Background: Adipokines play an important role in the pathophysiology of type 2 diabetes and cardiovascular diseases. We have previously shown that carnosine supplementation improved glucose metabolism in non-diabetic individuals. We aimed to investigate whether the improvement in glucose metabolism was modulated by adipokines.
Methods: Twenty-two overweight and obese otherwise healthy adults were randomly assigned to receive either 2g of carnosine (n=13) or identical placebo (n=9) for 12 weeks. Serum adiponectin, adipsin, leptin and resistin were analysed using a bead-based multiplex assay (LEGENDPlex™, BioLegend). Urinary carnosine, carnosine propanal and propanol were measured by mass spectrometry.
Results: Carnosine supplementation decreased resistin levels compared to placebo (mean change from baseline: -35 ± 83 carnosine vs 35 ± 55 ng/ml placebo, p=0.04). There was also a trend for reduction in leptin levels after carnosine supplementation (-76 ± 165 carnosine vs 35 ± 55 ng/ml placebo, p=0.06). Adiponectin and adipsin levels were not different between the groups (both p>0.1). Change in leptin and resistin were inversely related to change in levels 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 propanol (r=-0.61, p=0.002; r =- 0.61, p=0.002, respectively) and remained significant after adjustment for age, sex and body mass index (all p<0.001). Leptin and resistin levels did not correlate with markers of glucose metabolism (all p>0.1).
Conclusion: These findings suggest that carnosine supplementation might reduce serum adipokines associated with obesity and insulin resistance. Future trials with larger sample sizes are needed.