title: Suitability of 3-point versus 7-point postprandial retinyl palmitate AUC in human bioavailability studies.
abstract: BACKGROUND
  Bioavailability is a critical feature in the assessment of the role of micronutrients in human health. Although postprandial behaviour does not predict long-term responses and acute responses, it is accepted that the study of triglyceride-rich lipoprotein fractions reflects newly absorbed lipids from recent meals.
  
  
  OBJECTIVE
  To assess the predictive value of a 3-point versus 7-point post-prandial response (area under the curve) in nutrient bioavailability studies in humans.
  
  
  METHODS
  We used results from a human bioavailability study (n = 19) that consisted of a single-dose pharmacokinetic assay involving three types of commercially available vitamin A and E fortified milk.
  
  
  RESULTS
  Correlation coefficients between 3-point AUC (AUCp, predictive) versus 7-point AUC (AUCc, conventional) ranged between r = 0.81 (P < 0.001) for vitamin A-fortified skim milk and r = 0.95 (P < 0.001) for whole milk. Bland-Altman representations showed a good agreement between the two methods with 95% of the differences within the concordance limits. More than 90% of the subjects were correctly classified in the same or adjacent quartiles and he calculated relative absorption of vitamin A from the foods was, on average, <5% lower using the AUCp compared to that estimated using AUCc.
  
  
  CONCLUSIONS
  The use of the 3-point approach may be a reliable alternative to assess the relative postprandial lipid response in human bioavailability studies. Nevertheless, since this approach has been studied considering one nutrient (i.e. preformed vitamin A) and one type of food (i.e. milk), its applicability to other nutrients and foods should be tested.
authors.affiliation: Unidad de Vitaminas, Servicio de Bioquímica Clínica, Hospital Universitario Puerta de Hierro, 28035, Madrid, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Herrero-Barbudo
authors.forename: Fernando
authors.initials: F
authors.lastname: Granado-Lorencio
authors.forename: Begoña
authors.initials: B
authors.lastname: Olmedilla-Alonso
mesh_terms: D000328:Adult; D000818:Animals; D019540:Area Under Curve; D001682:Biological Availability; D018592:Cross-Over Studies; D004041:Dietary Fats / Q000494:pharmacology*; D004224:Diterpenes; D005260:Female; D005527:Food, Fortified; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects*; D008297:Male; D008892:Milk / Q000737:chemistry; D019518:Postprandial Period / Q000187:drug effects; D011237:Predictive Value of Tests; D000084562:Retinyl Esters; D014280:Triglycerides / Q000737:chemistry; D014801:Vitamin A / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics*; D014810:Vitamin E / Q000493:pharmacokinetics*
chemical_list: D004041:Dietary Fats; D004224:Diterpenes; D000084562:Retinyl Esters; D014280:Triglycerides; D014801:Vitamin A; D014810:Vitamin E; C014794:retinol palmitate