Appetite control and gastrointestinal hormonal behavior (CCK, GLP-1, PYY 1–36) following low doses of a whey protein-rich nutraceutic

Abstract

Whey proteins represent the most satiating nutrients. In particular, their effects are due to enterohormonal changes (CCK, GLP-1 and PYY 1–36) observed after their exclusive ingestion. Glucomannan has important satiety property due to volume increase following gelification. The aim of the study is the evaluation of subjective rate of hunger and enterohormone concentrations (CCK, GLP-1, PYY 1–36) following oral loading of a mixture containing WP (8 g) or casein (8 g) plus glucomannan (1 g) (Colordiet®, Inpha DUEMILA Srl Lecco, Italy). The study was conducted as a double-blind crossover with five healthy volunteers (BMI 22–26 kg/m2 aging 18–65 years) in acute and a wash-out period of 1 week between the first and the second evaluation. From the analysis of the data, we observe that the load with WP induces a significant decrease in the desire to eat after 90 min (P < 0.0446) when compared with casein. As far as plasma hormones are concerned, there was a significant increase only in GLP-1 at 90 min after WP (P < 0.00166) and 180 min after casein (T0 vs. T180 P = 0.000129). There is a significant correlation between the increase in GLP-1 and decrease of desire to eat (R = −0.93). There is a tendency to the increasing of CCK after 90 min, which is not significant (P = 0.091). These results could be due to (a) the low number of cases or (b) the low dose of protein used. The present study suggests that a mixture of WP plus glucomannan exerts a decrease in the desire to eat which is correlated to enterohormonal modification (GLP-1 increase) despite the low content of protein (8 g) and the presence of glucomannan, which could reduce the fast absorption of WP in relation to the net forming during the gelification of the gastric environment.

Peptide YY mediates the satiety effects of diets enriched with whey protein fractions in male rats

“…Consumption of high-protein diets has often been associated with increased circulating concentrations of gut satiety hormones, especially PYY in both humans (28,29,38,47,48) and rodents (38); however, less is known about the effects of protein quality on PYY-mediated satiety. Circulating PYY concentrations did not differ in human participants who were fed whey, casein, or pea protein-enriched diets (3,4), nor in rats that were fed whey or soy protein for 10 wk (6), whereas PYY mRNA was decreased in the colon of rats after 40 wk of whey protein feeding compared with casein feeding (52). We extend these findings and demonstrate that lactalbumin and lactoferrin diets increased PYY mRNA abundance in the colon, and that whey and lactalbumin increased circulating PYY concentrations, within a week, which is indicative of up-regulated PYY expression and Cumulative food intake (A), mean meal size (B), cumulative number of meals (C ), latency to first meal (D), hourly energy expenditure (E ), and RQ (F ) of obese rats for the initial 6 h of the dark period.…”

“…PYY is synthesized and secreted primarily from the enteroendocrine cells of the distal intestines, with protein being a potent stimulus for their secretion in rats (24). Whey protein was found to be more satiating than casein (25,26) and to increase plasma concentrations of PYY in normal participants (3,(26)(27)(28)(29) and in some (30), but not all, rodent studies (4,6,10); however, others reported a dissociation of protein-induced satiety from circulating PYY concentrations (3,31). Thus, despite reports of dietary proteins being potent PYY secretagogues, there is no direct evidence to support the concept that PYY acts as an endocrine signal to mediate the hypophagic effects of such diets.…”

“…Diets that are enriched in protein are highly satiating (1) and are endorsed for weight loss by several scientific organizations and societies (2). High-protein diets have been reported to decrease hunger and the desire to eat, prolong meal intervals and increase satiety in humans (3)(4)(5), and reduce food intake in rodents (6,7). Among protein sources, the dairy proteins, whey and casein, have been extensively studied for their satiating and weight-loss properties (8,9).…”

Specificity and sensitivity of commercially available assays for glucagon‐like peptide‐1 (GLP‐1): implications for GLP‐1 measurements in clinical studies

“…A brief look at some of the published values for GLP-1 concentrations in clinical studies also reveals considerable heterogeneity. For instance, mean fasting levels of total GLP-1 in healthy subjects range from <1 pmol/l (Alpco; [15]), 4-5 pmol/l (MSD; [16]); approximately 6 pmol/l (Phoenix; [17]), 18 pmol/l (Linco -now Millipore -total RIA; [18]) to approximately 44 pmol/l (Millipore total ELISA; [19]), which partly reflects the differing specificities as described above (Alpco, Phoenix and MSD kits tending to underestimate levels compared with the two Millipore assays). At the higher end of the endogenous GLP-1 concentration range, most studies report increased postprandial levels in patients after RYGB, although absolute concentrations and magnitude of change vary considerably.…”

Functional food relevance of whey protein: A review of recent findings and scopes ahead

“…The anorectic effect and consequent insulin response of whey proteins are co-ordinated by cholecystokinin, glucagonlike peptide-1 (GLP-1), gastric inhibitory polypeptide (GIP ), peptide YY (PYY ), and ghrelin (Jakubowicz & Froy, 2013;Sukkar et al, 2013). From the result of a randomized study, it was inferred that pre-meal consumption of whey protein moderates post-meal glycaemia by both insulin-dependent and insulinindependent pathways (Akhavan et al, 2014).…”