Differential effects of low-carbohydrate and low-fat diets on inflammation and endothelial function in diabetes

Objective: To characterize acute (postprandial) and chronic (after a 6-month period of weight loss) effects of a low-carbohydrate vs. a low-fat diet on subclinical markers of cardiovascular disease (CVD) in adults with type 2 diabetes. Design: At baseline and 6 months, measures of C-reactive protein (CRP), interleukin-6 (IL-6), soluble intercellular adhesion molecule (sICAM) and soluble E-selectin were obtained from archived samples (n=51) of participants randomized in a clinical trial comparing a low-carbohydrate and a low-fat diet. In a subset of participants (n=27), postprandial measures of these markers were obtained 3 h after a low-carbohydrate or low-fat liquid meal. Endothelial function was also measured by reactive hyperemic peripheral arterial tonometry during the meal test. Paired t tests and unpaired t tests compared within- and between-group changes. Results: There were no significant differences observed in postprandial measures of inflammation or endothelial function. After 6 months, CRP (mean +/- S.E.) decreased in the low-fat arm from 4.0 +/- 0.77 to 3.0 +/- 0.77 (P=.01). In the low-carbohydrate arm, sICAM decreased from 234 +/- 22 to 199 +/- 23 (P=.001), and soluble E-selectin decreased from 93 +/- 10 to 82 +/- 10 (P=.05.) A significant correlation between change in high-density lipoprotein and change in soluble E-selectin (r=-0.33, P=.04) and with the change in ICAM (r=-0.43, P=.01) was observed. Conclusions: Low-carbohydrate and low-fat diets both have beneficial effects on CVD markers. There may be different mechanisms through which weight loss with these diets potentially reduces CVD risk. (C) 2011 Elsevier Inc. All rights reserved.