Food Liking Enhances the Plasma Response of 2-Arachidonoylglycerol and of Pancreatic Polypeptide upon Modified Sham Feeding in Humans.

Food palatability increases food intake and may lead to overeating. The mechanisms behind this observation are still largely unknown. The aims of this study were the following: 1) to elucidate the plasma responses of endocannabinoids, N-acylethanolamines, and gastrointestinal peptides to a palatable (sweet), unpalatable (bitter), and sensory-acceptable (tasteless control) food, and 2) to verify whether some of these bioactive compounds can serve as plasma biomarkers of food liking in humans. Three puddings providing 60 kcal (35% from proteins, 62% from carbohydrates, and 3% from fats) but with different taste were developed. Twenty healthy subjects (11 women and 9 men; mean age 28 y and BMI 22.7 kg/m(2)), selected because they liked the puddings in the order sweet > control > bitter, participated in a randomized crossover study based on a modified sham feeding (MSF) protocol. Blood samples at baseline and every 5 min up to 20 min after the MSF were analyzed for gastrointestinal peptides, endocannabinoids, and N-acylethanolamines. Thirty minutes after the MSF, energy intake at an ad libitum breakfast was measured. After the MSF, no response was observed in 7 of 9 gastrointestinal peptides measured. The plasma ghrelin concentration at 20 min after the sweet and bitter puddings was 25% lower than after the control pudding (P = 0.04), and the pancreatic polypeptide response after the sweet pudding was 23% greater than after the bitter pudding (P = 0.02). The plasma response of 2-arachidonoylglycerol after the sweet pudding was 37% and 15% higher than after the bitter (P < 0.001) and control (P = 0.03) puddings, respectively. Trends for greater responses of anandamide (P = 0.06), linoleoylethanolamide (P = 0.07), palmitoylethanolamide (P = 0.06), and oleoylethanolamide (P = 0.09) were found after the sweet pudding than after the bitter pudding. No differences in subsequent energy intake were recorded. The data demonstrated that food palatability influenced some plasma endocannabinoid and N-acylethanolamine concentrations during the cephalic phase response and indicated that 2-arachidonoylglycerol and pancreatic polypeptide can be used as biomarkers of food liking in humans.