Document ID: chunk:federal_register_of_legislation:F2016C00156:body:0:p18
Version: federal_register_of_legislation:F2016C00156
Segment Type: other
Provision Reference: 
Character Range: 47853–50750

collection of urine and faeces for the equivalent period. It is acceptable for this method to use animal or human subjects, although coprophagy must have been eliminated during rat studies. This method is best suited to measurements of food ingredients that are not fermented in the large intestine and which do not produce gas. However, it is acceptable to use this method for food ingredients that are fermented in the large intestine if it is combined with other methods that measure the percentage of the food ingredient that is fermented (or gas production directly).

    (c)  isotopic tracer methods – FE, UE, upper intestinal absorption, large intestinal fermentation
    These methods involve the use of isotopically labelled substrates (e.g. 13C or 14C) and measure the percentage of the given dose that is recovered in metabolised form (e.g. in CO2 in breath), in unmetabolised (urine) form, or undigested (faeces) form. It is acceptable to combine this method with other techniques to provide adjunct information on intestinal absorption (e.g. analysis of blood glucose fluctuations or other metabolites) and fermentation (breath hydrogen). It is also acceptable to use studies in germ free animals to provide comparative data that calculates the amount of the food ingredient fermented in the large intestine.

(d)  breath hydrogen test – GaE, large intestinal fermentation
    The breath hydrogen response is a reflection of the nutrients fermented in the large intestine, and is also suitable for use in estimating GaE. A common form of the test is to measure basal breath H2 obtained after a dose of lactulose compared with the breath H2 after a dose of the test food ingredient.

    (e)  ileal intubation and ileostomy effluent – small intestinal absorption, large intestinal fermentation
    Ileal intubation involves the insertion of a nasogastric tube and sampling the digestive matter in the terminal ileum. Ileostomy studies involve subjects who have had. their large bowel surgically removed and in whom digestive excreta (from the end of the small bowel) is collected in a plastic bag. The results of these studies may not be quantitatively representative of normal physiologic status, but they are able to provide a direct estimate of upper intestine absorption by measuring small bowel content at the terminal end of the ileum. Combined with faecal excretion, ileal intubation is also able to provide an indirect measure of the proportion of the food ingredient that reaches the large intestine and is fermented.

     B.4 Information on other factors. that affect the calculation of the energy factor

The application must include information on the following matters. where relevant:
    (a) justification for and limitations of the evidence and methods used to substantiate the individual components of the energy factor equation
    (b) whether the GE of the food