(P06-043-23) Gastric Casein Coagulation and Postprandial Amino Acid Absorption of Milk Is Affected by Mineral Composition: A Randomized Crossover Trial

Objectives: In vitro studies suggest that gastric casein coagulation and digestion of milk formula under simulated infant conditions are affected by casein micelle mineralisation. Casein micelle mineralisation may thus also impact overall digestion and absorption kinetics in vivo. This study therefore aimed to determine the effect of milk casein micelle mineralisation on milk protein digestion and absorption.

Methods: In a randomized cross-over study healthy males (n =15, age 30.9±13.8 years) were fed low or high casein micelle mineralization milk and underwent gastric magnetic resonance imaging (MRI) scans to determine gastric emptying (manual segmentation) and the degree of casein coagulation (image texture analysis). Blood samples were taken at baseline and up to 5 hours postprandially to determine amino acid absorption kinetics and changes in plasma insulin and glucose. Additionally, the contribution of whey and casein derived amino acids over time was determined.

Results: MRI analyses showed that gastric volume over time did not differ between treatments. However, the degree of casein coagulation was lower for low mineralisation milk. Postprandial plasma amino acid kinetics showed that peak levels of casein-dominant amino acids, such as proline, were significantly higher in the low casein mineralisation condition, whereas whey-dominant amino acids, such as leucine, did not differ. Plasma insulin responses were in line with an initial higher level of branched-chain amino acids in the low mineralisation condition although only valine was significantly different.

Conclusions: Mineral composition of milk can influence gastric coagulation with coherent effects on post prandial plasma amino acid kinetics and plasma insulin responses without impacting overall gastric emptying. 

Funding Sources: FrieslandCampina