title: Characterisation with stable isotopes of the presence of a lag phase in the gastric emptying of liquids.
abstract: BACKGROUND
  Gastric emptying of non-nutrient liquids usually lacks the presence of an initial delay phase (lag phase), and so it has been considered to be monoexponential with an initial rapid phase followed by a slower emptying phase. However a lag phase in the gastric emptying of liquids can be found if there is a high caloric density in the liquid meal.
  
  
  OBJECTIVE
  To characterise with stable isotopes the presence of a lag phase in the gastric emptying of non-solid meals.
  
  
  METHODS
  Healthy volunteers ingested a low caloric liquid meal (345 KJ/ 200 mL) (LCLM), a high caloric liquid meal (1135 KJ/180 mL) (HCLM) or a semisolid meal (1403 KJ/500 mL) (SSM). Test meals were labelled with 13C-acetate. Breath samples were collected for 13CO2 measurement and data were fitted to a power exponential function.
  
  
  RESULTS
  Non-solid meals can have different behaviour related to the initial emptying. The presence of a lag phase in the gastric emptying of liquids was not masked by the processing of the tracer previous to its detection in breath. While the LCLM and SSM showed a rapid initial emptying phase (no lag phase), the HCLM has an initial slow emptying phase. The slower gastric emptying of the HCLM compared to the SSM was related to the presence of a lag phase in the gastric emptying of the HCLM.
  
  
  CONCLUSIONS
  The 13C-acetate breath test is very accurate to identify and study the lag phase if present of liquid meals.
authors.affiliation: Dpt. of Clinical Biochemistry, Clínica Universitaria de Navarra, Pamplona, Spain. agonzaleh@unav.es
authors.forename: A
authors.initials: A
authors.lastname: González
authors.forename: C
authors.initials: C
authors.lastname: Mugueta
authors.forename: D
authors.initials: D
authors.lastname: Parra
authors.forename: I
authors.initials: I
authors.lastname: Labayen
authors.forename: A
authors.initials: A
authors.lastname: Martinez
authors.forename: N
authors.initials: N
authors.lastname: Varo
authors.forename: I
authors.initials: I
authors.lastname: Monreal
authors.forename: M J
authors.initials: MJ
authors.lastname: Gil
mesh_terms: D000085:Acetates / Q000032:analysis; D001944:Breath Tests / Q000379:methods*; D002250:Carbon Radioisotopes / Q000032:analysis; D005502:Food; D005746:Gastric Emptying; D006801:Humans; D007553:Isotope Labeling; D010316:Particle Size; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D000085:Acetates; D002250:Carbon Radioisotopes