A systematic review and meta-analysis were carried out to study the effects of low-carbohydrate diet (LCD) on weight loss and cardiovascular risk factors (search performed on PubMed, Cochrane Central Register of Controlled Trials and Scopus databases). A total of 23 reports, corresponding to 17 clinical investigations, were identified as meeting the pre-specified criteria. Meta-analysis carried out on data obtained in 1,141 obese patients, showed the LCD to be associated with significant decreases in body weight (- kg [95% CI -/-]), body mass index (- kg m(-2) [95% CI -/-]), abdominal circumference (- cm [95% CI -/-]), systolic blood pressure (- mm Hg [95% CI -/-]), diastolic blood pressure (- mm Hg [95% CI -/-]), plasma triglycerides (- mg dL(-1) [95% CI -/-]), fasting plasma glucose (- mg dL(-1) [95% CI -/-]), glycated haemoglobin (-% [95% CI -/-]), plasma insulin (- micro IU mL(-1) [95% CI -/-]) and plasma C-reactive protein, as well as an increase in high-density lipoprotein cholesterol ( mg dL(-1) [95%CI /]). Low-density lipoprotein cholesterol and creatinine did not change significantly, whereas limited data exist concerning plasma uric acid. LCD was shown to have favourable effects on body weight and major cardiovascular risk factors; however the effects on long-term health are unknown.
Hyperglycemia is associated with increased risk of cardiovascular disease. Nevertheless, results of large clinical trials suggest that tight glucose control does not reduce the risk of macrovascular cardiovascular events in type 2 diabetes mellitus and may cause harm. This may reflect the adverse consequences of increased hypoglycemia or the adverse effects of many antidiabetic agents on weight gain. The consequences of intensive therapy may also depend on the mechanism of the antidiabetic agent(s) used to achieve tight control. Metformin, an antidiabetic agent that reduces weight and activates AMP-activated protein kinase, reduces risk of cardiovascular events in overweight diabetics. In contrast, the thiazolidinedione rosiglitazone increases cardiovascular risk. Sulfonylureas may increase the risk of cardiovascular events through effects on the SUR1 of the cardiac K(ATP) channel. Stable analogues of glucagon-like peptide-1 reduce body weight and blood pressure, and have favorable effects on ischemia following reperfusion in animal models. The dipeptidyl peptidase IV inhibitors prevent the breakdown of glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide, but also decrease the degradation of several vasoactive peptides. Dipeptidyl peptidase IV inhibitors have favorable effects in animal models of ischemia/reperfusion. They have been reported both to decrease and to increase blood pressure. Clinical trials will address the effect of the incretin-based agents on macrovascular cardiovascular events.