Dietary Carnitine and Carnosine Increase Body Lean in Healthy Cats in a Preliminary Study

SIMPLE SUMMARY: Cats, like mammals in general, experience lean body mass loss in later life. This study shows that two dietary interventions offset that loss: L-carnitine and carnosine. The combination did not change body lean. Interestingly, the combination resulted in an increased circulating concentration of 8 of the 10 cytokines measured, while L-carnitine alone resulted in decreased concentrations. Thus, L-carnitine could benefit the healthy cat while in some disease states it may be beneficial to increase both L-carnitine and carnosine. ABSTRACT: The need to maintain body lean as cats age is shown in both health and disease. In healthy cats, body lean is associated with enhanced movement and overall longevity. In many disease states (i.e., renal disease, obesity), an enhanced or minimally maximal support of body lean is associated with quality of life and is a nutritional goal in aiding in the management of the disease. This study was designed to investigate the effect of these two dietary components and their combination on body composition and circulating factors of health, including metabolomics analysis and cytokine concentration. The foods that were fed for 169 days to four groups of cats and consisted of control food (formulated to meet the nutritional needs of all adult cats), carnitine-enhanced food (control food plus 300 mg/kg L-carnitine), carnosine-enhanced food (control food plus 1000 mg/kg carnosine), and food enhanced with both (control plus 300 mg/kg carnitine and 1000 mg/kg carnosine). Dietary enhancement with L-carnitine and carnosine increased body lean at the end of the study compared to the cats consuming the control food or the combination food. The cats consuming L-carnitine alone had a decreased concentration of circulating cytokines, while those consuming the combination food had an increased concentration of glucose, pyruvate, succinate, and circulating cytokines.