Abstract P165: The Long-term Effect of a Low-Carbohydrate Diet on Endothelial Dysfunction and Insulin Resistance: A Randomized Controlled Trial
The long-term effects of low-carbohydrate diets versus low-fat diets on endothelial dysfunction and insulin resistance are unclear.
A total of 148 study participants with a body mass index of 30 - 45 kg/m2 (Mean: 35.4 kg/m2) who were free of diabetes, cardiovascular diseases and kidney disease were recruited. The participants were randomly assigned to either a low-carbohydrate diet (<40 g/day; N=75) or a low fat (<30% energy from fat, <10% from saturated fat; N=73) diet. Two 24-hour dietary recalls were conducted at each clinic visit (0, 3, 6 and 12 months of intervention). Participants met with a study dietitian weekly for the first month followed by group settings bi-weekly for 5 months and monthly for the last 6 months. Each group was provided the same behavioral curriculum related to diet emphasizing portion control and eating habits. Biomarkers for endothelial function and insulin resistance included E-selectin, Intercellular Adhesion Molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), Insulin-like growth Factor-1 (IGF-1), serum insulin, and glucose. Mixed-effect regression models including group, time and their interaction were used to analyze the data.
Of the study participants, 60 in the low-fat group (81.1%) and 59 in the low-carbohydrate group (79.7%) completed the entire intervention. The mean age was 46.8 years, 88.5% were women and 55.1% were African-Americans. The low-carbohydrate group lost approximately 3.5 kg more body weight than did the low-fat group (P= 0.002) on average. Compared to the low-fat diet, the low-carbohydrate diet resulted in greater reductions in E-selectin (net change: -4.5, -4.3, and -3.8 ng/mL at 3, 6, and 12 months, respectively; overall P= 0.002) and ICAM-1 (net change: -7.3, -10.4, and -16.8 ng/mL at 3, 6, and 12 months, respectively; overall P= 0.06). There was no significant change in any other markers.
Our findings suggest that the low-carbohydrate is at least as effective as the low-fat diet at improving endothelial dysfunction and insulin resistance.
- © 2013 by American Heart Association, Inc.