Soy milk: A functional beverage with hypocholesterolemic effects? A systematic review of randomized controlled trials

Objective: Current guidelines have highlighted the role of diet in conjunction with drug therapy in the management of dyslipidemia. Over the last two decades, the effect of soy milk, a derivative of soybean, on blood lipids has been the focus of nutritional researches. The present study aimed to provide a comprehensive review of clinical trials investigating the effect of soy milk on blood lipids. Methods: An electronic database searching including PubMed, EMBASE, Scopus, and CENTRAL was performed to extract all the records that were published up to May 2018 using MeSH terms and relevant keywords. Randomized clinical trials that had evaluated the effect of soy milk consumption on serum lipids including total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were eligible for inclusion to this systematic review. Results: Eight eligible trials comprising a total of 263 subjects were included in this review. Three studies reported no significant improvement in any of the serum lipid parameters following soy milk consumption. A significant decrease in serum TG, TC, and LDL-C was reported by 1, 1 and 3 trials. Also, 1 trial found that soy milk consumption was accompanied by a significant increase in HDL-C. Conclusion: Evidence from clinical trials regarding the hypolipidemic effect of soy milk is limited and controversial. More well-designed clinical trials with large sample size and longer duration are warranted.