Randomized controlled trial on the lipid-lowering effect of once-daily soya drink fortified with phytosterols in normocholesterolaemic Chinese

B. M. Cheung¹, Y. C. Cheng², Y. P. Chau², M. F. Tsoi¹, V. K. Cheng², G. K. Lee², C. L. Cheung². ¹Department of Medicine, University of Hong Kong, Hong Kong, Hong Kong, ²Department of Pharmacology and Pharmacy, University of Hong Kong, Hong Kong, Hong Kong.

Introduction: Phytosterols reduce intestinal cholesterol absorption and help to lower LDL-cholesterol (1). Many Chinese adults have lactose intolerance and cannot tolerate phytosterol added to cow’s milk. We therefore conducted a randomized double-blind controlled trial to assess the efficacy and tolerability of a phytosterol-fortified soya drink in lowering serum LDL-cholesterol.

Method: Two hundred and one normocholesterolaemic healthy adult participants (100 men and 101 women; age 19-79) were randomized to daily intake for three weeks of one pack of phytosterols-enriched soya drink that contained 2 g phytosterols per day (N=100) or a matched soya drink without phytosterols (N=101). The primary outcome variable was the serum LDL-cholesterol. Adverse events, withdrawal and compliance were documented. The study protocol received ethical approval and was registered (ClinicalTrials.gov identifier: NCT02881658; Date of registration: 14 Aug 2016). All participants gave written informed consent. Data management and intention-to-treat analysis were carried out by an accredited Clinical Trials Centre and an independent statistician respectively. The change in serum LDL-cholesterol level between baseline and week 3 was the primary outcome variable analyzed. ANCOVA was used to evaluate the least square mean differences and % changes, with baseline LDL-cholesterol as a covariate. Changes in body weight, waist circumference, blood pressure, glucose and lipids were evaluated as secondary outcome variables.

Results: Only seven participants did not complete the study. The compliance (mean±SD) was 99.6±6.9% and 99.2±6.3% in the treatment and control group respectively. Serum cholesterol decreased by 6.6%, from 2.91±0.96 to 2.71±0.83 mmol/L (mean±SD), in the treatment group; and by 1.6%, from 2.83±0.81 to 2.75±0.79 mmol/L, in the control group. Compared to control, phytosterols reduced serum LDL-cholesterol (mean±SE) by 0.13±0.06 mmol/L (p=0.02). There were no significant changes in body weight, waist circumference, blood pressure, blood glucose or other lipid parameters such as HDL and triglycerides. 95% of the participants randomised to the fortified drink reported no adverse events at all. Of the six adverse events, five were intestinal symptoms. There were no serious adverse events.

Conclusion: The phytosterol-fortified soya drink reduced LDL-cholesterol and was well-tolerated. Replacing the usual soya drink with a phytosterol-fortified soya drink in Chinese may be a feasible cost-neutral means of lowering LDL-cholesterol in this massive population with rising incidence of coronary heart disease.

Reference:

1. Cheung CL et al. (2016). Sci Rep 7: 41084.