Postprandial blood amino acid concentrations in older adults after consumption of dairy products: The role of the dairy matrix

Astrid M.H Horstman,Renate A Ganzevles,Urszula Kudla,Alwine F.M Kardinaal,Joost J.G.C Van Den Borne,Thom Huppertz

doi:10.1016/j.idairyj.2020.104890

Astrid M.H Horstman, Renate A Ganzevles + Show 4 more

Open Access

https://doi.org/10.1016/j.idairyj.2020.104890

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Abstract

This study investigated postprandial aminoacidemia after consumption of different dairy products using a single-blinded cross-over design wherein 10 participants (66.7 ± 4.3 y) received low-fat UHT-treated milk (LF–UHT), low-fat pasteurised milk (LF–PAS), full-fat UHT-treated milk (FF–UHT), full-fat pasteurised milk (FF–PAS), low-fat yoghurt, full-fat cheese, whey protein concentrate (WPC), and micellar casein isolate (MCI). Blood samples were collected postabsorptive and (up to 5 h) postprandial and maximal amino acid concentration (Cmax), timepoint corresponding to Cmax (Tmax) and incremental area under the curve (iAUC) were determined. The highest increase in blood essential amino acid (EAA) levels occurred after WPC and yoghurt consumption, whereas MCI and cheese consumption resulted in extended EAA response curves. Fat delayed the postprandial EAA blood response (FF–UHT versus LF–UHT and FF–PAS versus LF–UHT), whereas no effect of heating milk was found (P > 0.05). The findings highlight that the product matrix could be as important as protein composition in postprandial aminoacidemia.

Highlights

This is because whey protein contains more leucine (Boirie et al, 1997; Dangin et al, 2001; Tang, Moore, Kujbida, Tarnopolsky, & Phillips, 2009) and typically has faster digestion and absorption kinetics than casein, resulting in a greater increase in postprandial blood amino acid availability, thereby stimulating muscle protein synthesis (Bohe, Low, Wolfe, & Rennie, 2003; Boirie et al, 1997; Dangin et al, 2001; Koopman et al, 2009; Pennings et al, 2011; Walrand et al, 2016)
Cmax for glucose significantly differed between LFePAS on the one hand, and whey protein concentrate (WPC) (P < 0.001), FFePAS (P 1⁄4 0.036) and yoghurt (P 1⁄4 0.001) on the other hand. incremental area under the curve (iAUC) for glucose was not overall different between products (P 1⁄4 0.99)
A stronger insulin response for WPC was found than for micellar casein isolate (MCI) (P < 0.001), which was expected considering the more branched-chain amino acids in whey and faster digestion kinetics compared with casein (Nilsson, Stenberg, Frid, Holst, & Bjorck, 2004; Pal & Ellis, 2010)

Summary

Introduction

It has been frequently shown that ingesting whey protein leads to a faster and greater increase in blood essential amino acids and especially leucine concentration than the other class of milk proteins, i.e., casein (Boirie et al, 1997; Dangin et al, 2001; Koopman et al, 2009; Pennings et al, 2011). We investigated the effect of fat (low-fat versus fullfat) and heat treatment (pasteurisation versus UHT treatment)

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