HbA1C levels by frequency of fruit and vegetable consumption and BMI from NHANES III

Objectives Diets rich in fruits or vegetables may protect against diabetes. HbA1C is a long term marker of glycemic regulation. Because diabetes risk increases with body mass index (BMI), this study examined the potential inverse association between fruit or vegetable consumption and HbA1C levels by BMI category. Methods Data on 14,100 U.S. adults aged ≥19 y in NHANES III were analyzed. We examined HbA1C levels by tertiles of fruit and vegetable intakes within groups stratified by BMI (normal, overweight, obese) and sex/age (males‐ aged 19–65 y and pre‐ and post‐menopausal females). Fruit and vegetable intake was measured by food frequency questionnaire. We excluded diabetics (self report), subjects with extreme weight or height, and women who were pregnant, lactating or missing menopausal status. Linear regression models adjusted for serum cotinine, alcohol consumption, education, age, BMI (within categories, continuous), and linear trends were assessed for the tertiles. Results Increased frequency of fruit consumption was associated with lower HbA1C among overweight pre‐menopausal and normal weight post‐menopausal women and overweight men (trend test p < 0.05). Increased frequency of vegetable intake was associated with lower HbA1C levels among normal premenopausal women (trend test p < 0.05). Conclusions In this examination of HbA1C levels among men and women in standard BMI categories, we found an inconsistent pattern of increased fruit or vegetable intake in relation to HbA1C. However, in some subgroups, there appears to be a relationship between increased frequency of fruit or vegetable consumption and a long term marker of glycemic regulation.