Abstract
Resistant starch (RS) and Lactobacillus acidophilus yoghurt (LC1) were supplemented simultaneously in healthy adults to evaluate the effect on the urinary and faecal nitrogen and ammonia excretion by means of lactose-[15N2]ureide (15N-LU) degradation. Nineteen subjects received a regular daily diet either without or with supplementation of an RS-LC1-mixture composed of fibre of potatoes (RS type 1), wrinkle pea starch (RS type 2), and LC1 over a 20-day period in randomised order. Thereafter, 15N-LU was administered together with breakfast. Urine and faeces were collected over a period of 48 and 72 h, respectively. The 15N abundances were measured by isotope ratio mass spectrometry. The intake of the pre- and probiotic mixture composed of RS of type 1, type 2 and of LC1 significantly lowered the colonic generation and the renal excretion of toxic 15NH3 and functioned as an ammonia shift from urinary to faecal 15N excretion when using 15N-LU as a xenobiotic marker.