title: Folate catabolites in spot urine as non-invasive biomarkers of folate status during habitual intake and folic acid supplementation.
abstract: BACKGROUND
  Folate status, as reflected by red blood cell (RCF) and plasma folates (PF), is related to health and disease risk. Folate degradation products para-aminobenzoylglutamate (pABG) and para-acetamidobenzoylglutamate (apABG) in 24 hour urine have recently been shown to correlate with blood folate.
  
  
  OBJECTIVE
  Since blood sampling and collection of 24 hour urine are cumbersome, we investigated whether the determination of urinary folate catabolites in fasted spot urine is a suitable non-invasive biomarker for folate status in subjects before and during folic acid supplementation.
  
  
  METHODS
  Immediate effects of oral folic acid bolus intake on urinary folate catabolites were assessed in a short-term pre-study. In the main study we included 53 healthy men. Of these, 29 were selected for a 12 week folic acid supplementation (400 µg). Blood, 24 hour and spot urine were collected at baseline and after 6 and 12 weeks and PF, RCF, urinary apABG and pABG were determined.
  
  
  RESULTS
  Intake of a 400 µg folic acid bolus resulted in immediate increase of urinary catabolites. In the main study pABG and apABG concentrations in spot urine correlated well with their excretion in 24 hour urine. In healthy men consuming habitual diet, pABG showed closer correlation with PF (rs = 0.676) and RCF (rs = 0.649) than apABG (rs = 0.264, ns and 0.543). Supplementation led to significantly increased folate in plasma and red cells as well as elevated urinary folate catabolites, while only pABG correlated significantly with PF (rs = 0.574) after 12 weeks.
  
  
  CONCLUSIONS
  Quantification of folate catabolites in fasted spot urine seems suitable as a non-invasive alternative to blood or 24 hour urine analysis for evaluation of folate status in populations consuming habitual diet. In non-steady-state conditions (folic acid supplementation) correlations between folate marker (RCF, PF, urinary catabolites) decrease due to differing kinetics.
authors: Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital Medical Center of Ludwig Maximilians University, Munich, Germany.
authors: Mareile
authors: M
authors: Niesser
authors: Hans
authors: H
authors: Demmelmair
authors: Thea
authors: T
authors: Weith
authors: Diego
authors: D
authors: Moretti
authors: Astrid
authors: A
authors: Rauh-Pfeiffer
authors: Marola
authors: M
authors: van Lipzig
authors: Wouter
authors: W
authors: Vaes
authors: Berthold
authors: B
authors: Koletzko
authors: Wolfgang
authors: W
authors: Peissner
mesh_terms: D000328:Adult; D019587:Dietary Supplements / Q000032:analysis; D005492:Folic Acid / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism* / Q000652:urine*; D005971:Glutamates / Q000097:blood / Q000378:metabolism / Q000652:urine; D006710:Homocysteine / Q000097:blood / Q000652:urine; D006801:Humans; D008297:Male; D016482:Urinalysis; D014805:Vitamin B 12 / Q000097:blood / Q000652:urine; D025101:Vitamin B 6 / Q000097:blood / Q000652:urine; D055815:Young Adult
chemical_list: D005971:Glutamates; D006710:Homocysteine; D025101:Vitamin B 6; D005492:Folic Acid; D014805:Vitamin B 12