Monitoring food digestion with magnetic resonance techniques

This review outlines the current use of magnetic resonance (MR) techniques to study digestion and highlights their potential for providing markers of digestive processes like texture changes and nutrient breakdown. In vivo digestion research can be challenging due to practical constraints and biological complexity. Therefore, digestion is primarily studied using in vitro models. These would benefit from further in vivo validation. Nuclear magnetic resonance (NMR) is widely used to characterize food systems. Magnetic resonance imaging (MRI) is a related technique that can be used to study both in vitro model systems and in vivo gastro-intestinal processes. MRI allows visualisation and quantification of gastric processes like gastric emptying and coagulation. Both MRI and NMR scan sequences can be configured to be sensitive to different aspects of gastric or intestinal contents. For example, magnetization transfer (MT) and chemical exchange saturation transfer (CEST) can detect proton (H+) exchange between water and proteins. MRI techniques have the potential to provide molecular-level and quantitative information on in vivo gastric (protein) digestion. This requires careful validation in order to understand what these MR markers of digestion mean in a specific digestion context. Combined with other measures they can be used to validate and inform in vitro digestion models. This may bridge the gap between in vitro and in vivo digestion research and can aid the optimization of food properties for different applications in health and disease.