Acute effect of a cod protein hydrolysate on postprandial acylated ghrelin concentration and sensations associated with appetite in healthy subjects: a double-blind crossover trial

BACKGROUND: Fish protein hydrolysates are suggested to contain bioactive sequences capable of affecting metabolic pathways involved in the regulation of glucose metabolism and body weight when consumed in low doses. Modulation of the appetite-regulating hormone ghrelin may explain suppression of insulin secretion and weight loss observed in previous studies with fish protein hydrolysates. OBJECTIVE: This study aimed to assess the effect of a single, low dose of cod protein hydrolysate (CPH) before a breakfast meal on postprandial acylated ghrelin concentration and sensations associated with appetite in healthy subjects. DESIGN: In this explorative trial with a crossover design, 41 healthy individuals (15 males and 26 females, age 51 ± 6 years) completed 2 study days separated by 4–7 days of washout. On both study days, a test drink containing 20 mg CPH or casein (control) per kg body weight was given immediately before a standardized breakfast meal. Acylated ghrelin concentrations were measured before test drink/breakfast (baseline) and at time 0, 20, 40, 80, and 180 min postprandially. Sensations associated with appetite were measured by a Visual Analog Scale (100 mm) at baseline and 0, 20, 40, and 180 min postprandially. RESULTS: Statistically, no difference was observed between CPH and control for postprandial acylated ghrelin concentrations (mean difference geometric mean: 1.05 pg/mL, 95% confidence interval [CI]: 0.97–1.13, P = 0.266), or between the total area under the curve (tAUC) for acylated ghrelin after CPH (tAUC = 17518 pg/mL × min, 95% CI: 0–47941) and control (tAUC = 17272 pg/mL × min, 95% CI: 0–48048, P = 0.991). No differences were found between CPH and control for sensation of appetite, according to tAUC of postprandial scores for satiety (P = 0.794) and the feeling of fullness (P = 0.996). CONCLUSION: We did not find an effect of a single dose of CPH on postprandial concentrations of acylated ghrelin or sensations related to feeling of hunger, compared to control. Further studies should aim to evaluate the effect of a supplement with CPH given daily over a period of time.