Nutritional Strategies to Augment the Postprandial Muscle Protein Synthetic Response to the Ingestion of a Low Dose of Protein in Middle-aged Women

University of Illinois at Urbana-Champaign50 enrolled

Overview

Using stable isotope methodology, investigators will determine the postabsorptive and postprandial muscle protein synthetic response in 60 female adults (Age 50-79, BMI: \<30 kg/m2) immediately after an acute bout of resistance exercise. Participants will be divided in to 5 groups of twelve women (n=12). Each group will receive a different protein beverage or placebo to consume following the resistance exercise training. Group 1 will consume a beverage consisting of whey protein; group 2 will consume whey protein supplemented with additional leucine; group 3 will consume whey protein supplemented with additional leucine and hydrolyzed whey peptides; group 4 will consume whey protein supplemented with additional leucine and citrulline; group 5 will just consume water. During the testing, blood and muscle samples will be collected.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Enrollment

Conditions

Aging

Interventions

Eligibility

Sex: FEMALEMin age: 20 YearsMax age: 79 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * BMI \<30 kg/m2 * Healthy, sedentary * Either 20-30 years old or 50-79 years old Exclusion Criteria: * Tobacco use * Allergies to milk consumption * Unusually high protein consumption * Vegan diet * Allergies to antibiotics or xylocaine * Phenylketonuria (PKU) * Diagnosed GI tract diseases * Arthritic conditions * A history of neuromuscular problems * Heart disease * Metabolic disorders * -Liver, kidney, or urinary disease * Musculoskeletal problems * Autoimmune disease * Neurological disease * Previous participation in amino acid tracer studies * Predisposition to hypertrophic scarring or keloid formation * Individuals on any medications known to affect protein metabolism (i.e. corticosteroids, non-steroidal anti-inflammatories, or prescription strength acne medications). * Individuals using thyroid medications or other medications affecting endocrine function * Pregnancy * Contraindications for exercise * BMI ≥30 * supplements that influence protein metabolism (e.g omega 3 fish oils)

Outcomes

Primary Outcomes

The myofibrillar protein synthetic response to protein ingestion

Myofibrillar protein synthesis rates will be assessed during the postabsorptive period for 3 hr and during the 4 hr after the ingestion of the experimental beverages. This will allow us to assess the change from the postabsorptive to the postprandial period

Time frame: Postabsorptive for 3 hours, Postprandial for 4 hours hours

Secondary Outcomes

mTORC1 phosphorylation

Activation of anabolic signaling pathways will be assessed in the fasted state and at 2 and 4 hr after the ingestion of the experimental beverages.

Time frame: Baseline and at 2 and 4 hours after protein ingestion