ABSTRACT
The physiological definition of resistant starch, which is largely adopted, implies the analytical methods of resistant starch in foods to be validated with in vivo data obtained from healthy individuals. The intubation technique is the only one to be applicable to healthy volunteers. The main drawback of the method is the presence of the tube along the small intestine (direct collection of ileal content) and its possible influence on the transit. Several other methods are available to assess physiologically resistant starch in vivo. Resistant starch can be quantified directly, by collecting ileal samples in human ileostomates or animals, or indirectly by estimating the amount of starch fermented in the colon. The ileostomy model allows direct and quantitative determination of small bowel excretion, provided the bacterial degradation of the effluent can be minimized. Hydrogen breath test is also used to quantify malabsorption of starch. It is rapid and simple but indirect and consequently semiquantitative. Rats (antibiotic treated, germ-free or colectomized) and pigs (ileum cannulated or with ileorectal anastomosis) are considered as useful models for estimating starch digestion in humans. However
Animal models Humans Pigs Indirect
Ileum cannulated H2 Breath test
Anastomosis Direct
Rats Ileostomy model
Antibiotic treated Intubation of healthy subjects
Germ-free Caecectomized
Colectomized
H2 excretion
it cannot be expected from these animal models to predict accurate values of ileal digestibility.
