Do omega-3 fatty acids increase BDNF levels? Original paper

In this meta-analysis of randomized controlled trials, supplementation with omega-3 fatty acids elevated serum levels of brain-derived neurotrophic factor.

The effect of omega-3 fatty acids on levels of brain-derived neurotrophic factor (BDNF).

A total of 587 participants (average ages of 22–71), including adults with coronary artery disease, type 2 diabetes, depression, schizophrenia, those at risk for posttraumatic stress disorder (PTSD), and children/adolescents with attention deficit hyperactivity disorder (ADHD).

A meta-analysis of 12 randomized controlled studies was conducted. The studies were conducted in Iran (6 studies) and in the Netherlands, Japan, Poland, Germany, Taiwan, and the Czech Republic (1 study each).

The interventions were 4 to 26 weeks in duration. The dose of omega-3 fatty acids ranged from 230 to 3,750 mg per day from fish oil or flaxseed oil.

Compared to placebo/no intervention, omega-3 fatty acids increased serum BDNF.

In subgroup analyses, omega-3 supplementation increased BDNF more effectively in trials less than 10 weeks in duration (4 studies), in participants without diagnosed psychological disorders (8 studies), when a dose greater than 2,000 mg/day was used (7 studies), in adults aged 20–30 (4 studies) compared to younger/older age groups, and in men/mixed gender populations (4 and 6 studies, respectively).

Overall, 6 studies were rated as having a low risk of bias, 5 studies as having some concerns, and 1 study as having a high risk of bias.

The mean increase in BDNF observed in this meta-analysis was 0.73 pg/mL, and though the clinical relevance of this increase is unknown; for comparison, exercise has been shown to increase BDNF levels by an average of 1.6–3.2 pg/mL.^[1] Furthermore, there was a high degree of heterogeneity in the results; therefore, the findings should be interpreted with caution.