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 nM/L; 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.