Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Whey protein but not soy protein supplementation alters body weight and composition in free-living overweight and obese adults

Authors
item Stote, Kim
item Paul, David - UNIV OF IDAHO
item Harris, Gabriel - NORTH CAROLINA STATE UNIV
item Rumpler, William
item Clevidence, Beverly
item Baer, David

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 16, 2011
Publication Date: August 1, 2011
Citation: Stote, K.S., Paul, D.R., Harris, G.K., Rumpler, W.V., Clevidence, B.A., Baer, D.J. 2011. Whey protein but not soy protein supplementation alters body weight and composition in free-living overweight and obese adults. Journal of Nutrition. 141:1489-94.

Interpretive Summary: The macronutrient that appears to be most satiating is dietary protein and the source of dietary protein may influence satiety and food intake. Few long-term research studies have investigated the effects of whey protein, a protein found in dairy products, on biomarkers of satiety, such as plasma ghrelin, in overweight and obese adults. Ghrelin is a hormone that is produced primarily by the stomach and small intestine; it may serve as a hunger signal. The effect of consumption of supplemental whey protein, soy protein, and an isocaloric amount of carbohydrate on subjective and physiologic biomarkers of satiety in free-living overweight and obese adults was evaluated. Ninety subjects were randomly assigned for 23 weeks to one of three treatments along with consuming their free-living diet: 1) 60 g/d of whey protein, 2) 60 g/d of soy protein, or 3) a carbohydrate control group. The treatments were consumed as a beverage with breakfast and the evening meal. Biomarkers measured at baseline and at the end of the study included ghrelin, peptide YY, leptin, and adiponectin. These biomarkers are associated with hunger and energy regulation. Subjective satiety was assessed daily by the use of visual analog scales which evaluate hunger, desire to eat, and fullness. Dietary intake was determined by 24-h dietary recalls collected every 10 days. Results showed that after 23 weeks, subjects consuming supplemental whey protein had lower ghrelin concentrations than did subjects consuming soy protein or an isocaloric carbohydrate treatment. No significant treatment effects were observed on peptide YY, leptin, adiponectin, or energy and macronutrient intakes. Whey protein suppressed ghrelin concentrations when compared with soy protein and the carbohydrate treatment. These findings indicate that whey protein supplementation may be more satiating than soy protein and carbohydrate in free-living overweight and obese adults. These findings will be important to scientists interested in components in dairy foods and their effects on hunger, satiety, and food intake regulation.

Technical Abstract: The most satiating macronutrient appears to be dietary protein; the source of the dietary protein may influence satiety and food intake. Few long-term clinical trials have investigated the effects of whey protein on biomarkers of satiety, such as plasma ghrelin, in overweight and obese adults. The effect of consumption of supplemental whey protein, soy protein, and an isocaloric amount of carbohydrate on subjective and physiologic biomarkers of satiety in free-living overweight and obese adults was evaluated. Ninety subjects were studied in a double-blinded parallel design. The subjects were randomly assigned for 23 weeks to one of three treatment groups along with consuming their free-living diet: 1) 60 g/d of whey protein, 2) 60 g/d of soy protein, or 3) a carbohydrate control group. The treatments were consumed as a beverage with breakfast and the evening meal. Biomarkers measured at baseline and at the end of the study included ghrelin, peptide YY, leptin, and adiponectin. Subjective satiety was assessed daily by use of visual analog scales. Dietary intake was determined by 24-h dietary recalls collected every 10 days. Results showed that after 23 weeks, subjects consuming supplemental whey protein had lower ghrelin concentrations than did subjects consuming soy protein or the isocaloric carbohydrate treatment. No significant treatment effects were observed on peptide YY, leptin, adiponectin, and energy and macronutrient intakes. Whey protein suppressed ghrelin concentrations when compared with soy protein and the isocaloric carbohydrate treatment. Whey protein supplementation may be more satiating than soy protein and carbohydrate in free-living overweight and obese adults.

Last Modified: 7/30/2014