A systematic review and meta-analysis of the omega-3 fatty acids effects on brain-derived neurotrophic factor (BDNF)

Background: Omega-3 fatty acids (omega-3 FAs) have attracted the attention of researchers
because of their influence on circulatory levels of brain-derived neurotrophic factor (BDNF). Our
objective was to review systematically and Meta-analyze randomized controlled trials (RCTs) to
assess the effects of omega-3 FAs supplementation on serum BDNF concentration.
Methods: Scopus, PubMed, Web of Science, and Cochrane Library were systematically
searched until April 2023. The Cochrane risk of bias assessment tool was utilized to evaluate
the quality of the studies. A random-effects model was employed to estimate the overall effect
size of BDNF levels, using the Standard Mean Difference (SMD) and a 95% confidence interval
(CI). The heterogeneity among the studies was assessed using chi-squared and I2 statistics.
Results: A total of 12 studies involving 587 subjects were included. The supplementation of
PUFA was found to be associated with a significant increase in serum levels of BNDF in the
group receiving the supplements, as compared to the placebo group (SMD: 0.72 pg/mL, 95%
CI: 0.28, 1.15; P < 0.001) (I2 = 84.39%, P < 0.001). Sub-group analyses revealed similar
findings in trials with fewer than 10 weeks, which utilized both animal (fish oil) and herbal
(flaxseed) forms of omega-3 supplements with a high daily dosage of 2000mg. Conclusion: The
present systematic review and meta-analysis indicate the efficacy of omega-3 FAs in increasing
the serum concentration of BDNF. Therefore, omega-3 FAs should be prioritized as agents for
increasing BDNF in interventions.