Evaluation of the Bioavailability of Amino Acids From Purple Bacteria

Evaluation of the Consumption of Fresh Purple Bacteria Biomass in Healthy Humans: Safety Test and Monitoring of Metabolism

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.

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.

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