Plain language summary
A growing body of evidence suggests that some modifiable factors, including cardiometabolic disorders such as hypertension, diabetes and hypercholesterolemia, as well as lifestyle factors such as physical exercise and diet, are associated with an increased risk of developing dementia. Anthocyanins, a flavonoid subclass found in dark berries and fruits, are among the dietary factors that may have positive effects on the pathogenesis of Alzheimer’s disease. The aim of this study was to assess whether anthocyanins can improve cognition and reduce the risk of dementia. This study is a 24-week randomised, double-blind, placebo-controlled Phase II study. Two-hundred and six participants were randomly assigned to one of the two groups: anthocyanins (n=106) or placebo (n=100). Results show that there wasn’t any significant group difference at the end of the study (24 weeks) in episodic memory (primary analysis) or for the secondary cognitive outcomes. However, there was a significant difference in slopes during weeks 8−24 where the anthocyanin group improved while the placebo group worsened. Furthermore, anthocyanin capsules were well-tolerated and safe to use. Authors conclude that future studies need to explore the potential mechanisms leading to cognitive improvement, how they relate to bioavailability of anthocyanins and metabolites, the optimal dosage, and the duration of treatment.
Abstract
IMPORTANCE Identifying nutritional compounds which can reduce cognitive decline in older people is a hugely important topic. OBJECTIVE To study the safety and effect of anthocyanins in maintaining cognitive functioning in people at increased risk for dementia. DESIGN, SETTING, AND PARTICIPANTS Participants (206 individuals, aged 60-80 years) diagnosed with either mild cognitive impairment (MCI) or two or more cardiometabolic disorders (i.e., diabetes, hypertension, obesity) were enrolled at three different centres in Norway. INTERVENTION Participants were randomly assigned to four capsules with a total of 320 mg/d of naturally purified anthocyanins or placebo 1:1 for 24 weeks. MAIN OUTCOMES AND MEASURES The primary outcome was the Quality of Episodic Memory composite measure (0-100) from an online cognitive test battery CogTrack, which was administered at baseline and monthly for the next 24 weeks. Secondary outcomes included other cognitive scores from the CogTrack battery. We applied mixed effects models with a baseline test score, group, time and their interaction as fixed effects, as well as other predefined baseline covariates. The primary comparison was the group difference at week 24 based on a modified intention-to-treat principle. RESULTS The primary analysis did not show a significant group difference at 24 weeks (78.2 versus 76.8; adjusted mean difference 1.4 (95% confidence interval -0.9-3.7); effect size 0.15; p = 0.23). However, there was a significant difference in slopes during weeks 8-24 (p = 0.007); the anthocyanin group improved while the placebo group worsened. No differences were found for the secondary cognitive outcomes. Anthocyanin capsules were well-tolerated and safe to use. CONCLUSION Anthocyanin supplementation for 24 weeks was safe and well tolerated in people with MCI or cardiometabolic disorders. We found no significant group difference in episodic memory at the end of the study but statistically significant differences in slopes. Further studies are warranted to explore whether anthocyanins supplementation can reduce cognitive decline in people at increased risk of dementia. TRIAL REGISTRATION ClinicalTrials.gov, (Identifier NCT03419039). http://www. CLINICALTRIALS gov/, NCT03419039.
Methodological quality
Jadad score
:
5
Allocation concealment
:
Yes
