Dietary carbohydrate modification induces alterations in gene expression in abdominal subcutaneous adipose tissue in persons with the metabolic syndrome: the FUNGENUT Study

Abstract

Background: Diets rich in whole-grain cereals and foods with a low glycemic index may protect against type 2 diabetes, but the underlying molecular mechanisms are unknown.Objective: The main objective was to test whether 2 different carbohydrate modifications—a rye-pasta diet characterized by a low postprandial insulin response and an oat-wheat-potato diet characterized by a high postprandial insulin response—affect gene expression in subcutaneous adipose tissue (SAT) in persons with the metabolic syndrome.Design: We assessed the effect of carbohydrate modification on SAT gene expression in 47 subjects [24 men and 23 women with a mean (±SD) age of 55 ± 6 y] with the features of the metabolic syndrome in a parallel study design. The subjects had a mean (±SD) body mass index (kg/m2) of 32.1 ± 3.8 and a 2-h plasma glucose concentration of 8.0 ± 2.3 mmol/L. Adipose tissue biopsies were performed, and oral-glucose-tolerance tests and other biochemical measurements were conducted before and after the intervention.Results: We detected 71 down-regulated genes in the rye-pasta group, including genes linked to insulin signaling and apoptosis. In contrast, the 12-wk oat-wheat-potato diet up-regulated 62 genes related to stress, cytokine-chemokine–mediated immunity, and the interleukin pathway. The insulinogenic index improved after the rye-pasta diet (P = 0.004) but not after the oat-wheat-potato diet. Body weight was unchanged in both groups.Conclusions: Dietary carbohydrate modification with rye and pasta or oat, wheat, and potato differentially modulates the gene expression profile in abdominal subcutaneous adipose tissue, even in the absence of weight loss.