A standardised static in vitro digestion method suitable for food – an international consensus

Abstract

Simulated gastro-intestinal digestion is widely employed in many fields of food and nutritional sciences, as conducting human trials are often costly, resource intensive, and ethically disputable. As a consequence, in\nvitro alternatives that determine endpoints such as the bioaccessibility of nutrients and non-nutrients or the\ndigestibility of macronutrients (e.g. lipids, proteins and carbohydrates) are used for screening and building\nnew hypotheses. Various digestion models have been proposed, often impeding the possibility to compare\nresults across research teams. For example, a large variety of enzymes from different sources such as of\nporcine, rabbit or human origin have been used, differing in their activity and characterization. Differences in\npH, mineral type, ionic strength and digestion time, which alter enzyme activity and other phenomena, may\nalso considerably alter results. Other parameters such as the presence of phospholipids, individual enzymes\nsuch as gastric lipase and digestive emulsifiers vs. their mixtures (e.g. pancreatin and bile salts), and the ratio\nof food bolus to digestive fluids, have also been discussed at length. In the present consensus paper, within\nthe COST Infogest network, we propose a general standardised and practical static digestion method based\non physiologically relevant conditions that can be applied for various endpoints, which may be amended to\naccommodate further specific requirements. A frameset of parameters including the oral, gastric and small\nintestinal digestion are outlined and their relevance discussed in relation to available in vivo data and\nenzymes. This consensus paper will give a detailed protocol and a line-by-line, guidance, recommendations\nand justifications but also limitation of the proposed model. This harmonised static, in vitro digestion method\nfor food should aid the production of more comparable data in the future.