The Influence of Enzymatically Synthesized Medium- and Long-Chain Triacylglycerols on Lipid Digestion Characteristics: Insights from In Vitro and In Vivo Models.

Age-related declines in gastrointestinal function increase the malnutrition risk and highlight the need for lipid formulations with digestive and metabolic characteristics suited to older populations. In this study, a structurally characterized medium- and long-chain triacylglycerol (MLCT) prepared by enzymatic transesterification was compared with a compositionally equivalent physical blend (PB) using a simulated in vitro gastrointestinal digestion model for the elderly and an in vivo indirect calorimetry in adult mice. MLCT exhibited a more gradual fatty acid release pattern and 33-44% lower lipolysis during the initial gastrointestinal stages than PB without affecting final hydrolysis, and it significantly improved polyunsaturated fatty acid bioaccessibility. In mice, MLCT administration was associated with comparatively gradual changes in whole-body energy expenditure and respiratory gas exchange among the lipid treatments. These findings indicate that the TAG structure influences digestive kinetics and acute whole-body metabolic responses, supporting the further evaluation of MLCT for nutritional applications involving age-related digestive decline.