The Effects of a Microbial Enzyme Mixture on Macronutrient Hydrolysis in a Static Simulation of Oro-Gastric Digestion That Models Human Digestive Senescence

Abstract

Observational studies have shown that human digestive function declines naturally with age. Oral enzyme supplementation is a candidate strategy to enhance macronutrient digestion in older adults. The objective of this study was to test the effects of a mixture of six microbial enzyme preparations (ENZ) on nutrient bioaccessibility from a mixed meal in an in vitro model of digestive senescence. The mixed meal included chicken meat, peas, and potatoes. The INFOGEST 2.0 static simulation of oro-gastric digestion was used to model human digestive physiology along with a consensus protocol to model aging. Analytical testing of gastric digesta included measurements of free amino nitrogen (FAN), amino acid (AA), fatty acid (FA), glycerol, maltose, and glucose concentrations. Peptide distribution profiles were evaluated by size exclusion chromatography (SEC) and gel electrophoresis. After simulating digestion of the mixed meal, all nutrient bioaccessibility outcomes compared to pepsin-only controls, except glycerol, were further enhanced by ENZ in the aging condition compared to the standard condition (FAN: 77.1 vs. 39.3%; essential AA: 100.4 vs. 57.6%; total FA: 12.8- vs. 8.0-fold; maltose: 142.1 vs. 0.7%). SEC confirmed ENZ’s proteolytic capacity to generate more lower molecular weight peptides and free AAs in standard and aging conditions compared to pepsin alone. Gel electrophoresis confirmed proteolytic enhancement with ENZ. These data showcase ENZ’s hydrolytic activity toward macronutrients and suggest ENZ’s capacity to compensate for reduced pepsin activity in an aging-adapted oro-gastric digestion simulation.

Keywords

• aging
• amylase
• dietary protein
• digestive enzyme
• INFOGEST
• lipase