Fruit and vegetable intakes, C-reactive protein, and the metabolic syndrome

Abstract

Background: Limited data on the relation between the risk of the metabolic syndrome and fruit and vegetable intakes and inflammatory marker concentrations are available. Objective: We evaluated the relation between fruit and vegetable intakes and C-reactive protein (CRP) concentrations and the prevalence of the metabolic syndrome. Design: Fruit and vegetable intakes were assessed with the use of a validated semiquantitative food-frequency questionnaire in a cross-sectional study of 486 Tehrani female teachers aged 40-60 y. Anthropometric measurements were made and blood pressure was assessed according to standard methods. Fasting blood samples were taken for biochemical measurements. The metabolic syndrome was defined on the basis of the National Cholesterol Education Program Adult Treatment Panel III guidelines. Results: The reported mean daily fruit and vegetable intakes were 228 ± 79 and 186 ± 88 g/d, respectively. Both fruit and vegetable intakes were inversely associated with plasma CRP concentrations. After statistical control for age, body mass index, and waist circumference, mean plasma CRP concentrations across increasing quintile categories of fruit intakes were 1.94, 1.79, 1.65, 1.61, and 1.56 mg/L and of vegetable intakes were 2.03, 1.82, 1.58, 1.52, and 1.47 mg/L (P for trend < 0.01 for both). These inverse associations remained significant after additional control for other potential confounding variables and dietary factors. After control for potential confounders, persons in the highest quintile of fruit intake had a 34% (95% CI: 20%, 46%) lower and those in the highest quintile of vegetables intake had a 30% (95% CI: 16%, 39%) lower chance of having the metabolic syndrome than did those in the lowest quintiles. Conclusions: Higher intakes of fruit and vegetables are associated with a lower risk of the metabolic syndrome; the lower risk may be the result of lower CRP concentrations. These findings support current dietary recommendations to increase daily intakes of fruit and vegetables as a primary preventive measure against cardiovascular disease. © 2006 American Society for Nutrition.