The reduction of brain-derived neurotrophic factor (BDNF) affects cognitive function, learning, and memory and also causes behavioral disorders. Several randomized controlled trials have examined the neuroprotective effects of curcumin and its ability to increase BDNF levels, with inconclusive results. The aim of this systematic review was to evaluate the impact of curcumin supplementation on serum BDNF levels. A systematic review of the literature was conducted using PubMed, Scopus, ISI Web of Science, Cochrane library, and Google scholar to identify eligible studies up to January 2019. The studies included were randomized control trials of curcumin supplementation that reported the serum BDNF level as a primary outcome. A dose-response meta-analysis of eligible studies was performed using the random-effects model to estimate pooled effect size. Four randomized control trials with 139 participants were included. Curcumin supplementation dose and duration ranged from 200 to 1820 mg/d and 8 to 12 weeks, respectively. Curcumin supplementation significantly increased serum BDNF levels (weighted mean difference: 1789.38 pg/mL, 95% confidence interval: 722.04-2856.71, P < .01) with significant heterogeneity among the studies (I2 = 83.5%, P < .001). Subgroup analysis showed that sex, mean age of participants, curcumin dosage, and trial duration were potential sources of heterogeneity. The significant positive impact of curcumin supplementation on BDNF levels indicates its potential use for neurological disorders that are associated with low BDNF levels.
Keywords: Brain-derived neurotrophic factor; Curcumin; Meta-analysis; Systematic review; Turmeric.
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