Introduction: We have previously reported that carnosine supplementation, an over-the-counter food supplement, prevented worsening of glucose metabolism in humans but did not change plasma lipid levels. However, studies in rodents indicated that carnosine has been shown to improve dyslipidaemia, reduce oxidation and glycation of low density lipoprotein and reduce development of atherosclerosis. The effect of carnosine on human plasma lipidome has thus far not been investigated.
Objective: To determine whether carnosine supplementation improves the plasma lipidome in overweight and obese otherwise healthy individuals.
Methods: Lipidomic analysis was performed by LC/ES-MS in 24 overweight and obese non-diabetic adults: 13 were randomly assigned to 2g carnosine daily and 11 to placebo and treated for 12 weeks. Insulin sensitivity was calculated using homeostatic model assessment of insulin resistance (HOMA-IR). Triple quadrupole mass spectrometer was used to measure urinary carnosine. Serum carnosinase activity was quantified by fluorometric determination of liberated histidine after carnosine addition.
Results: Carnosine supplementation maintained the levels of trihexosylceramide (mean % change ± SD: 0.7±11 carnosine vs -12.6±16 placebo, p=0.05) and phosphatidylserine (3.2±39 carnosine vs 130±520 placebo, p=0.03) lipid classes compared to placebo. Change in trihexosylceramide was inversely correlated with change in fasting insulin (r=-0.4, p=0.02), HOMA-IR (r=-0.5, p=0.02) and carnosinase 1 (r=-0.3, p=0.05) and positively with urinary carnosine levels (r=0.4, p=0.02), and remained significant after adjustment for age, sex and change in body mass index (all p<0.01) except for urine carnosine. No other cardiometabolic parameters were associated with trihexosylceramide. Phosphatidylserine lipid class did not correlate with any cardiometabolic parameters.
Conclusion: We suggest that carnosine supplementation may have beneficial effects on plasma lipidome and contribute to prevention of T2DM and CVD. Future long term studies with larger sample sizes are highly warranted.