DHA supplementation improves cognitive function via enhancing Aβ-mediated autophagy in Chinese elderly with mild cognitive impairment: a randomised placebo-controlled trial.
Level 2 - randomized trial
Randomized, double-blind, placebo-controlled trial
PubMed 29142143 · doi:10.1136/jnnp-2017-316176
What was done
A randomized, double-blind, placebo-controlled trial in Tianjin, China evaluated 240 elderly individuals with mild cognitive impairment assigned to either docosahexaenoic acid (DHA 2 g/day, n=120) or corn oil placebo (n=120) for 24 months. Cognitive performance and blood biomarkers related to amyloid beta (Aβ) and autophagy were measured at baseline, 6, 12, 18, and 24 months, with data analyzed using generalized estimating equations.
What was found
A total of 217 participants completed the trial (109 DHA, 108 placebo). Scores for full-scale IQ, verbal IQ, and subdomains of information and digit span were significantly higher in the DHA group than in controls (p<0.05; no absolute scores or effect sizes reported in the abstract). In the DHA group, blood Aβ-42 level and Aβ protein precursor mRNA expression decreased (p<0.05), while Beclin-1, LC3-II levels, and LC3-II mRNA expression increased (p<0.05).
Why it matters
This trial suggests that two years of DHA supplementation may improve selected cognitive measures in mild cognitive impairment, potentially by modulating Aβ-related autophagy pathways.
Limits
The abstract reports only p-values without absolute score changes, effect sizes, or confidence intervals. The trial was conducted in a single geographic cohort in China, limiting generalizability to populations with different baseline diets or genetic profiles, and peripheral blood markers were used as proxies for central nervous system pathology.
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- supports In a 2-year trial in patients with mild cognitive impairment, 2 grams of omega-3 daily improved cognitive and executive function, lowered plasma amyloid-beta, and increased markers of neuronal autophagy compared to placebo.