Flaxseed Supplementation Reduces Plasma Lipoprotein(a) Levels: A Meta-Analysis

Context . Elevated levels of lipoprotein (a) [Lp(a)] are an independent risk factor for premature cardiovascular disease (CVD). Flaxseed (Linum usitiatissimum L.) is a rich source of alpha-linolenic acid, phytoestrogens, and lignans and has been shown to improve several cardiovascular risk factors, although the overall effect on Lp(a) is unknown. Objective . The study intended to assess the impact of flaxseed on plasma Lp(a) levels through a meta-analysis of the results of randomized controlled trials (RCTs). Design . PubMed-Medline, Scopus, Embase, and Google Scholar databases were searched using the following search terms in titles and abstracts: flaxseed OR Linum usitatissimum OR lignin OR linseed AND lipoprotein(a) OR lipoprotein (a) OR Lp(a) OR Lp (a). Results . Of the 48 RCTs, 6 were eligible for inclusion, and the results suggested a significant decrease in plasma Lp( a) levels-standardized mean difference: -0.22, 95% confidence interval: -0.41 to -0.04, P =.017-following supplementation with flaxseed-containing products. Conclusions . This finding highlights the potential clinical significance of flaxseed supplementation for patients who are at risk of a high residual CVD despite intensive statin therapy, patients with hyperliporoteinemia(a), and patients who prefer natural remedies for CVD prevention in the context of a healthy lifestyle. Further RCTs are needed to establish the role of flaxseed-containing products on lowering Lp(a).

Automated summary

The meta-analysis of randomized controlled trials showed that supplementation with flaxseed-containing products can significantly decrease plasma Lp(a) levels, indicating the potential clinical significance of flaxseed supplementation for high residual CVD risk patients, hyperliporoteinemia(a) patients, and those who prefer natural remedies for CVD prevention. Further RCTs are needed to confirm the role of flaxseed-containing products in lowering Lp(a).