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22nd September 2022
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.
Baker LD et al. Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial Alzheimers Dement 2022
24th March 2022
The use of a cocoa extract containing flavanols did not reduce the overall incidence of cardiovascular events but did lower the incidence of cardiovascular deaths. This was the main finding of a randomised trial by researchers from the Division of Preventive Medicine, Brigham and Women’s Hospital, Boston, US.
Flavan-3-ols, which are a subclass of flavonoids, represent a type of poly-phenolic substances which are present in a range of plants such as cocoa and cocoa containing foods such as chocolate. Furthermore, research demonstrates a beneficial effect of cocoa on blood pressure, insulin resistance, and vascular and platelet function.
As well as flavonoids, a cocoa extract typically contains other ingredients such as epicatechin and the methylxanthines, theobromine and caffeine. In fact, studies suggest how the presence of these latter components mediate an increased plasma concentration of epicatechin metabolites that coincides with enhanced vascular effects.
To date, much research which has focused on the cardiovascular effect of cocoa containing products such as chocolate, and suggests a small inverse association between consumption and both coronary heart disease and stroke.
However, there is a lack of data from large-scale trials, on the cardiovascular benefits of a flavanol-rich cocoa extract which contains all the bioactive compounds present in the cocoa bean.
As a result, the US team undertook the Cocoa Supplement and Multivitamin Outcome Study (COSMOS), a pragmatic, randomised trial which sought to examine the effect of a cocoa extract on cardiovascular disease and cancer in older adults. For the present study, the authors have only reported on the cardiovascular outcomes.
The team recruited adults over 65 years of age, who were initially free of major cardiovascular disease and given either a cocoa extract containing 500 mg/day of cocoa flavanols and a multivitamin supplement or matching placebo.
All participants were required to stop taking cocoa supplements (although chocolate could still be eaten) and a blood biomarker of flavanol intake were initially measured and repeated after years 1, 2 and 3. The primary outcome was a composite of total cardiovascular disease (CVD) outcomes including myocardial infarction (MI), stroke, cardiovascular mortality and coronary revascularisation.
The authors then set the secondary outcomes as the individual components of the primary outcome, i.e., cardiovascular death, stroke etc.
Cocoa extract and cardiovascular outcomes
A total of 21,442 individuals with a mean age of 72.1 years (59.1% female) were randomised to cocoa (10,719) or placebo and followed for a median of 3.6 years. Based on an analysis of plasma samples, there was a three-fold higher increase compared to placebo, in the levels of flavanol biomarker and this did not differ between follow-up assessment.
During the follow-up period there were 866 confirmed cardiovascular events, 410 in those taking the cocoa extract and 456 in the placebo group, giving a hazard ratio, HR of 0.90 (95% CI 0.78 – 1.02, p = 0.11).
For the secondary outcomes, only cardiovascular death was significantly different (HR = 0.73, 95% CI 0.54 – 0.98).
The authors concluded that while the cocoa extract did not reduce the primary outcome, longer follow-up of trial participants may further elucidate the relationship between consumption of the extract and cardiovascular events.
Sesso HD et al. Effect of Cocoa Flavanol Supplementation for Prevention of Cardiovascular Disease Events: The COSMOS Randomized Clinical Trial Am J Clin Nutr 2022