Soy in hypercholesterolaemia: a double-blind, placebo-controlled trial

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.

Randomised, placebo-controlled, double-blind, parallel group, single centre study.

Primary care in Joensuu, North Karelia, Finland.

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 Eight subjects were withdrawn, six from the active group, two from the placebo group.

The preparations were given as two daily liquid supplements in addition to the subjects' regular diets for 6 weeks.

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.

Added to a regular diet, Abacor significantly reduced LDL-cholesterol and total cholesterol. These beneficial effects occurred within 6 weeks of treatment.