The burden of diabetes is rapidly increasing in line with the growing obesity epidemic. Identification of simple and easily scalable interventions is therefore urgently needed. Carnosine (beta-alanyl-L-histidine), a dipeptide with anti-inflammatory, anti-oxidative, and anti-glycating properties, has been proposed as a potential strategy for the prevention of diabetes. However, previous studies examining the effects of carnosine on cardiometabolic risk factors have produced inconsistent results. Here, we present the first systematic review and meta-analysis examining the effects of carnosine supplementation on cardiometabolic risk factors. Electronic databases including Medline, CINAHL, EMBASE and EBM Reviews were searched to identify all randomized controlled trials (RCTs) comparing supplementation with carnosine vs. placebo, usual care or other interventions. In meta-analyses of five trials with 309 participants, carnosine-supplemented groups had lower HbA1c (mean difference (MD) [95% CI]= -0.5% [-0.4,-0.6], p<0.001); fasting glucose (MD [95% CI]= -0.6 mmol/L [-1.1, -0.1], p=0.03); postprandial glucose (MD [95% CI]= -1.0 mmol/L [-1.4, -0.6], p<0.001); triglycerides (MD [95% CI]= -0.4 mmol/L [-0.6, -0.3], p=0.005); and high-sensitivity C-reactive protein (MD [95% CI]= -0.4 mg/L [-0.6, -0.2], p<0.001) compared with placebo. Low statistical heterogeneity was observed for all outcomes (I2=0-1%) except fasting glucose (I2=84%). However, heterogeneity in study design was an important limitation, including the different populations studied, and the use of varying doses of carnosine and mixed supplementation. Nevertheless, our findings suggest that carnosine may improve cardiometabolic risk factors and further well designed randomized controlled trials are needed to confirm these findings.
K. Aravind Menon: None. A. Mousa: None. B. de Courten: None.