In a recent study published in The American Journal of Clinical Nutrition, researchers investigated whether regular coffee extract (CE) supplementation could improve cognitive performance over a two-year period.
The fastest-growing age segment in the US is adults aged ≥65 years who are at high risk for developing Alzheimer's disease and related dementias (ADRDs). A decrease in cognitive function during aging could increase ADRD risk. Interventions targeting the earliest signs of age-related cognitive decline may help preserve cognitive function. Previous randomized clinical trials have shown promising findings about the effects of cocoa extract on late-life cognition. A long-term RCT using offline neuropsychological tests may clarify CE's cognitive effects.
Study: Effect of cocoa extract supplementation on cognitive function: results from the clinic subcohort of the COSMOS trial. Image Credit: Neirfy / Shutterstock
About the study
In the present study, researchers evaluated the impact of regular coffee extract supplementation on cognition over two years in 573 older individuals from the clinical subgroup of the COCOa Supplement and Multivitamin Outcomes Study (COSMOS trial, subgroup COSMOS-Clinic) and underwent offline, detailed neuropsychological tests.
The COSMOS trial is a 2x2 factorial randomized controlled trial examining the impact of a daily coffee extract [comprising 500 mg flavanols and 80 mg (–)-epicatechin) and a multivitamin-mineral supplement (MVM) on cardiovascular disease and cancer prevention among 21,442 US adults aged 60. The study included 573 participants in the clinic sub-cohort, with 492 completing two-year follow-up assessments.
The trial excluded individuals with a history of stroke, myocardial infarction, cancer, or other serious diseases, unwillingness to discontinue multivitamins, vitamin D, and CE supplementations during the trial, extreme caffeine sensitivity, less than 75% adherence to study medications over ≥2.0 months of placebo run, and those who could not speak English.
The present study included 603 individuals from the COSMOS-Clinic who resided in greater Boston to undergo health assessments and specimen collection at study initiation and two years. The study included individuals without significant hearing impairment who finished a 45-minute neuropsychological evaluation battery.
The primary outcome was the global cognition composite, averaging z-scores of 11 tests: 3MS; Consortium to Establish a Registry for Alzheimer's Disease (CERAD) total learning, delayed recall, and recognition; instantaneous and delayed East Boston Memory Test (EBMT) recall trials; two assessments of categorical fluency (naming vegetables and animals, Trail Making Test (TMT) Parts A and B; and the Digit Span Backward assessment.
The secondary study outcomes included composite measures of episodic memory (z-scores from four assessments: EBMT and CERAD instantaneous and delayed recalls; and executive/attention function composite measure (z-scores from five tests: two categorical fluency, Digit Span Backwards test, TMT-Part A, and TMT-Part B).
The team explored potential modifying roles of baseline factors, including diet and flavanol status, on the effects of coffee extract and placebo on cognition. The researchers stratified the primary analyses by habitual diet quality or habitual flavanol consumption. In the subgroup analyses, the team addressed whether design variables and subgroups chosen a priori according to their relevance in cognitive decay and Alzheimer's disease and related dementia risk modified the effects of CE, compared to placebo, on global cognition over two years.
In the post-hoc analysis, the team reran the primary analyses evaluating the effects of treatment on domain-specific and global cognitive scores after adjusting for additional potential confounding variables significantly differing between the study groups.
Results
The mean participant age was 70 years; 49% were female; 54% had received postbaccalaureate education, and 11% reported pre-randomization daily chocolate consumption. Of the 603 participants, 573 completed all baseline cognitive evaluations, and 14% were lost to follow-up. Among the participants, 285 and 288 comprised the CE and placebo groups, respectively. At one year, 98% of coffee extract and 96% of placebo recipients complied with the interventions, while at two years, 91% of both groups exhibited satisfactory adherence.
The study showed no significant effects of coffee extract supplementation on two-year changes in global cognition, episodic memory, or executive function/attention. However, subgroup analyses indicated the cognitive benefits of coffee extract supplementation among those with poorer baseline diet quality. However, there were no significant interactions between coffee extract supplementation and habitual flavanol consumption. Post hoc analyses showed no significant effect of coffee extract supplementation on cognitive function scores.
Overall, the study findings showed that daily cocoa extract supplementation did not significantly improve global or domain-specific cognitive function compared to a placebo over two years. However, a subgroup analysis showed suggestive benefits for cognitive function among those with poorer habitual diet quality at baseline. Further research is required to elucidate the e role of CE supplementation in more diverse populations and those with lower diet quality. The present study findings align with the primary results of two COSMOS cognitive ancillary randomized controlled trials, i.e., COSMOS-Web and COSMOS-Mind.
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