Relationship between dietary soy isoflavones and blood lipid levels in 40 - 65 year-olds in Guangzhou

Abstract

To study the relationship between dietary soy isoflavones and blood lipids among residents of 40 - 65 years old, in Guangzhou. Dietary soy isoflavones and other nutrients intakes were assessed with quantitative food frequency questionnaire (FFQ). Total cholesterol (TC), triglycerides (TG), HDL cholesterol (HDL-C) and LDL cholesterol (LDL-C) in plasma were measured with colorimetry. Ranges of dietary soy isoflavones intake among 134 males and 261 females were from 0 mg/day to 61.96 mg/day and 0 mg/day to 82.52 mg/day, with means of 11.95 mg/day, 14.90 mg/day, respectively. After adjusted for total energy intake and fat percent energy, differences of TC, LDL-C in total population and TC in women were statistically significant between groups (P value was 0.002, 0.008, 0.004, respectively) and dose-effect relationships (P value was < 0.001, 0.012, 0.001, respectively) were observed between dietary soy isoflavones intake and the upper mentioned three indices. Compared with the low-intake group, these three indices lowered 7.06%, 10.13% and 7.48%, respectively in high-intake group. Critical significance of LDL-C was observed both in women and men between groups. Further controlled for age, BMI and WHR, no obvious change of the results was observed. Moderate intakes of soy isoflavone as part of a regular diet seemed to be associated with favorable blood lipid levels.