Histidine-containing dipeptides reduce central obesity and improve glycaemic outcomes: A systematic review and meta-analysis of randomized controlled trials.

Supplementation with histidine-containing dipeptides has been shown to improve obesity and glycaemic outcomes in animal and human studies. We conducted a systematic review and meta-analysis of randomized controlled trials to examine these effects. Electronic databases were searched investigating the effects of histidine-containing dipeptides supplementation on anthropometric and glycaemic outcomes. Meta-analyses were performed using random-effects models to calculate the weighted mean difference and 95% confidence interval. There were 30 studies for the systematic review and 23 studies pooled for meta-analysis. Histidine-containing dipeptide groups had a lower waist circumference (WMD [95% CI] = -3.53 cm [-5.65, -1.41], p = 0.001) and HbA1c level (WMD [95% CI] = -0.76% (8.5 mmol/mol) [-1.29% (14.3 mmol/mol), -0.24% (2.8 mmol/mol)], p = 0.004) at follow-up compared with controls. In sensitivity analyses of studies with low risk of bias, waist circumference, HbA1c, and fasting glucose levels (WMD [95% CI] = -0.63 mmol/L [-1.09, -0.18], p = 0.006) were significantly lower in intervention groups versus controls. There was also a trend toward lower fat mass (p = 0.09), insulin resistance (p = 0.07), and higher insulin secretion (p = 0.06) in intervention versus control groups. Supplementation with histidine-containing dipeptides may reduce central obesity and improve glycaemic outcomes. Further studies exploring histidine-containing dipeptide use in obesity and diabetes prevention and treatment are warranted.