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RCT finds multivitamins but not cocoa extract improves global cognition

Rod Tucker
22 September, 2022  

Daily multivitamins and minerals but not a cocoa extract led to an improvement in global cognition in older adults according to a recent RCT

Taking a multivitamins and mineral supplement every day rather than a cocoa extract for up to three years, leads to an improvement in global cognition, episodic memory and executive function in older adults according to the results of a randomised, controlled trial by a team of US researchers.

Currently more than 55 million people live with dementia worldwide, and there are nearly 10 million new cases every year. Mild cognitive impairment describes a condition in which individuals demonstrate cognitive impairment but with minimal impairment of instrumental activities of daily living and can be the first cognitive expression of Alzheimer disease. However, currently, there are no approved treatments for mild cognitive impairment but studies have examined the potential value of using cocoa extracts. For example, there is some data to suggest that flavonoids (which are present in cocoa extract) have the potential to prevent the progression of neurodegenerative pathologies and to promote cognitive performance. In addition, other evidence has revealed a positive effect of cocoa polyphenols on memory and executive function. But not studies have been positive and other work in healthy older adults suggested no effect from an eight-week intake of dark chocolate flavanols on cognition. The effect of multivitamins on cognition is even less clear particularly as many trials have examined the impact of individual vitamins. Nonetheless, one randomised, double-blind placebo-controlled trial found that in male physicians aged 65 years or older, long-term use of a daily multivitamin did not provide cognitive benefits.

But whether the combination of multivitamins and minerals together with a cocoa extract could positively impact on cognition remains unclear and was the subject of the current study. Using a 2 x 2 factorial design, the US researchers undertook the COSMOS-MIND trial which was an ancillary study to the large-scale COSMOS trial, designed to assess if a cocoa extract and a multivitamin-mineral tablet reduced the risks for major cardiovascular events and total invasive cancer. COSMOS-Mind used a telephone-based interview to assess cognitive function and impairment to determine whether cocoa flavanols or a vitamin supplement might benefit cognitive function in adults aged 65 years or older over 3 years of annual follow-up. Participants were randomised to four groups: a cocoa extract (CE) placebo/multivitamin mineral (MVM) placebo; CE-MVM placebo; CE placebo-MVM; CE-MVM. Testing included a baseline telephone interview of cognitive status (which excluded those is existing cognitive impairment), word list and story recall (assessing episodic memory), oral trail-making, verbal fluency, number span and digit ordering (which together served as an executive function composite). The primary outcome was a global cognition composite formed from the individual tests and reported as a z-score so that higher scores were reflective of better performance.

Multivitamins and global cognition

A total of 2262 participants with a mean age of 72.97 years (40.4% male) were included and randomised to the four groups.

For those in the CE group, the mean change in the z-score (compared to placebo) was 0.03 (95% CI -0.02 – 0.08, p = 0.28). However, when the researchers looked at the effect of using multivitamins, the mean change z-score was 0.07 (95% CI 0.02 – 0.12, p = 0.007). In further analysis, it became clear that this effect was larger for those with a history of cardiovascular disease (no history: 0.06; with history: 0.14).

The CE also had no effect on the episodic memory or the executive function composites. In contrast, the multivitamins mineral supplement improved episodic memory (mean change z-score = 0.06, p = 0.04) and for the executive function (mean change z-score = 0.06, p = 0.02).

The authors concluded that daily intake of a CE for 3 years did not positively affect global cognition whereas their trial provided the first evidence that a low-cost multivitamin-mineral supplement had the potential to improve cognitive function in older adults.

Citation
Baker LD et al. Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial Alzheimers Dement 2022