This research theme addresses the fate of dietary proteins in the body with a focus on digestion, absorption and other processes in the gastrointestinal tract. This will gain insights that will aid the selection of protein sources for the human diet, a matter that is particularly important for vulnerable populations that are at risk for protein malnutrition. The work carried out in this theme benefits from the close collaboration between the division of Human Nutrition and the department of Animal Nutrition.
Protein Quality & Digestibility
Protein nutritional quality has been identified as a critical topic by international authorities like the FAO. Protein quality is related to the capacity of food sources of protein to enable proper performance of body functions and processes associated to the supply of nitrogen and amino acids. The protein quality evaluation system considers the capacity of a protein source ingested at the level of the mean protein requirement. The latter is derived from nitrogen balance to meet indispensable amino acid needs.
The Digestible Indispensable Amino Acid Score (DIAAS) takes into account the bioavailability of the amino acids in the protein source by considering the specific ileal digestibility of each indispensable amino acid separately. The application of DIAAS comes with several methodological challenges related to the measurement of amino acid ileal digestibility, particularly in humans. We are experienced in measuring ileal digestibility in patients with an ileostoma and in pigs, animals that are very similar to humans in their gastrointestinal physiology. Moreover, we are working with the dual tracer approach to measure amino acid digestibility, a less invasive techniques that can also be applied to study digestion in vulnerable populations.
Proteins that escape digestion and absorption in the upper gastrointestinal tract are susceptible to metabolization by bacteria in the large intestine. Several metabolites are formed during protein fermentation, such as biogenic amines. Many of these metabolites have been associated with decreased gut health and diseases, such as inflammatory bowel diseases. Understanding the effect of protein source selection and its ileal digestibility on the potential fermentability and the formation of metabolites will provide valuable insights to improve gut health.