The effects of a beef and fish meal on plasma amino acids, insulin and glucagon levels

Abstract

In vivo studies have reported the effects of various protein meals on pancreatic hormone secretion. The purpose of the present investigation was to compare the plasma insulin, glucagon and amino acid variations in response to a beef or a fish meal with comparable amino acid content. It was found that the plasma insulin levels increased significantly more with the beef steak meal (from 46.2 ± 3.5 to 153.2 ± 12.6 pmol/l) than with the cod fillet (from 47.8 ± 3.1 to 104.2 ± 9.7). The increase in plasma glucagon following the beef meal (from 64.2 ± 8.1 to 139.4 ± 21.9) was not significantly different from that of the fish meal (from 64.2 ± 7.6 to 119.8 ± 17.8). The increase in plasma amino acids was comparable for both meals except for arginine and lysine which were higher with fish feeding and for histidine when beef was fed. The plama levels of histidine were 30 μmol/l compared to 10μmol/l for the fish meal. This difference may be related to the fact that carnosine, a dipeptide composed of histidine and beta-alanine, is found in high concentrations in beef muscles but is relatively absent in cod fillets. Postprandial studies on time-related variations of plasma histidine and on digestibility or rate of absorption of beef and fish meat are needed in order to identify the factor involved in the difference in insulin secretion between these two nutrients.