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

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.

METHODS

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/m(2)) 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.