Healthy Volunteers
Conditions
Keywords
Purple bacteria, Amino acid bioavailability, Protein absorption, Functional foods, Postprandial metabolism, Dairy product, Healthy adults
Brief summary
This interventional clinical study aims to evaluate the bioavailability of amino acids derived from purple bacteria in healthy adults. Participants will consume either a protein-enriched dairy product or a protein-enriched dairy product containing purple bacteria during two separate test periods in a randomized cross-over design. Blood amino acid concentrations will be measured over a 4-hour postprandial period to assess amino acid absorption and bioavailability. Additional biological samples including saliva, exhaled air, and feces will be collected to evaluate gastrointestinal hormones, volatilome profiles, and related metabolic responses.
Detailed description
Purple bacteria are recognized for their high-quality protein content, including essential amino acids, as well as their vitamin and carotenoid composition. However, limited data are available regarding the bioavailability of amino acids derived from purple bacteria in humans. This randomized, open-label, cross-over study will enroll approximately 12 healthy adult participants in Belgium. Each participant will receive two dairy-based formulations in randomized order: Control formulation: protein-enriched dairy product. Test formulation: protein-enriched dairy product containing purple bacteria. The two intervention periods will be separated by a washout period of at least one week. Participants will undergo one screening visit and two test visits. During each test visit, serial blood samples will be collected over 240 minutes following ingestion of the assigned formulation to determine plasma amino acid concentrations. Additional saliva, exhaled air, and fecal samples will also be collected. The primary objective is to determine whether amino acids present in purple bacteria are better absorbed than amino acids from other protein sources.
Interventions
DIETARY_SUPPLEMENTPurple Bacteria-Enriched Dairy Product
Approximately 50 g of purple bacteria incorporated into approximately 110 g of a protein-enriched dairy product.
OTHERProtein-Enriched Dairy Product
160 g of protein-enriched dairy product.
Sponsors
Université Catholique de Louvain
University of Mons
University of Liege
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Intervention model description
Participants will receive both study formulations in randomized order over two intervention periods separated by a washout period of at least one week.
Eligibility
Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
* Adults aged 18 to 50 years * Body mass index between 18 and 30 kg/m² * Healthy participants * Non-smokers * Women of childbearing potential using effective contraception * Able to understand and speak French * Willing and able to comply with study procedures
Exclusion criteria
* Pregnancy or breastfeeding * Use of medications or dietary supplements incompatible with study participation * Any medical condition considered by the investigator to interfere with study participation or interpretation of results * Vegan or vegetarian diets
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in postprandial plasma essential amino acid concentrations (µmol/L) | Throughout the entire study, approxiamtely during 1 month | Plasma concentrations of essential amino acids (including leucine, isoleucine, valine, lysine, threonine, phenylalanine, methionine, tryptophan, and histidine) will be measured using LC-MS/MS at baseline and at multiple postprandial time points following ingestion of control and test formulations. Results will be reported as incremental area under the curve (iAUC, µmol/L·h) over the postprandial period. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in exhaled volatile organic compounds (VOCs) profile (relative abundance, arbitrary units) | Throughout the entire study, approxiamtely during 1 month | Exhaled air samples will be analyzed using gas chromatography-mass spectrometry (GC-MS). Specific VOCs will be quantified and reported as relative abundance (arbitrary units) and/or multivariate profile changes (e.g., PCA scores) comparing test vs control formulations. |
| Change in salivary gastrointestinal hormone concentrations (pg/mL) | Throughout the entire study, approxiamtely during 1 month | Salivary concentrations of gastrointestinal hormones (e.g., ghrelin, GLP-1, PYY) will be measured using immunoassays. Results will be expressed as change from baseline and iAUC (pg/mL·h) over the postprandial period. |
| Gastrointestinal symptom severity score assessed using a 5-point Likert scale (0-4) | Throughout the entire study, approxiamtely during 1 month | Gastrointestinal tolerance will be assessed using a standardized symptom questionnaire evaluating the severity of gastrointestinal symptoms (including bloating, abdominal pain, flatulence, nausea, and diarrhea). Each symptom will be rated using a 5-point Likert scale, defined as: 0 = not at all 1. = slightly 2. = moderately 3. = severely 4. = very severely Results will be reported as: mean gastrointestinal symptom score (average across symptoms) and/or total symptom score (sum of all items; higher scores indicate worse symptoms) and change from baseline over the postprandial period following ingestion of study formulations. |
| Number of participants with at least one adverse event | Throughout the entire study, approxiamtely during 1 month | Adverse events will be collected throughout the study period and reported as the number and proportion of participants experiencing at least one adverse event, by condition. |
Countries
Belgium
Contacts
PRINCIPAL_INVESTIGATORSylvie Copine, Dr
Université Catholique de Louvain
PRINCIPAL_INVESTIGATORLaurent Simar, Dr
Université Catholique de Louvain
Outcome results
None listed