Effects of Ingesting Multiple Boluses of Collagen on Muscle & Skin Connective Protein Synthesis in Vivo in Humans

Collagen Digestion and Amino Acid Absorption Kinetics and the Effect on Muscle & Skin

Rationale: Collagen protein is the central structural component of extracellular connective tissues within skeletal muscle, bone, cartilage and skin. Dietary collagen peptides are a promising protein source to deliver the specific amino acid precursors required to support an increase in connective tissue protein synthesis across several tissues (e.g. muscle, skin). However, the digestion and absorption kinetics of multiple boluses of collagen peptides and the subsequent impact on muscle and skin connective tissue protein synthesis rates have not yet been assessed in vivo in humans.

Objective: To assess the impact of ingestion of multiple boluses of collagen peptides on muscle connective and skin protein synthesis in vivo in humans.

Study design: Double-blind, parallel-group, placebo-controlled intervention study.

Study population: 20 healthy young males, aged 18-35 years.

Intervention : Participants will perform unilateral resistance exercise followed by the ingestion of either 100 g of collagen peptides (in boluses) or a non-caloric placebo (flavoured water) drinks, while all drinks will contain vitamin C. Continuous intravenous stable isotope amino acid tracer infusions will be applied, plasma, skin and muscle samples will be collected in order to assess protein synthesis rates in skin and muscle tissue.

Main study parameters/endpoints: Primary study parameters are muscle connective protein synthesis rates. Secondary study parameters are skin and myofibrillar protein synthesis rates, plasma amino acid concentrations and body composition.

Inclusion Criteria:

• Aged between 18-35 years
• Male
• Healthy, recreationally active (participating in recreational sports activities ≥ 1 and ≤ 6 h per week, with a maximum of 2 h resistance-type exercise)
• 18.5 ≤ BMI ≤ 30 kg/m2
• No physical limitations (i.e. able to perform all activities associated with daily living in an independent manner).

Exclusion Criteria:

• Female
• Smoking
• Musculoskeletal disorders
• Metabolic disorders
• Use of any medications known to affect protein metabolism (i.e. corticosteroids, non-steroidal anti-inflammatories, or prescribed acne medications).
• Chronic use of gastric acid suppressing medication or anti-coagulants
• Unstable weight over the last three months
• Diagnosed GI tract disorders or diseases
• Blood donation in the past 2 months