Associations of dietary flavonoids with risk of type 2 diabetes, and markers of insulin resistance and systemic inflammation in women: a prospective study and cross-sectional analysis

J Am Coll Nutr. 2005 Oct;24(5):376-84. doi: 10.1080/07315724.2005.10719488.


Objective: Flavonoids, as antioxidants, may prevent the progressive impairment of pancreatic beta-cell function due to oxidative stress and may thus reduce the occurrence of type 2 diabetes. The aim of the present study was to examine the association of dietary flavonol and flavone intake with type 2 diabetes, and biomarkers of insulin resistance and systemic inflammation.

Methods: In 38,018 women aged > or =45 y and free of cardiovascular disease, cancer and diabetes with an average 8.8 y of follow-up, we calculated relative risks (RRs) of incident type 2 diabetes (1,614 events) according to dietary intake of total or individual flavonols and flavones and flavonoid-rich foods. We also measured and examined plasma concentrations of insulin, HbA(1C), CRP, and IL-6 in relation to total flavonol and flavone intake among 344 nondiabetic women.

Results: During 332,905 person-years of follow-up, none of total flavonols and flavones, quercetin, kaempferol, myricetin, apigenin, and luteolin was significantly associated with risk of type 2 diabetes. Among flavonoid-rich foods, apple and tea consumption was associated with diabetes risk. Women consuming > or =1 apple/d showed a significant 28% reduced risk of type 2 diabetes compared with those who consumed no apples (the multivariate-adjusted RR = 0.72, 95% CI: 0.56, 0.92; p = 0.006 for trend). Tea consumption was also inversely associated with diabetes risk but with a borderline significant trend (> or =4 cups/d vs. none: RR 0.73, 95% CI: 0.52-1.01; p for trend = 0.06). In 344 nondiabetic women, total intake of flavonols and flavones was not significantly related to plasma concentrations of fasting insulin, HbA(1C), CRP, or IL-6.

Conclusions: These results do not support the hypothesis that high intake of flavonols and flavones reduces the development of type 2 diabetes, although we cannot rule out a modest inverse association with intake of apples and tea.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Biomarkers / analysis
  • Cohort Studies
  • Cross-Sectional Studies
  • Diabetes Mellitus, Type 2 / epidemiology*
  • Diabetes Mellitus, Type 2 / etiology
  • Diabetes Mellitus, Type 2 / metabolism
  • Diet*
  • Female
  • Flavonoids / administration & dosage
  • Flavonoids / metabolism
  • Flavonoids / pharmacology*
  • Follow-Up Studies
  • Humans
  • Inflammation* / metabolism
  • Insulin Resistance*
  • Malus
  • Middle Aged
  • Oxidative Stress / drug effects
  • Prospective Studies
  • Randomized Controlled Trials as Topic
  • Risk Factors
  • Tea


  • Biomarkers
  • Flavonoids
  • Tea