title: Analysis of microsamples of human faeces: a non-invasive approach to study the bioavailability of fat-soluble bioactive compounds.
abstract: BACKGROUND
  Bioavailability is a critical feature in the assessment of the role of micronutrients in human health. Poorly bioavailable micronutrients like carotenoids may reach significant concentrations in the gastrointestinal tract where they may exert biological actions.
  
  
  OBJECTIVE
  We evaluated a simple collection protocol to determine vitamin A, E and carotenoids in microsamples of human faeces as a non-invasive approach for nutritional studies.
  
  
  METHODS
  Microsamples of human faeces were collected using a commercially available device, extracted and analysed on two LC systems. Suitability of the protocol was assessed by evaluating several factors including the effect of simulated colonic conditions and two nutritional scenarios with different dietary components, chemical forms, nutritional goals and target groups.
  
  
  RESULTS
  The protocol was reproducible and representative of a faeces sample. The major dietary and serum carotenoids, and several "unidentified" compounds (possibly metabolites) could be detected, and cis-/trans-β-carotene profile reflected dietary intervention. In faeces of neonates, free retinol, retinyl and α-tocopheryl acetate (from infant formula), long-chain fatty acid retinyl esters (from human milk), free γ-tocopherol and α-tocopherol could be detected.
  
  
  CONCLUSIONS
  Our results show that the analysis of vitamin A, E and carotenoids in microsamples of human faeces is a suitable, non-invasive approach that may provide relevant information regarding responsiveness, nutrient stability and metabolism and may help assess adequacy of chemical forms and delivery systems reaching the colon.
authors.affiliation: Grupo Metabolismo y Nutrición, IDIPHIM, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain.|Servicio de Bioquímica Clínica, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Hernandez-Alvarez
authors.affiliation: Grupo Metabolismo y Nutrición, IDIPHIM, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain.|Unidad de Vitaminas, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain.
authors.forename: B I
authors.initials: BI
authors.lastname: Pérez-Sacristán
authors.affiliation: Grupo Metabolismo y Nutrición, IDIPHIM, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain.|Servicio de Bioquímica Clínica, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain.|Unidad de Vitaminas, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Blanco-Navarro
authors.affiliation: Grupo Metabolismo y Nutrición, IDIPHIM, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain.|Servicio de Bioquímica Clínica, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Donoso-Navarro
authors.affiliation: Grupo Metabolismo y Nutrición, IDIPHIM, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain.|Servicio de Bioquímica Clínica, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain.
authors.forename: R A
authors.initials: RA
authors.lastname: Silvestre-Mardomingo
authors.affiliation: Grupo Metabolismo y Nutrición, IDIPHIM, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain. fgranado.hpth@salud.madrid.org.|Servicio de Bioquímica Clínica, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain. fgranado.hpth@salud.madrid.org.|Unidad de Vitaminas, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain. fgranado.hpth@salud.madrid.org.
authors.forename: F
authors.initials: F
authors.lastname: Granado-Lorencio
mesh_terms: D001682:Biological Availability; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D018977:Micronutrients / Q000097:blood / Q000493:pharmacokinetics*; D008875:Middle Aged; D014801:Vitamin A / Q000097:blood / Q000493:pharmacokinetics; D014810:Vitamin E / Q000097:blood / Q000493:pharmacokinetics; D024502:alpha-Tocopherol / Q000097:blood / Q000493:pharmacokinetics; D019207:beta Carotene / Q000097:blood / Q000493:pharmacokinetics
chemical_list: D018977:Micronutrients; D019207:beta Carotene; D014801:Vitamin A; D014810:Vitamin E; D024502:alpha-Tocopherol
keywords: Carotenoids; Human faeces; Vitamin A; Vitamin E