Carnosine Supplementation Improves Serum Resistin Concentrations in Overweight or Obese but Otherwise Healthy Sedentary Adults—Results From Randomised Controlled Trial

Adipokines play an important role in the regulation of glucose metabolism. We have previously shown that carnosine supplementation in overweight or obese nondiabetic individuals improved glucose metabolism but did not change adiponectin levels, however its effect on other adipokines has not been investigated. We aimed to determine the effect of carnosine supplementation on serum adipsin, resistin and leptin concentrations in these individuals. Twenty-two overweight or obese otherwise healthy adults were randomly assigned to receive either 2g of carnosine (n=13) or identically looking placebo (n=9) for 12 weeks. Serum adipsin, leptin and resistin were analysed using a bead-based multiplex assay (LEGENDPlex™, BioLegend, CA). Carnosine supplementation decreased serum resistin concentrations compared to placebo (mean change from baseline: -35 ± 83 carnosine vs. 35 ± 55 ng/ml placebo, p=0.04). There was a trend for a reduction in serum leptin concentrations after carnosine supplementation (-76 ± 165 ng/ml carnosine vs. 20 ± 28 ng/ml placebo, p=0.06). Change in leptin and resistin were inversely related to change in concentrations of urinary carnosine (r =-0.72, p = 0.0002; r= -0.67, p=0.0009, respectively), carnosine-propanal (r= -0.56, p=0.005; r= -0.63, p=0.001, respectively) and carnosine-propanol (r=-0.61, p=0.002; r = -0.60, p=0.002, respectively). There were no differences between groups in change in adipsin concentrations (both p<0.1). Our findings suggest that carnosine supplementation may normalise some but not all serum adipokine concentrations involved in glucose metabolism in overweight and obese individuals. Further clinical trials with larger samples are needed to confirm these results.