Increased protein intake in healthy males exposed to an appetite modulating, whey-derived peptide hydrolysate

The identification of food-grade bioactives with proven orexigenic effects would mark significant progress in the treatment of disease-related malnutrition. To investigate the effects of two milk-derived hydrolysates (UL-2-141 (whey hydrolysate) and MF1145 (casein hydrolysate)) on appetite and energy intake in healthy humans, a single-blind, placebo-controlled, 3-arm cross-over feeding trial was conducted in 22 fasted, cannulated healthy male volunteers. Participants received 26 mg kg^-1 of both hydrolysates and placebo and were observed from morning to afternoon with a set breakfast and <i>ad libitum</i> lunch. Mean total daily energy and protein intakes when treated with placebo were 2673 kcal (95% CI: 2247-3100 kcal) and 128 g (95% CI: 105-152 g), respectively. Energy intake for either treatment was not significantly different from that for placebo (<i>p</i> = 0.266 for UL-2-141 and <i>p</i> = 0.796 for MF1145). Protein intake significantly increased in the UL-2-141 arm compared with that in placebo (+23 g, <i>p</i> = 0.044), but it did not significantly increase in the MF1145 arm (+13 g, <i>p</i> = 0.189). Appetite, hunger and satiety responses on VAS for either treatment were not significantly different from those obtained for placebo. GLP-1 was significantly higher pre-lunch in the UL-2-141 arm than in placebo (+8 pmol L^-1, <i>p</i> = 0.01) and in the MF1145 arm (+7 pmol L^-1, <i>p</i> = 0.039). GH was significantly lower pre-lunch only in the UL-2-141 arm than in placebo (-133 pg mL^-1, <i>p</i> = 0.027). Protein intake was significantly increased in the UL-2-141 arm, demonstrating appetite modulation, potentially <i>via</i> indirect or delayed stimulation of the ghrelin receptor. Since healthy adults are often not in tune with their physiological hunger, repeating the study in subjects with established anorexia may be prudent.