Effect of phytosterols and inulin-enriched soymilk on LDL-cholesterol in Thai subjects: a double-blinded randomized controlled trial

BACKGROUND: Hypercholesterolemia, particularly high LDL-c and non-HDL-c levels, is a traditional risk for cardiovascular disease. Ingestion of diets containing phytosterols and inulin can reduce plasma LDL-c and triglyceride levels, respectively. Phytosterols and inulin-enriched soymilk may be an alternative for a supplemental diet to improve both LDL-c and non-HDL-c to reduce the risk of cardiovascular disease. METHODS: Two hundred and forty subjects who were 18 years old or older and had a baseline LDL-c of 130 mg/dl or higher were enrolled into the double-blinded randomized controlled trial study. Subjects were randomly assigned into the study group that received 2 g/day of phytosterols and 10 g/day of inulin-enriched soymilk or into the control group that received standard soymilk. The lipid profile was measured every 2 weeks for 8 weeks. Primary outcomes were 1) to determine the LDL-c reduction after consumption of phytosterols and inulin-enriched soymilk for 8 weeks and 2) to compare the difference of the LDL-c levels between the study and control groups. The secondary outcomes were to compare the difference of TC, TG and HDL-c between the study and control groups. RESULTS: At the end of the study, the median LDL-c levels decreased significantly from 165 (132, 254) mg/dl to 150 (105, 263) mg/dl in the study group (p < 0.001) and from 165 (130, 243) mg/dl to 159 (89, 277) mg/dl in the control group (p = 0.014). The LDL-c reduction was significantly better in the study group (−10.03 %, (−37.07, 36.00) vs −1.31 % (−53.40, 89.73), p < 0.001). TC also reduced significantly by 6.60 % in the study group while it reduced only by 1.76 % in the control group (p < 0.001). There were no statistical differences in TG and HDL-c levels between both study groups. The adverse events in the study group and the control groups were not different (RR 1.33 [0.871-2.030, 95 % CI]). CONCLUSION: Daily consumption of soymilk containing 2 g of phytosterols and 10 g of inulin reduced TC and LDL-c better than standard soymilk. It had no effect on TG and HDL-c levels compared to standard soymilk. Both soymilk products were comparably safe. TRIAL REGISTRATION: Thai Clinical Trial Registry: TCTR20150417001 date: April 17, 2015 ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12944-015-0149-4) contains supplementary material, which is available to authorized users.