A comprehensive review on in vitro digestion of infant formula

- Digestion of macronutrients in infants occurs in gastric and intestinal phases.
- In vitro models available for infant gastrointestinal digestibility study.
- Human and infant GI system differs in the availability of some digestive enzymes, their concentration and gastric pH.
- Infant formula and breast milk differ in their composition.

Although mothers' milk is the best food for babies, infant formula has become an alternative when breastfeeding is not possible or inadequate for babies. To design a proper formula for babies, understanding digestibility of macronutrients and their bio-accessibility in the gastrointestinal tract is essential. In vivo gastrointestinal studies on human infants are restricted by ethical constraint, cost issues, and intensive resource. However, in vitro models offer many advantages with low cost, easy sampling accessibility and no ethical issues. This article aims at reviewing the main aspects of the infant physiological gastrointestinal tract and providing an insight on recent in vitro research on infant formula.