A review, led by Dr. Julian McClements from the University of Massachusetts, suggests the need for better correlations between in vitro and in vivo research models of digestion.
Further research into modelling techniques is needed before industry can accurately model the effects of novel foods and supplements, he added
The authors stated that the new study “enhances the understanding of invitro digestion models and provides indications for the development of improved in vitro digestion models for foods.”
In vitro digestion models – Latin for ‘within the glass’ – are commonly used to study the structural changes, digestibility, and release of food under simulated digestive conditions. Whilst in vivo methods – Latin for ‘within the living’ –, provide more precise results, but are time consuming and costly, due to the involvement of human or animal trials.
The outcomes of in vitro models are regularly different to those using in vivo models, due to difficulties in simulating the highly complicated physicochemical and physiological actions occurring in animal and human digestion.
As investigating the structure of food, and food based delivery systems for the encapsulation, protection, and release of bioactive ingredients becomes more important, the discrepancies between the two research models could cause even greater problems.
The new study reviews current trends in the development and use of in vitro digestion models for foods, and provides information that could be used to develop improved modelling techniques.
The authors reviewed over 80 in vitro studies using digestion models performed over the last 10 years.
Major differences in these studies reflected the food component being analyzed, the nature of the food matrix, and the sophistication of the in vitro digestion model used.
Certain methods were found to be similar across all studies, with all the digestion models surveyed using a digestion temperature was 37 °C, and many studies using a digestion time of two hours.
The study found that the commonest food samples tested were plants, meats, fish, dairy, and emulsion-based foods. The most frequently used biological molecules included in the digestion models were digestive enzymes (pancreatin, pepsin, trypsin, chymotrypsin, peptidase, α-amylase, and lipase), bile salts, and mucin.
The researchers suggest in vitro models could be validated by comparing bioaccessibility data with in vivo human or animal data, but propose that validation of in vitro models for consumer products would be difficult because there is limited human in vivo data for consumer products.
The researchers claim that in order to truly test the efficacy of new foods and delivery systems, accurate models simulating the complex physiological and biochemical interactions of human digestion must be available.
Finding accurate correlations between in vitro and in vivo models are important steps towards better development of food and nutritional ingredients, they added.
“There is clearly an urgent need for more research into in vitro-in vivo correlations with well-defined systems, so that more realistic in vitro models can be developed to screen the bioavailability and digestibility of foods,” stated the researchers.
“Further research is needed to analyze the advantages and disadvantages of in vitro digestion models for different food samples,” they concluded.
Source: Food Chemistry
Published online ahead of print, doi: 10.1016/j.foodchem.2010.08.036
“In vitro Human Digestion Models for Food Applications”
Authors: S.J. Hur, B.O. Lim, E.A Decker, D.J. McClements