Estimated daily quercetin intake and association with the prevalence of type 2 diabetes mellitus in Chinese adults.

PURPOSE: Quercetin is one of potential antidiabetic substances because of its powerful antioxidant and anti-inflammatory actions. The purpose of this study is to estimate daily quercetin intake and assess the relationship between dietary quercetin intake and the prevalence of type 2 diabetes mellitus (T2DM) in a Chinese population.

METHODS: Dietary intake was investigated by a validated 100-item food frequency questionnaire. Daily intakes of quercetin and nutrients were calculated accordingly. T2DM was diagnosed based on the criteria of the American Diabetes Association. Adjusted logistic regression models were used to analyze the relationship between the quartiles of quercetin intake and the prevalence of T2DM.

RESULTS: The prevalences of T2DM were 8.35% in men and 4.68% in women. The main food sources of quercetin were apple, orange, and green tea. Daily intake of quercetin was 20.9 ± 2.32 mg/day (mean ± SD). After adjusting for potentially confounding factors, the odds ratios (95% CI) for T2DM across the ascending quartiles of quercetin intake were: 1.00 (reference), 0.75 (0.60-0.95), 0.76 (0.59-0.99), and 0.63 (0.51-0.94).

CONCLUSIONS: The results of the present study showed that quercetin intake was inversely related to the prevalence of T2DM in the Chinese population, suggesting a protective effect of quercetin in the development of T2DM.