Comparison between the effects of soy milk and non-fat cow milk on lipid profile and lipid peroxidation in patients with primary hypercholesterolemia

OBJECTIVE: This study assessed whether the consumption of soy milk could add significantly to the lipid profile and lipid peroxidation in comparison with non-fat milk. METHODS: A double-blind, randomized, crossover study was conducted on 60 outpatients with primary hypercholesterolemia following a lipid-lowering diet for at least 6 wk. Lipid profile was obtained at baseline and, at 6 and 12 wk, with the patients randomly assigned to receive initially 1 L/d of soy milk or non-fat cow milk for 6 wk. Lipid peroxidation was estimated by plasma thiobarbituric reactive substances. Apolipoprotein E genotypes were examined by polymerase chain reaction restriction fragment length polymorphism. RESULTS: The soy milk diet was associated with low-density lipoprotein cholesterol reduction (baseline = 157 +/- 5 mg/dL; soy milk = 148 +/- 4 mg/dL; non-fat cow milk = 158 +/- 4 mg/dL; P < 0.05, soy milk versus other treatments) and with high-density lipoprotein cholesterol increase (baseline = 58 +/- 2 mg/dL; soy milk = 62 2 mg/dL; non-fat cow milk = 57 +/- 2 mg/dL; P < 0.05, soy milk versus other treatments). In addition, plasma thiobarbituric reactive substances were reduced by the soy milk diet (baseline = 1.82 +/- 0.12 nMIL; soy milk = 1.49 +/- 0.09 nM/L; non-fat cow milk = 1.91 +/- 0.11 nM/mL; P < 0.05, soy milk versus non-fat cow milk). Changes in lipid profile were not influenced by APOE genotypes. CONCLUSIONS: These results indicate that soy milk as part of a lipid-lowering diet has beneficial effects in improving lipid profile and reducing lipid peroxidation.