Therapy
Soy isoflavones do not affect Lp(a) levels, a meta-analysis of 10 trials and 973 subjects (J Clin Lipidol 2018)
Original title: Effect of soy isoflavone supplementation on plasma lipoprotein(a) concentrations: A meta-analysis
This systematic review and meta-analysis pooled 10 randomised placebo-controlled trials (11 treatment arms, 973 subjects) to assess the effect of soy isoflavone supplementation on plasma Lp(a). No significant change in Lp(a) was found after soy isoflavone supplementation (standardised mean difference 0.08, 95% CI -0.05 to 0.20, P=.228), an effect robust in leave-one-out sensitivity analysis, and neither dose nor duration of supplementation was significantly associated with the effect size in meta-regression. The findings show soy isoflavone supplementation, despite its known effects on total, LDL and HDL cholesterol, has no significant effect on plasma Lp(a) concentrations.
Original abstract
Background: Soy supplementation has been shown to reduce total and low-density lipoprotein cholesterol, while increasing high-density lipoprotein cholesterol. However, contradictory effects of soy isoflavone supplementation on lipoprotein(a) [Lp(a)] have been reported suggesting the need for a meta-analysis to be undertaken.
Objective: The aim of the study was to investigate the impact of supplementation with soy isoflavones on plasma Lp(a) levels through a systematic review and meta-analysis of eligible randomized placebo-controlled trials.
Methods: The search included PubMed-Medline, Scopus, ISI Web of Knowledge, and Google Scholar databases (by March 26, 2017), and quality of studies was evaluated according to Cochrane criteria. Quantitative data synthesis was performed using a random-effects model, with standardized mean difference and 95% confidence interval as summary statistics. Meta-regression and leave-one-out sensitivity analysis were performed to assess the modifiers of treatment response.
Results: Ten eligible studies comprising 11 treatment arms with 973 subjects were selected for the meta-analysis. Meta-analysis did not suggest any significant alteration of plasma Lp(a) levels after supplementation with soy isoflavones (standardized mean difference: 0.08, 95% confidence interval: -0.05, 0.20, P = .228). The effect size was robust in the leave-one-out sensitivity analysis. In meta-regression analysis, neither dose nor duration of supplementation with soy isoflavones was significantly associated with the effect size.
Conclusion: This meta-analysis of the 10 available randomized placebo-controlled trials revealed no significant effect of soy isoflavones treatment on plasma Lp(a) concentrations.
Summary written by lp-a.org from the published abstract; figures as published. Page updated 18 August 2026. Methods.