Interface chemistry affected the digestion fate of ketogenic diet based on medium- and long-chain triglycerides

Abstract

Ketogenic diet, characterized by high fat and low carbohydrate content, is gradually becoming a new perspective in the human diet; however, the mechanism of digestion of ketogenic diet remains unknown. In this study, we explored the oil-water interface to elucidate the digestion of a ketogenic diet based on typical representative medium- and long-chain triglycerides. The free fatty acids (FFAs) release indicated that glycerol trioctanoate with a shorter carbon chain (FFA = 920.55 ± 10.17 μmol) was significantly more digestible than glycerol tripalmitate (851.36 ± 9.48 μmol) and glycerol tristearate (805.81 ± 10.03 μmol). Particle size analysis revealed that the length of the carbon chain increased the size of triglycerides, resulting in a decreased contact area with lipase. The interfacial phenomenon indicated that the longer the carbon chain of triglycerides, the greater the reduction in binding capacity with salt ions in the digestive solution. Fluorescence spectroscopy analysis showed that the length of the carbon chain induced the displacement of the lipase peak, suggesting that the carbon chain length could alter the structure of lipase. Molecular dynamics simulation showed that the longer the carbon chain of triglycerides, the easier it was to loosen the structure of lipase. Bond energy analysis showed that the carbon chain length of triglycerides was positively correlated with the bond energy strength of the ester bonding. In conclusion, this study emphasizes that the ketogenic diet should primarily consist of shorter carbon chain triglycerides because carbon chain length can alter the digestion of triglycerides. This provides a new perspective on the quest for more effective ketogenic diet, in line with the current view of healthy diet.

Keywords: Bond energy; Carbon chain length; Digestibility; Ketogenic diet; Lipase; Molecular dynamics simulation; Triglycerides.