Whole and refined grain intakes are related to inflammatory protein concentrations in human plasma

Inflammation may play a role in the pathogenesis of cardiovascular disease and type 2 diabetes, and it has been suggested that the protective effects of whole-grain consumption could be mediated by an effect on inflammation, although few studies have examined the relationships between grain intakes and inflammatory protein concentrations. Our objectives in this study were to examine the associations of whole grain and refined grain intake with plasminogen activator inhibitor type 1 (PAI-1), C-reactive protein (CRP), and fibrinogen plasma concentrations. Cross-sectional data from the Insulin Resistance Atherosclerosis Study were used to perform multiple regression analyses using dietary information on whole and refined grain intakes from a FFQ and clinical measures of plasma inflammatory protein concentrations in participants free of type 2 diabetes. After adjustment for demographic, lifestyle, and dietary variables, whole-grain intake was inversely related to log PAI-1 (beta = -0.102; SEM = 0.038; P = 0.0077) and log CRP (beta = -0.102; SEM = 0.048; P = 0.0340). Adding insulin sensitivity, waist circumference, and 2-h postload glucose to the model attenuated both associations to nonsignificance. Refined grain was positively related to log PAI-1 in the multivariate model (beta = 0.076; SEM = 0.034; P = 0.0251) and the relationship remained unchanged by additional adjustment for metabolic variables. Fibrinogen concentrations were not related to whole or refined grain intake. In summary, whole grain intake was inversely related to PAI-1 and CRP plasma concentrations, but these relationships were attenuated by the addition of metabolic variables to the model. Refined grain intake was positively independently related to plasma PAI-1 concentrations.