What happens when you compare hydrolyzed whey protein to its counterpart, native whey concentrate? A recently published study took the metabolomics approach and examined the differences between rodents fed either hydrolyzed whey protein or whey protein concentrate. Although both cause an elevation in amino acids (as we’d expect), the whey protein hydrolysate produced higher levels of isoleucine and valine, two of the three branched chain aminos. In addition, the hydrolyzed version had an effect on liberating fatty acids that was not seen with the concentrate version.

Good news for anyone using hydrolyzed whey protein instead of concentrate…here’s the study:

Applied Physiology, Nutrition, and Metabolism, 2014, 39(2): 158-167, 10.1139/apnm-2013-0148

Comparing serum responses to acute feedings of an extensively hydrolyzed whey protein concentrate versus a native whey protein concentrate in rats: a metabolomics approach

Michael D. Roberts,a,* Clayton L. Cruthirds,a Christopher M. Lockwood,b Kirk Pappan,c Thomas E. Childs,a Joseph M. Company,a Jacob D. Brown,a Ryan G. Toedebusch,a Frank W. Bootha,d,e,f

We examined how gavage feeding extensively hydrolyzed whey protein (WPH) versus a native whey protein concentrate (WPC) transiently affected serum biochemical profiles in rodents. Male Wistar rats (250–300 g) were 8 h fasted and subsequently fed isonitrogenous amounts of WPH or WPC, or remained unfed (control). Animals were sacrificed 15 min, 30 min, and 60 min post-gavage for serum extraction, and serum was analyzed using untargeted global metabolic profiling via gas chromatography/mass spectrometry (MS) and liquid chromatography/MS/MS platforms. We detected 333 serum metabolites amongst the experimental and control groups. Both WPH and WPC generally increased amino acids (1.2–2.8-fold), branched-chain amino acids (1.2–1.7-fold), and serum di- and oligo-peptides (1.1–2.7-fold) over the 60 min time course compared with control (q < 0.05). However, WPH increased lysine (false discovery rate using a q-value <0.05) and tended to increase isoleucine and valine 15 min post-feeding (q < 0.10) as well as aspartylleucine 30 min post-feeding compared with WPC (q < 0.05). While both protein sources led to a dramatic increase in free fatty acids compared with control (up to 6-fold increases, q < 0.05), WPH also uniquely resulted in a 30 min post-feeding elevation in free fatty acids compared with WPC (q < 0.05), an effect which may be due to the robust 30 min postprandial increase in epinephrine in the WPH cohort. These data provide a unique postprandial time-course perspective on how WPH versus WPC feedings affect circulating biochemicals and will guide future research comparing these 2 protein sources.