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

Brain-derived neurotrophic factor (BDNF) is a protein produced inside nerve cells. It is important
to a healthy brain because it promotes the survival of nerve cells by playing a role in the growth,
maturation, and maintenance of these cells. BDNF is also involved in plastic changes related to
learning and memory. It regulates the structure, function, and development of the neurons and
synapses that form your brain’s internal communication network. 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.