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Postprandial leucine and insulin responses and toxicological effects of a novel whey protein hydrolysate-based supplement in rats

Ryan G Toedebusch1, Thomas E Childs1, Shari R Hamilton2, Jan R Crowley34, Frank W Booth1567 and Michael D Roberts1*

Author Affiliations

1 Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA

2 Research Animal Diagnostics Laboratory (RADIL), Columbia, MO, USA

3 NIH/NCRR Mass Spectrometry Resource, Washington University, St. Louis, MO, USA

4 School of Medicine, Division of Endocrinology, Metabolism, Lipid Research, Washington University, St. Louis, MO, USA

5 Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA

6 Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO, USA

7 Department of Nutrition and Exercise Physiology, College of Environmental Health Sciences, University of Missouri, Columbia, MO, USA

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Journal of the International Society of Sports Nutrition 2012, 9:24  doi:10.1186/1550-2783-9-24

Published: 6 June 2012


The purpose of this study was: aim 1) compare insulin and leucine serum responses after feeding a novel hydrolyzed whey protein (WPH)-based supplement versus a whey protein isolate (WPI) in rats during the post-absorptive state, and aim 2) to perform a thorough toxicological analysis on rats that consume different doses of the novel WPH-based supplement over a 30-day period. In male Wistar rats (~250 g, n = 40), serum insulin and leucine concentrations were quantified up to 120 min after one human equivalent dose of a WPI or the WPH-based supplement. In a second cohort of rats (~250 g, n = 20), we examined serum/blood and liver/kidney histopathological markers after 30 days of feeding low (1human equivalent dose), medium (3 doses) and high (6 doses) amounts of the WPH-based supplement. In aim 1, higher leucine levels existed at 15 min after WPH vs. WPI ingestion (p = 0.04) followed by higher insulin concentrations at 60 min (p = 0.002). In aim 2, liver and kidney histopathology/toxicology markers were not different 30 days after feeding with low, medium, high dose WPH-based supplementation or water only. There were no between-condition differences in body fat or lean mass or circulating clinical chemistry markers following the 30-day feeding intervention in aim 2. In comparison to WPI, acute ingestion of a novel WPH-based supplement resulted in a higher transient leucine response with a sequential increase in insulin. Furthermore, chronic ingestion of the tested whey protein hydrolysate supplement appears safe.

Diet; Leucine; Whey hydrolysate