Whey Proteins Reduce Appetite, Stimulate Anorexigenic Gastrointestinal Peptides and Improve Glucometabolic Homeostasis in Young Obese Women

Abstract

Introduction: Proteins, particularly whey proteins, represent the most satiating macronutrient in animals and humans. A dietetic regimen based on proteins enriched preload before eating might be a strategy to counteract obesity. Aims and Methods: The aim of the present study was to evaluate the effects of an isocaloric drink containing whey proteins or maltodextrins (preload) on appetite (satiety/hunger measured by a visual analogue scale or VAS), glucometabolic control (blood glucose/insulin), and anorexigenic gastrointestinal peptides (pancreatic polypeptide or PP, glucagon-like peptide 1 or GLP-1 and peptide YY or PYY) in a cohort of obese young women (n = 9; age: 18.1 ± 3.0 years; body mass index, BMI: 38.8 ± 4.5 kg/m2). After two and a half hours, they were administered with a mixed meal at a fixed dose; satiety and hunger were measured by VAS. Results: Each drink significantly augmented satiety and reduced hunger, and the effects were more evident with whey proteins than maltodextrins. Similarly, there were significant increases in GLP-1 and PYY levels (but not PP) after the ingestion of each drink; these anorexigenic responses were higher with whey proteins than maltodextrins. While insulinemia identically increased after each drink, whey proteins induced a lower glycemic response than maltodextrins. No differences in satiety and hunger were found after the meal, which is presumably due to the late administration of the meal test, when the hypophagic effect of whey proteins was disappearing. Conclusions: While whey proteins actually reduce appetite, stimulate anorexigenic gastrointestinal peptides, and improve glucometabolic homeostasis in young obese women, further additional studies are mandatory to demonstrate their hypophagic effects in obese subjects, when administered as preload before eating.

The Appetite−Suppressant and GLP-1-Stimulating Effects of Whey Proteins in Obese Subjects are Associated with Increased Circulating Levels of Specific Amino Acids

“…In fact, among isoleucine, leucine, lysine, methionine, phenylalanine, proline, tyrosine, and valine, no amino acid was positively correlated with circulating levels of PYY. Nevertheless, this does not mean that PYY has no definite role in the appetite-suppressant effect of (other components of) whey proteins (e.g., GMP, glycomacropeptide), which, in the present study and others, stimulated a higher secretion of PYY than that ensuing the intake of maltodextrin [6,9].…”

“…Among different sources of proteins, whey proteins seem to be the most effective [4]. Several mechanisms have been invoked to explain the appetite-suppressant and weight-losing effects that whey proteins produce when administered to normal weight or obese subjects [5]: secretion of gastrointestinal anorexigenic peptides [6][7][8][9], stimulation of energy expenditure via an increased thermogenesis [10], and direct actions on specific hypothalamic areas involved in the regulation of food intake [11].…”

Protein, amino acids and obesity treatment

“…Recent studies also focused on whey protein impact on specific age groups. In 9 adolescent obese women, enriching a drink with whey protein -used as preload for lunch -incurs less hunger with more satiety sensations, lower blood sugar levels and higher anorexigenic hormone secretion compared to a maltodextrin-enriched beverage [29]. In older sarcopenic populations, a meta-analysis focused on the effect of exercise combined with nutrition in sarcopenic obese subjects [19].…”

Peptides from Natural or Rationally Designed Sources Can Be Used in Overweight, Obesity, and Type 2 Diabetes Therapies

“…The gastrointestinal digestion of whey protein leads to generation of many bioactive peptides and amino acids [229,245], which stimulate several gut hormones associated with food intake regulation, such as cholecystokinin (CCK), PYY, and ghrelin [246][247][248][249]. Whey protein was shown to increase the release of CCK and PYY and reduce ghrelin secretion, underlying a potential role in hunger suppression via reduced food intake and increased satiety in men and woman with obesity [250,251].…”