This cross-sectional study was conducted on a cohort of 53,711 Chinese adults of Shanghai and evaluated their soy isoflavones (SI) intake. The dietary intake of SI ranged from 0.8 to 78.0 mg/day (median: 13.5 mg/day; IQR: 7.7, 21.4 mg/day).

Results indicate that the prevalence of overweight/obesity and central obesity decreased with increasing tertiles (p for trend < 0.001), with the highest tertile group having a lower prevalence of obesity (12.0% vs. 13.4%, p < 0.001) and central obesity (29.3% vs. 31.1%, p < 0.001) relative to the lowest group. The odds ratio (OR) for overall obesity was 0.91 (95% CI: 0.85, 0.98) in the highest versus the lowest SI tertile group. The associations differed by sex (p for interaction < 0.05), with the OR (95%CI) for the highest versus the lowest tertile groups being 0.89 (0.79, 0.99) in men and 0.91 (0.82, 1.00) in women. The negative association was observed in postmenopausal women (OR: 0.86; 95% CI: 0.77, 0.96) but not in premenopausal women (OR: 1.12; 95%CI: 0.90, 1.39). A negative association was also observed between SI intake and central obesity, and a significant modifying effect of sex was found on the association. No significant interactions were observed between SI intake and physical activity levels.

In conclusion, Chinese adults with higher dietary intake of SI may be less likely to be obese, particularly for postmenopausal women.

Zhu J, Zhao Q, Qiu Y, et al. Soy Isoflavones Intake and Obesity in Chinese Adults: A Cross-Sectional Study in Shanghai, China. Nutrients. 2021;13(8):2715. Published 2021 Aug 6. doi:10.3390/nu13082715

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