Amino Acid Kinetics in Blood After Consuming Different Milk Protein Supplements

Study Overview
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Brief Summary
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The aim of this study is to investigate the amino acid kinetics in blood after a bout of strength training and ingestion of different milk protein supplements (native whey, whey protein concentrate 80, hydrolysed whey, microparticulated whey and milk) The investigators hypothesize that native whey will give a faster and higher rise in blood concentrations of leucine compared to the other milk protein supplements.

Detailed Description
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Increasing or maintaining muscle mass is of great importance for populations ranging from athletes to patients and elderly. Resistance exercise and protein ingestion are two of the most potent stimulators of muscle protein synthesis. Both the physical characteristic of proteins (e.g. different digestion rates of whey and casein) and the amino acid composition, affects the potential of a certain protein to stimulate muscle protein synthesis. Given its superior ability to rapidly increase blood leucine concentrations to high levels, whey is often considered the most potent protein source to stimulate muscle protein synthesis. Native whey protein is produced by filtration of unprocessed milk. Consequently, native whey has different characteristics than WPC-80, which is exposed to heating and acidification. Because of the direct filtration of unprocessed milk, native whey is a more intact protein compared with WPC-80. Of special interest is the higher amounts of leucine in native whey. The aim of this double-blinded randomized 5-arm cross-over study is to compare amino acid kinetics in blood after a bout of strength training and ingestion of 20 grams of high quality, but distinct, dairy protein supplements (native whey, whey protein concentrate 80, hydrolysed whey, microparticulated whey and milk). Furthermore, the investigators investigate whether differences in amino acid kinetics affect acute blood glucose and urea response, as well as recovery of muscle function after a bout of strength training. The investigators hypothesize that native whey will give a faster and higher rise in blood concentrations of leucine compared to the other protein supplements.

Official Title
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Does Native Whey Induce Greater Blood Leucine Concentrations Than Other Whey Protein Supplements and Milk: A Randomized Controlled Trial?

Conditions
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Healthy Participants

Intervention / Treatment
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* Other: Strength Training
* Dietary Supplement: Milk 1%
* Dietary Supplement: Whey protein concentrate 80 (WPC-80)
* Dietary Supplement: Microparticulated whey
* Dietary Supplement: Hydrolyzed whey
* Dietary Supplement: Native whey


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy in the sense that they can conduct training and testing Able to understand Norwegian language written and oral Exclusion Criteria: Diseases or injuries contraindicating participation Use of dietary supplements (e.g. proteins, vitamins and creatine) Lactose intolerance Allergy to milk Allergy towards local anesthetics (xylocain)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Milk 1%<br>Participants performed a bout of strength training and consumed 636 ml of a protein supplement | Other: Strength Training<br> <br> Dietary Supplement: Milk 1%<br> <br> * Other names: Protein supplementation;|
| Experimental: Whey protein concentrate 80 (WPC-80)<br>Participants performed a bout of strength training and consumed 636 ml of a protein supplement | Other: Strength Training<br> <br> Dietary Supplement: Whey protein concentrate 80 (WPC-80)<br> <br> * Other names: Protein supplementation;|
| Experimental: Microparticulated whey<br>Participants performed a bout of strength training and consumed 636 ml of a protein supplement | Other: Strength Training<br> <br> Dietary Supplement: Microparticulated whey<br> <br> * Other names: Protein supplementation;|
| Experimental: Hydrolyzed whey<br>Participants performed a bout of strength training and consumed 636 ml of a protein supplement | Other: Strength Training<br> <br> Dietary Supplement: Hydrolyzed whey<br> <br> * Other names: Protein supplementation;|
| Experimental: Native whey<br>Participants performed a bout of strength training and consumed 636 ml of a protein supplement | Other: Strength Training<br> <br> Dietary Supplement: Native whey<br> <br> * Other names: Protein supplementation;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma amino acid concentration change from baseline |  | Blood collected at 0, 30, 45, 60, 90 and 120 min after consumption of protein supplements | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum glucose change from baseline |  | Blood collected at 0, 30, 45, 60, 90 and 120 min after consumption of protein supplements | 
| Serum urea change from baseline |  | Blood collected at 0, 30, 45, 60, 90 and 120 min after consumption of protein supplements. For milk and native whey blood was collected at two additional time points: 22 and 30 hours after consumption of protein supplements | 
| Muscle force generating capacity change from baseline | Measured as unilateral isometric knee extension force (Nm) with 90° in the hip and knee joints. | Measured before and at 0, 6, 22 and 30 hours after exercise. Only measured after milk and native whey | 
| Jump height change from baseline | Measured as counter movement jump on a force plate | Measured before and at 0, 6, 22 and 30 hours after exercise. Only measured after milk and native whey | 
| Serum creatine kinase change from baseline |  | Blood collected at 0, 30, 45, 60, 90 and 120 min after consumption of protein supplements. For milk and native whey blood was collected at two additional time points: 22 and 30 hours after consumption of protein supplements | 
| Muscle soreness change from baseline | Measured for m. quadriceps and m. pectoralis major on a visual analog pain scale | Measured before and at 0, 6, 22 and 30 hours after exercise. Only measured after milk and native whey |