Soy in hypercholesterolaemia: a double-blind, placebo-controlled trial
Objective: To study whether Abacor®, a product based on isolated soy protein with high and standardised levels of isoflavones and cotyledon soy fibres, was more effective in lowering total and LDL cholesterol than placebo.Design: Randomised, placebo-controlled, double-blind, parallel group, single centre study.Setting: Primary care in Joensuu, North Karelia, Finland.Subjects: Subjects were screened from the patient database of the health centre; 30 were randomised to the Abacor® group and 30 subjects to placebo. Eight subjects were withdrawn, six from the active group, two from the placebo group.Intervention: The preparations were given as two daily liquid supplements in addition to the subjects' regular diets for 6 weeks.Results: Abacor® showed a statistically significant lipid-lowering effect as compared to placebo, although an unexpected reduction was seen in the placebo group. The estimated difference between active treatment and placebo was 0.25 mmol/l (95% CI 0.01, 0.50; P=0.049) for total cholesterol, corresponding to reductions of 8.3 and 5.1%, respectively. The difference in reduction of LDL-cholesterol was 0.27 mmol/l (95% CI 0.06, 0.49; P=0.014) and corresponded to a reduction of 13.2% in the active treatment group, and 8.0% in the placebo group. Abacor® showed a rapid onset of effect, as compared with placebo. During a wash-out period of 4 weeks after treatment, the subjects returned to pre-treatment cholesterol levels.Conclusion: Added to a regular diet, Abacor® significantly reduced LDL-cholesterol and total cholesterol. These beneficial effects occurred within 6 weeks of treatment.Sponsorship: Commercial organisation.