title: The effect of pre- and probiotics on the colonic ammonia metabolism in humans as measured by lactose-[¹⁵N₂]ureide.
abstract: BACKGROUND
  The evaluation of ammonia detoxification by pre- and probiotics by means of colonic lactose-[(15)N(2)]ureide ((15)N-LU) degradation is of great interest both scientifically and in terms of nutrition physiology.
  
  
  OBJECTIVE
  Pre- and probiotics were supplemented in healthy adults to evaluate the effect of the ammonia metabolism in the human colon by means of (15)N-LU.
  
  
  METHODS
  A total of 14 participants aged 20-28 years daily received a regular diet either without (no treatment) or with supplementation of 30 g fibre of potatoes (FPs), 30 g wrinkle pea starch (WPS, resistant starch content: 12 and 70%, respectively) and 375 g Lactobacillus acidophilus (LC1) yoghurt, over a 10-day period in a randomised order. After 1 week, 5.7 mg/kg body weight (15)N-LU was administered together with breakfast. A venous blood sample was taken after 6 h. Urine and faeces were collected over a period of 48 and 72 h, respectively. The (15)N abundances were measured by isotope ratio mass spectrometry.
  
  
  RESULTS
  The mean renal (15)N-excretion differed significantly between the supplementation of FP and no treatment (32.5 versus 46.3%, P=0.034), FP and LC1 (32.5 versus 51.6%, P=0.001), and WPS and LC1 (38.5 versus 51.6%, P=0.048). The mean faecal (15)N-excretion amounted to 42.7% (no treatment), 59.7% (FP), 41.8% (WPS) and 44.0% (LC1). In comparison with no treatment, the urinary (15)NH(3)-enrichment was significantly decreased at 16 h after FP supplementation.
  
  
  CONCLUSIONS
  The prebiotic intake of FP and WPS lowered the colonic generation and the renal excretion of toxic (15)NH(3), respectively, when using (15)N-LU as a xenobiotic marker.
authors.affiliation: Research Laboratory Gastroenterology and Nutrition, Children's Hospital, University of Rostock, Rostock, Germany. klaus-dieter.wutzke@med.uni-rostock.de
authors.forename: K D
authors.initials: KD
authors.lastname: Wutzke
authors.forename: M
authors.initials: M
authors.lastname: Lotz
authors.forename: C
authors.initials: C
authors.lastname: Zipprich
mesh_terms: D000328:Adult; D000641:Ammonia / Q000378:metabolism*; D003106:Colon / Q000382:microbiology* / Q000502:physiology*; D005243:Feces / Q000737:chemistry; D005260:Female; D005516:Food Microbiology; D006801:Humans; D007779:Lactobacillus acidophilus / Q000378:metabolism; D007785:Lactose / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D008297:Male; D009587:Nitrogen Isotopes; D018532:Pisum sativum / Q000737:chemistry; D035281:Plant Tubers / Q000737:chemistry; D056692:Prebiotics; D019936:Probiotics / Q000378:metabolism*; D012639:Seeds / Q000737:chemistry; D011198:Solanum tuberosum / Q000737:chemistry; D013213:Starch / Q000008:administration & dosage / Q000378:metabolism; D014508:Urea / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D015014:Yogurt; D055815:Young Adult
chemical_list: D009587:Nitrogen Isotopes; D056692:Prebiotics; C121442:lactose ureide; D000641:Ammonia; D014508:Urea; D013213:Starch; D007785:Lactose