Impact of flaxseed supplementation on plasma lipoprotein(a) concentrations: A systematic review and meta-analysis of randomized controlled trials.

The aim of the study was to investigate the impact of supplementation with flaxseed on plasma lipoprotein(a) [Lp(a)] levels through a systematic review and meta-analysis of eligible randomized placebo-controlled trials. PubMed, Scopus, Cochrane Library, and ISI Web of Science were searched for randomized controlled trials (RCTs) which have been published up to November 2019. RCTs that investigated the effect of flaxseed supplementation on plasma Lp(a) levels in adults were included for final analysis. The random effects model was used for calculating the overall effects. Meta-analysis of 7 selected RCTs with 629 individuals showed significant lowering effect of flaxseed supplementation on Lp(a) (MD -2.06 mg/dl; 95% CI: -3.846, -0.274, p = .024), without considerable heterogeneity between studies (p = .986, I2 = 0%). Subgroup analysis also revealed that longer duration only showed significant lowering effect of flaxseed supplementation on Lp(a). This meta-analysis has shown that flaxseed supplementation might significantly decrease plasma Lp(a) levels. Future well-designed and long-term clinical trials are required to confirm these results.