Casein protein results in higher prandial and exercise induced whole body protein anabolism than whey protein in chronic obstructive pulmonary disease

Abstract

Exercise is known to improve physical functioning and health status in Chronic Obstructive Pulmonary Disease (COPD). Recently, disturbances in protein turnover and amino acid kinetics have been observed after exercise in COPD. The objective was to investigate which dairy protein is able to positively influence the protein metabolic response to exercise in COPD. 8 COPD patients and 8 healthy subjects performed a cycle test on two days while ingesting casein or whey protein. Whole body protein breakdown (WbPB), synthesis (WbPS), splanchnic amino acid extraction (SPE), and NetWbPS (=WbPS-WbPB) were measured using stable isotope methodology during 20 min of exercise (at 50% peak work load of COPD group). The controls performed a second exercise test at the same relative workload. Exercise was followed by 1 h of recovery. In the healthy group, WbPS, SPE, and NetPS were higher during casein than during whey feeding (P<.01). WbPS and NetPS were higher during exercise, independent of exercise intensity (P<.01). NetPS was higher during casein feeding in COPD due to lower WbPB (P<.05). Higher SPE was found during exercise during casein and whey feeding in COPD (P<.05). Lactate levels during exercise were higher in COPD (P<.05) independent of the protein. Post-exercise, lower NetPS values were found independent of protein type in both groups. Casein resulted in more protein anabolism than whey protein which was maintained during and following exercise in COPD. Optimizing protein intake might be of importance for muscle maintenance during daily physical activities in COPD.

Trial registration: ClinicalTrials.gov NCT01418469.

Conflict of interest statement

Disclosure statement

The authors declare that they have no competing interests.

Copyright © 2012 Elsevier Inc. All rights reserved.

Figures

Figure 1

Overview of study design for the healthy controls and the COPD group. The COPD group (lower panel) performed one exercise bout during 20 minutes at 50% of their own peak workload, followed by 60 min recovery. To get the same absolute workload for the control group, the control group (upper panel) cycled at a work rate corresponding to the average of the workload used in the COPD group (exercise bout 1). After a recovery period of one hour, the healthy controls performed an additional cycle ergometer test during 20 minutes at the same relative workload as the COPD subjects (50% of their own peak workload, exercise bout 2) followed by 60 minutes of recovery.

Figure 2

Changes in whole body protein synthesis of the healthy control group (upper panel, n=8) during 20 minutes of low and high intensity exercise both followed by 1 hour of recovery, and the COPD group (lower panel, n=8) during 20 minutes of exercise and 1 hour of recovery, during intake of a casein protein meal (circles) vs. a whey protein meal (squares) provided every 20 min until the end of the test day. Mean values ± 1 SE are shown. Repeated measures mixed model ANOVA: there was a significant protein effect during exercise and recovery in the healthy control group (p

Figure 3

Changes in whole body protein breakdown of the healthy control group (upper panel, n=8) during 20 minutes of low and high intensity exercise both followed by 1 hour of recovery, and the COPD group (lower panel, n=8) during 20 minutes of exercise and 1 hour of recovery, during intake of a casein protein meal (circles) vs. a whey protein meal (squares) provided every 20 min until the end of the test day. Mean values ± 1 SE are shown. Repeated measures mixed model ANOVA: there was a significant protein effect during exercise (p

Figure 4

Changes in Net whole body protein synthesis of the healthy control group (upper panel, n=8) during 20 minutes of low and high intensity exercise both followed by 1 hour of recovery, and the COPD group (lower panel, n=8) during 20 minutes of exercise and 1 hour of recovery, during intake of a casein protein meal (circles) vs. a whey protein meal (squares) provided every 20 min until the end of the test day. Mean values ± 1 SE are shown. Repeated measures mixed model ANOVA: there was a significant protein effect during exercise and recovery in the COPD and control group (p

Figure 5

Changes in splanchnic extraction of the healthy control group (upper panel, n=8) during 20 minutes of low and high intensity exercise both followed by 1 hour of recovery, and the COPD group (lower panel, n=8) during 20 minutes of exercise and 1 hour of recovery, during intake of a casein protein meal (circles) vs. a whey protein meal (squares) provided every 20 min until the end of the test day. Mean values ± 1 SE are shown. Repeated measures mixed model ANOVA: there was a significant protein effect during exercise in the COPD group (p

Figure 6

Changes in BCAA concentration of the healthy control group (upper panel, n=8) during 20 minutes of low and high intensity exercise both followed by 1 hour of recovery, and the COPD group (lower panel, n=8) during 20 minutes of exercise and 1 hour of recovery, during intake of a casein protein meal (circles) vs. a whey protein meal (squares) provided every 20 min until the end of the test day. Mean values ± 1 SE are shown. Repeated measures mixed model ANOVA: there was a significant protein effect during exercise in the COPD group (p

Figure 7

Changes in lactate concentration of the healthy control group (upper panel, n=8) during 20 minutes of low and high intensity exercise both followed by 1 hour of recovery, and the COPD group (lower panel, n=8) during 20 minutes of exercise and 1 hour of recovery, during intake of a casein protein meal (circles) vs. a whey protein meal (squares) provided every 20 min until the end of the test day. Mean values ± 1 SE are shown. Repeated measures mixed model ANOVA: there was a significant time effect during exercise and recovery in the COPD group (p

Figure 8

Changes in NH3 concentration of the healthy control group (upper panel, n=8) during 20 minutes of low and high intensity exercise both followed by 1 hour of recovery, and the COPD group (lower panel, n=8) during 20 minutes of exercise and 1 hour of recovery, during intake of a casein protein meal (circles) vs. a whey protein meal (squares) provided every 20 min until the end of the test day. Mean values ± 1 SE are shown. Simple factorial ANOVA: there was a significant time effect during exercise and recovery during high intensity exercise in the control group (p<0.05). There was no significant protein or protein by time interaction in the COPD and control group.