Effect of Microbial Protease Supplementation on Postprandial Amino Acid Levels

Dietary protein is digested in the stomach and intestines to smaller peptides and 20 individual amino acids which, when absorbed by the gut into circulation and taken up by skeletal muscle, help stimulate muscle protein synthesis (MPS). Amino acids also provide the building blocks for muscle proteins that contribute to lean mass gains and increased strength following resistance exercise. Therefore, strategies to efficiently maximize amino acid exposure without overconsumption are warranted.

Oral enzyme supplementation is a candidate approach to optimize amino acid absorption from dietary protein and protein supplements. Microbial proteases, approved for dietary supplement use, can theoretically speed up the conversion of protein and peptides to amino acids. Protease supplements have been marketed to promote muscle strength by optimizing amino acid absorption, however the clinical evidence is limited. This work will support that ingestion of protease supplements with a meal can allow individuals to more efficiently increase amino acid levels from a given amount of dietary protein.


Eligibility Criteria:
Inclusion Criteria:

* Aged between 20 - 50 years
* Body mass index = 18.0-29.9 kg∙m-2

Exclusion Criteria:

* Age outside of range (20 - 50 y)
* Pregnancy
* Subject states they regularly consume probiotic supplements and are unwilling to stop at least one week prior to screening and throughout the study (Supplemental probiotics may include standalone probiotic supplements, vitamins with probiotics, and any foods supplemented with probiotics)
* Subject states they regularly consume supplemental enzymes and are unwilling to stop at least one week prior to screening and throughout the study (Supplemental enzymes may include standalone enzyme supplements, probiotic supplements with enzymes, and any medications containing enzymes)
* Abnormality or obstruction of the gastrointestinal tract precluding swallowing (e.g. dysphagia) and digestion (e.g., known intestinal malabsorption, celiac disease, inflammatory bowel disease, chronic pancreatitis, steatorrhea)
* Diabetes (fasting glucose ≥ 126 mg/dL)
* Active malignant disease, except basal or squamous cell skin carcinoma or carcinoma in situ of the uterine cervix
* Liver failure (decompensated chronic liver disease)
* History of a significant cardiovascular event (e.g., myocardial infarction, heart failure, or stroke) ≤ 3 months prior to the screening visit
* Subject reports having undergone major surgery less than 6 weeks prior to enrollment in the study, or subject has planned inpatient surgery requiring 2 or more days of hospitalization during the entire study
* Currently being prescribed (by primary care physician or other health professional) medication or using an over the counter product that in the opinion of the study physician will have an effect on food digestion or nutrient absorption during the study (e.g., prescription orlistat \[Xenical\], over the counter orlistat \[Alli\])
* Alcohol intake an average of 3 or more servings per day (a serving defined as 4 oz wine, 12 oz beer, 1 oz spirits)
* Subject is deemed unsuitable for study based upon study physician assessment
* Irregular menstrual cycles
* Participation in other ongoing research that interferes with this study (e.g., conflicting diet, activity interventions, etc.)
* Any hospitalization or surgery for a metabolic, cardiovascular, or neuromusculoskeletal complication within the past year
* Allergy or hypersensitivity to latex or adhesives (bandages, medical tape, etc.)
* Chronic or frequent dizziness/fainting, and arm or leg weakness/numbness
* Mental Illness
* Hepatorenal, cardiovascular musculoskeletal, autoimmune, or neurological disease or disorder
* Consumption of thyroid, androgenic, or other medications known to affect endocrine function
* Consumption of medications known to affect protein metabolism (e.g., prescription-strength corticosteroids, non-steroidal anti-inflammatories, or acne medication)
* Unwillingness to comply with study procedures
* Weight unstable (variation \>5% of bodyweight in last 6 months)
* Current or previous tobacco or marijuana use within the last 6 months