed, multivitamin supplementation may become an important means of protecting brain health in older adults.
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