Quantitation of carnosine in humans plasma after dietary consumption of beef.

Carnosine (beta-alanyl-L-histidine) is a dipeptide found in the muscle foods that has been postulated to be a bioactive food component. The objective of this research was to determine the concentration of carnosine in human plasma after ingestion of beef. Nine males and nine females were recruited for the study. Food devoid of meat products was given to the subjects so that they did not consume carnosine for 48 h prior to the test. Subjects fasted for 12 h and then had blood withdrawn prior to a meal containing 200 g of ground beef. Additional blood samples were collected over the following 24 h and carnosine concentrations were determined by HPLC. The cooked ground beef used in the study contained 52% water, 24% protein, 22% fat, and 124 mg of carnosine/100 g of beef. No plasma carnosine was detected in subjects before the consumption of the beef. Carnosine was detected in plasma 15 min after beef consumption. Plasma carnosine concentrations continued to increase with a maximum (32.7 mg of carnosine/L of plasma) being recorded 2.5 h after consumption. Carnosine concentrations then decreased until no carnosine could be detected at 5.5 h postconsumption. These results indicate that dietary carnosine is absorbed into human plasma after the consumption of beef. Since carnosine has several potential health benefits, evidence of its bioavailability suggests that it could be a bioactive food component.