title: [Use of tests based on the analysis of expired air in nutritional studies].
abstract: Tests based on the analysis of the gaseous components of expired air have been developed to study intestinal absorption and intermediary metabolism of various nutrients. This paper reviews the breath-analysis tests based on the measurement of CH4, H2, and isotopically-labelled CO2 for studying the intestinal absorption of carbohydrates, fats, and bile salts, and intrahepatic metabolism. New technology employing mass spectrometry allows the use of the stable isotope, carbon-13, instead of the radioactive isotope, carbon-14, for CO2 breath tests. The nutritional application of the breath-analysis tests is discussed, and the advantages of the non-radioactive, non-invasive procedures, especially for use in children and pregnant women in whom standard investigational methods represent a discomfort or a radioactive hazard, are emphasized.
mesh_terms: D001647:Bile Acids and Salts / Q000378:metabolism; D001944:Breath Tests; D002245:Carbon Dioxide / Q000378:metabolism; D002247:Carbon Isotopes; D002248:Carbon Monoxide / Q000378:metabolism; D002849:Chromatography, Gas; D004032:Diet; D004040:Dietary Carbohydrates / Q000378:metabolism; D004041:Dietary Fats / Q000378:metabolism; D005740:Gases / Q000378:metabolism; D006000:Glycocholic Acid / Q000378:metabolism; D006801:Humans; D006859:Hydrogen / Q000378:metabolism; D007408:Intestinal Absorption; D007422:Intestines / Q000502:physiology*; D007785:Lactose / Q000008:administration & dosage; D008697:Methane / Q000378:metabolism; D014994:Xylose / Q000378:metabolism
chemical_list: D001647:Bile Acids and Salts; D002247:Carbon Isotopes; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D005740:Gases; D002245:Carbon Dioxide; D002248:Carbon Monoxide; D006859:Hydrogen; D014994:Xylose; D006000:Glycocholic Acid; D007785:Lactose; D008697:Methane
vernacular_title: El uso de pruebas basadas en el análisis del aire espirado, en estudios nutricionales.