Vitamin supplements may slow cognitive decline in older adults

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Although some nutritional supplements are marketed for their protective properties against the effects of brain aging, research on this topic is inconclusive. A team of American scientists decided to evaluate the real effect of these multivitamin preparations in a three-year randomized clinical trial. The results suggest that daily multivitamin and mineral supplementation may slow cognitive aging.

Alzheimer’s disease and other forms of dementia affect more than 46 million people worldwide. To date, there is no treatment that prevents cognitive decline in asymptomatic elderly people. On the other hand, certain nutrients are known for their ability to preserve cognitive function. For example, cocoa is rich in flavanols—a subfamily of flavonoids—that, when consumed regularly, may slow cognitive decline by improving brain vasodilation, blood flow, and the formation of new blood vessels.

Vitamins and minerals are also known to target various biological pathways that support normal body and brain function; Thus, a deficiency in these nutrients may increase the risk of cognitive decline. Some studies have looked at the effects of certain vitamins (vitamin B9, vitamin D) and omega-3 on cognition, but the results have been inconclusive, partly due to design issues in these studies. COSMOS-Mind project (A study of the results of cocoa supplements and multivitamins) is the first large-scale, long-term study examining the effects of daily cocoa and/or vitamin and mineral supplementation.

No significant effects of cocoa on cognition

This study is actually an add-on to another placebo-controlled clinical trial (COSMOS) examining the effects of daily consumption of cocoa extract and a commercial multivitamin and mineral preparation on cardiovascular and cancer risk.

The COSMOS-Mind study involved more than 2,200 participants with an average age of 73, of whom 60% were women. They were in good health (no recent stroke or cancer or serious illness) and had not taken any nutritional supplements before the study. They were divided into four groups: one took cocoa extract and a vitamin preparation daily; the second group took cocoa extract and a placebo; the third group took a placebo and vitamin preparations; finally, the last group had only placebo. Self-reported adherence was similar across groups (most took more than 75% of tablets during the study).

Cocoa extract contained 500 mg of flavanols, including 80 mg of epicatechins and small amounts of theobromine (about 50 mg) and caffeine (about 15 mg), which may potentiate the central and vascular effects of flavanols. The multivitamin preparation was typical of commercial products; it contained vitamins (mainly A, D, K and B9), calcium, magnesium, phosphorus, chromium, molybdenum, lutein, lycopene, etc.

Participants’ cognitive abilities were assessed by telephone interview at the beginning of the study and then annually for three years. These interviews aimed to assess general cognitive status, episodic memory, and executive functions. Tests included short-delayed word list recall (10 minutes), additional long-delayed word list recall (40 minutes), immediate and delayed story recall, and an assessment of the participant’s verbal fluency.

The results of the study show that the scores obtained by the participants who consumed the cocoa extract (or its placebo) did not differ significantly; Therefore, cocoa consumption appears to have no effect on cognition.

Vitamins that preserve memory and executive functions

On the other hand, the scores of the participants who took the vitamin and mineral supplements showed a “significant therapeutic effect” compared to the placebo, the researchers point out in their article. The team also notes that this effect was most pronounced in participants with cardiovascular disease.

affects cocoa vitamin cognition
Development of global cognition in participants who received cocoa extract compared to those who received placebo (A) and participants who received a multivitamin preparation compared to those who received placebo (B). © L. Baker et al.

Vitamins and minerals moderately improved memory and executive functions. There was no evidence of an interaction between cocoa extract supplementation and vitamin supplementation on global cognition or memory and executive function. In other words, cocoa extract had no effect on the cognitive effects of the vitamins. The mechanisms by which these vitamins preserve cognitive function remain to be determined.

Although the Alzheimer’s Association is encouraged by these findings, we are not ready to recommend the widespread use of multivitamin supplements to reduce the risk of cognitive decline in the elderly. », said Dr. Maria C. Carrillo, chief researcher of the association. Independent confirmatory studies in larger and more diverse populations are needed before any recommendation can be made. If the effect holds true, older people would have a simple and inexpensive way to preserve their cognitive abilities.

Meanwhile, the Alzheimer’s Association encourages patients to discuss the benefits and risks of all nutritional supplements, including multivitamins, with their doctors and pharmacists. Excesses of certain nutrients can actually have harmful effects: excessive absorption of vitamin D, for example, can cause hypercalcemia, and high doses of vitamin C can cause gastrointestinal upset.

Source: L. Baker et al., Alzheimer’s & Dementia

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