Postprandial acylated ghrelin status following fat and protein manipulation of meals in healthy young women

The aim of the present study was to investigate the postprandial effect of diet composition on circulating acylated ghrelin levels in healthy women. A randomized cross-over study of three experimental treatments was performed. A total of 11 healthy young women of normal body weight completed the study. All 11 subjects consumed three iso-energetic meals of different macronutrient composition, a balanced meal (50% carbohydrates, 30% fat and 20% protein), a high-fat meal (45% carbohydrates, 45% fat and 10% protein) and a high-protein meal (45% carbohydrates, 20% fat and 35% protein), for breakfast on separate days. The test meals were administered 1 month apart. Blood samples were withdrawn immediately before and at 15, 30, 60, 120 and 180 min after the test meal for measurement of plasma acylated ghrelin, as well as serum glucose, insulin and triacylglycerol (triglyceride) levels. Acylated ghrelin fell significantly after ingestion of both the balanced and high-protein meals. Ghrelin persisted at significantly lower levels than baseline for a longer duration following the high-protein meal (P<0.05 at 15, 30, 60 and 120 min) compared with the balanced meal (P<0.05 at 30 and 60 min). Moreover, acylated ghrelin levels correlated negatively with the postprandial insulin levels. In conclusion, postprandial changes in acylated plasma ghrelin depend on the macronutrient composition of the meal and are possibly influenced by insulin.