title: Metabolomic biomarkers for obesity in humans: a short review.
abstract: BACKGROUND
  The prevalence and incidence of obesity have become a major public health problem during the last decades, but the underlying biochemical and metabolic processes are not fully understood. Metabolomics, the science of small molecules of the metabolism, is helping to unravel these mechanisms via the identification of markers related to obesity. These biomarkers are used to prevent diseases in later life or for the early diagnosis of diseases. This review focuses on articles dealing with biomarkers for obesity.
  
  
  CONCLUSIONS
  Branched-chain amino acids (BCAA), nonesterified fatty acids, organic acids, acylcarnitines, and phospholipids were identified as potential biomarkers for obesity. This indicates a relation between elevated BCAA, and other amino acids, and the obese state. Furthermore, deregulation of β-oxidation is associated with the development of obesity. The results have several limitations, including the differing ages of the subjects in the studies, the fact that all of the studies had a case-control design and therefore no causal explanatory power, and that most looked for similar metabolites and reported almost equal results.
  
  
  CONCLUSIONS
  The strength of this review is that it gives a comprehensive overview of the current status of the knowledge on metabolomics biomarkers for obesity, but further research is needed because the methods used in the studies to date are very homogenous, e.g. most used a targeted approach and therefore analyzed almost the same group of metabolites. Moreover, prospective studies are lacking since all of the studies are either case-control or cross-sectional studies.
authors.affiliation: Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, Ludwig Maximilian University of Munich, Munich, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Rauschert
authors.forename: Olaf
authors.initials: O
authors.lastname: Uhl
authors.forename: Berthold
authors.initials: B
authors.lastname: Koletzko
authors.forename: Christian
authors.initials: C
authors.lastname: Hellmuth
mesh_terms: D000597:Amino Acids, Branched-Chain / Q000097:blood / Q000378:metabolism; D015415:Biomarkers / Q000097:blood / Q000378:metabolism / Q000652:urine; D002331:Carnitine / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism / Q000652:urine; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D006801:Humans; D055432:Metabolomics / Q000379:methods; D009765:Obesity / Q000097:blood / Q000378:metabolism* / Q000652:urine
chemical_list: D000597:Amino Acids, Branched-Chain; D015415:Biomarkers; C116917:acylcarnitine; D002331:Carnitine