A combined DHA-rich fish oil and cocoa flavanols intervention does not improve cognition or brain structure in older adults with memory complaints: Results from the CANN randomized, controlled parallel-design study
Am J Clin Nutr. 2023 Jun 12:S0002-9165(23)65970-2. doi: 10.1016/j.ajcnut.2023.06.008. Online ahead of print.
ABSTRACT
BACKGROUND: There is evidence that both omega-3 long-chain PUFAs (EPA and DHA) and cocoa flavanols can improve cognitive performance in both healthy individuals and in those with memory complaints. However, their combined effect is unknown.
OBJECTIVE: To investigate the combined effect of EPA/DHA and cocoa flavanols (OM3FLAV) on cognitive performance and brain structures in older adults with memory complaints.
METHODS: A randomized placebo-controlled trial of DHA-rich fish oil (providing 1.1 g/d DHA and 0.4 g/d EPA) and a flavanol-rich dark chocolate (providing 500 mg/d flavan-3-ols) was conducted in 259 older adults with either Subjective Cognitive Impairment (SCI) or Mild Cognitive Impairment (MCI). Participants underwent assessment at baseline, 3 and 12 months. The primary outcome was number of false positives on a picture recognition task from the Cognitive Drug Research (CDR) computerized assessment battery. Secondary outcomes included other cognition and mood outcomes, plasma lipids, brain derived neurotrophic factor (BDNF) and glucose levels. A subset of 110 participants underwent structural neuroimaging at baseline and at 12-months.
RESULTS: 197 participants completed the study. The combined intervention had no significant effect on any cognitive outcomes, with the exception of reaction time variability (p=0.007), alertness (p<0.001) and executive function (p<0.001), with a decline in function observed in the OM3FLAV group (118.6 (25.3) at baseline versus 113.3 (25.4) at 12m for executive function) relative to the control, and an associated decrease in cortical volume (p=0.039). Compared with the control group, OM3FLAV increased plasma HDL-cholesterol, total-cholesterol ratio (p<0.001) and glucose (p=0.008) and reduced TG concentrations (p<0.001) by 3m which were sustained to 12m, with no effect on BDNF. Changes in plasma EPA and DHA and urinary flavonoid metabolite concentrations confirmed compliance to the intervention.
CONCLUSIONS: These results suggest that co-supplementation with omega-3 PUFA and cocoa flavanols for 12 months does not improve cognitive outcomes in those with cognitive impairment. The trial was registered on Clinicaltrials.gov (NCT02525198).
PMID:37315924 | DOI:10.1016/j.ajcnut.2023.06.008