Low-carbohydrate diets (LCD) are increasing in popularity, but their effect on vascular health has been questioned. Endothelial microvesicles (EMV) are membrane-derived vesicles with the potential to act as a sensitive prognostic biomarker of vascular health and endothelial function. The aim of this study was to examine the influence of a LCD on EMV and other endothelial biomarkers of protein origin. Twenty-four overweight women (age, 48.4 ± 0.6 years; height, 1.60 ± 0.07 m; body mass, 76.5 ± 9.1 kg; body mass index, 28.1 ± 2.7 kg·m−2; waist circumference, 84.1 ± 7.4 cm; mean ± standard deviation) were randomised to either 24 weeks on their normal diet (ND) or a LCD, after which they crossed over to 24 weeks on the alternative diet. Participants were assisted in reducing carbohydrate intake, but not below 40 g·day−1. Body composition and endothelial biomarkers were assessed at the crossover point and at the end of the study. Daily carbohydrate intake (87 ± 7 versus 179 ± 11 g) and the percentage of energy derived from carbohydrate (29% versus 44%) were lower (p < 0.05) on the LCD compared to the ND, but absolute fat and saturated fat intake were unchanged. Body mass and waist circumference were 3.7 ± 0.8 kg and 3.5 ± 1.0 cm lower (p < 0.05), respectively, after the LCD compared with the ND phases. CD31+CD41−EMV, soluble (s) thrombomodulin, sE-selectin, sP-selectin, serum amyloid A and C-reactive protein were lower (p < 0.05) after the LCD compared to the ND, but serum lipids and apolipoproteins were not different. EMV along with a range of endothelial and inflammatory biomarkers are reduced by a LCD that involves modest weight loss.

In an Australian study of 1200 subjects 17 % had tried or intended to try a low-carbohydrate diet, and 70 % believed they should cut back on carbohydrates to lose weight (1) . With increasing levels of obesity, the low-carbohydrate diet has become popular as a weight loss method. While weight loss through consumption of a low carbohydrate diet has been proven (2) there is contradictory evidence regarding its effect on bone health (3,4) . Furthermore the effect of this diet on bone health for greater than 12 weeks is unknown. The aim of this study was to assess the effect of a low-carbohydrate diet consumed over 24 weeks on biomarkers of bone health in pre-and postmenopausal females.Following ethical approval and informed consent subjects were screened. 24 females (13 pre-menopausal; 11 postmenopausal) were randomly assigned to a control (AB) or low-carbohydrate diet (BA) group for 24 weeks. Subjects were then crossed over to the alternative dietary regimen for 24 weeks. Blood and urine samples taken at week 24 and 48 were analysed for biomarkers of bone resorption and formation using ELIZA. Urine pH was measured and a 3 day food diary analysed using CompEat 2 . Data was analysed for treatment and carryover effects using unpaired t-tests. Non-parametric tests were used where data was not normally distributed.