Whey vs Casein to Combat Post-inflammatory Protein and Muscle Waste in Acute Disease

Whey vs Casein to Combat Post-inflammatory Protein and Muscle Waste - Combining Endotoxemia, Immobilisation and Fasting in Healthy Young Males in a New Model of Acute Febrile Disease

This study compares three different protein supplements (casein, whey and leucine-enriched whey) and their effect on post-inflammatory muscle waste in a model of acute disease. Each test person will undergo all three interventions. It is believed that leucine is the primary driver of muscle protein synthesis and therefore we hypothesize that leucine-enriched whey and whey are superior to casein in combating post-inflammatory muscle waste, because of its higher leucine content (16%, 11% and 9% leucine, respectively).

Background: Acute illness is accompanied by infection/inflammation, anorexia and immobilization all contributing to muscle loss, making nutritional supplement optimization an obvious target for investigation and eventually clinical intervention. In the clinical setting large heterogenicity among patients complicates investigations of muscle metabolism during acute illness. Therefore we introduce a disease model by combining "Inflammation + 36 hour fast and bedrest". Inflammation/febrile illness will be initiated by using the well-established "human endotoxemia model" with a bolus injection of Escherichia coli lipopolysaccharide (LPS), known to cause inflammation comparable with the initial phase of sepsis. The amino acid leucine has shown to be particularly anabolic in performance sports, but little is known about its potential beneficial effects during acute illness. Leucine is a powerful activator of muscle protein synthesis and it seems that protein supplements with the highest leucine content elicit a greater increase in protein synthesis than those with a smaller fraction of leucine. The protein supplements used most in hospitals contain casein derived protein, which has a much lower leucine content than the whey protein compounds typically used in performance sports. This study compares three different protein supplements.The study is an open, randomized crossover trial. Laboratory technicians, test subjects and investigators will be blinded. Interventions: I. LPS (1 ng/kg as bolus) + 36 h fasting + 36 h bedrest + Casein (9% leucine) II. LPS (1 ng/kg as bolus) + 36 h fasting + 36 h bedrest + Whey (11% leucine) III. LPS (1 ng/kg as bolus) + 36 h fasting + 36 h bedrest + Leucine-enriched whey (16% leucine) The test objects will be given 0,6 g protein/kg, 1/3 as a bolus and 2/3 as sipping over a period of 3,5 hour. Muscle metabolism will be investigated by phenylalanine tracer using the forearm model and total protein metabolism using a carbamide tracer. Through muscle biopsies intracellular signalling pathways will be investigated.

Interventions*: I. LPS (1 ng/kg as bolus) + 36 h fasting + 36 h bedrest + Casein II. LPS (1 ng/kg as bolus) + 36 h fasting + 36 h bedrest + Whey III. LPS (1 ng/kg as bolus) + 36 h fasting + 36 h bedrest + Leucine-enriched whey * LPS will be administered on study day 1 and measurements of metabolism will be performed on study day 2 where we see the secondary effects of acute inflammation. The patient will stay at the hospital over night to ensure continues fast and bedrest. The beverages will be isocaloric and with the same total protein content. The basal period will be 2,5 hour with infusion of tracer. Hereafter a total amount of 0,6 g protein/kg bodyweight will be orally administered, 1/3 as a bolus and 2/3 as sipping over 3,5 hours. Muscle biopsies and blodsampels will be collected during both the basal and the sipping period.

The three different protein supplements will be fabricated with the same taste, colour and weight. They will be named "A", "B" and "C" and the investigator will not know which protein is which until all data has been collected and analysed.

"LPS + 36 hour fast and bedrest" + Casein (9% leucine) - 0.6 g protein/kg bodyweight, 1/3 as bolus and 2/3 as sipping.

"LPS + 36 hour fast and bedrest" + Whey (11% leucine) - 0.6 g protein/kg bodyweight, 1/3 as bolus and 2/3 as sipping

"LPS + 36 hour fast and bedrest" + Leucine-enriched whey (16% leucine) - 0.6 g protein/kg bodyweight, 1/3 as bolus and 2/3 as sipping

Changes of muscle phenylalanine net balance (= arterio(phe conc)-venous(phe conc) x flow) from baseline to 3.5 hours after intervention using the forearm model

Change in whole body protein metabolism measured by a combination of phenylalanine- and tyrosine tracer

Changes in whole body protein synthesis rates (umol/kg/h), breakdown rates (umol/kg/h), phenylalanine to tyrosine conversion rates (umol/kg/h) and net balance (umol/kg/h)

Using indirect calorimetry for 15 min for measuring glucose- (mg/kg/min), fat- (mg/kg/min) and protein oxidation (mg/kg/min)

changes from baseline to 3.5 hours after intervention in Ra(phe)=breakdown (umol/kg/h) and Rd(phe)=synthesis rate (umol/kg/h)

symptom score (from 0-5) for nausea, back pain, muscle pain, headache and chills. 0=no symptoms, 5=severe symptoms.

Inclusion Criteria: Healthy Male Age between 20-40 BMI between 20-30 Normal health examination and blood samples Written informed consent Exclusion Criteria: Immobilisation of an extremity, unless a doctor has declared it fully rehabilitated. Allergy against lidocain or latex. The use of anabolic steroids Disease like: Diabetes, epilepsia, infection, cardiovascular disease.

Mose M, Moller N, Jessen N, Mikkelsen UR, Christensen B, Rakvaag E, Hartmann B, Holst JJ, Jorgensen JOL, Rittig N. beta-Lactoglobulin Is Insulinotropic Compared with Casein and Whey Protein Ingestion during Catabolic Conditions in Men in a Double-Blinded Randomized Crossover Trial. J Nutr. 2021 Jun 1;151(6):1462-1472. doi: 10.1093/jn/nxab010.