Soy in hypercholesterolaemia: a double-blind, placebo-control led trial

Objective: To study whether Abacor(R), 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(R) 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 Eight subjects were withdrawn, six from the active group, two from the placebo group.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(R) 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% Cl 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% Cl 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(R) 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(R) significantly reduced LDL-cholesterol and total cholesterol. These beneficial effects occurred within 6 weeks of treatment. Sponsorship: Commercial organisation.