Greater habitual soyfood consumption is associated with decreased carotid intima–media thickness and better plasma lipids in Chinese middle-aged adults

Many clinical studies have shown high-dose supplemental soy protein has beneficial effects on cardiovascular risk factors. We examined the association between habitual soyfood intake and carotid intima–media thickness (IMT) and plasma lipids in a cross-sectional study including 406 (M 134, F 272) middle-aged Chinese adults (40–65 years) without confirmed relevant diseases. We found significantly dose-respondent decreases in bifurcation IMT, total and LDL cholesterol associated with increased usual soyfood intake after adjusting for potential confounders (p for trend, all p < 0.05). Covariate-adjusted mean bifurcation IMT, total and LDL cholesterol decreased by 9.4%, 6.2% and 10.4% in women (p = 0.020, 0.035, 0.110), 16.0%, 12.3% and 19.6% in men (p = 0.036, 0.005, 0.002), and 9.9%, 9.3% and 15.4% in total men and women combined (p = 0.010, <0.001, <0.001) when the mean intake of soy protein increased from 0.87 (F) or 0.64 (M) g/day (1st tertile) to 8.35 (F) or 7.48 (M) g/day (3rd tertile), respectively. Significant interaction between sex and soy consumption on bifurcation IMT was observed (p = 0.008). In conclusion, higher habitual soyfood consumption is associated with decreased bifurcation IMT, plasma TC and LDL-c in middle-aged Chinese adults. The association is more apparent in men than in women.