title: Serum S-adenosylmethionine, but not methionine, increases in response to overfeeding in humans.
abstract: BACKGROUND
  Plasma concentration of the methyl donor S-adenosylmethionine (SAM) is linearly associated with body mass index (BMI) and fat mass. As SAM is a high-energy compound and a sensor of cellular nutrient status, we hypothesized that SAM would increase with overfeeding.
  
  
  METHODS
  Forty normal to overweight men and women were overfed by 1250 kcal per day for 28 days.
  
  
  RESULTS
  Serum SAM increased from 106 to 130 nmol/l (P=0.006). In stratified analysis, only those with weight gain above the median (high-weight gainers; average weight gain 3.9±0.3 kg) had increased SAM (+42%, P=0.001), whereas low-weight gainers (weight gain 1.5±0.2 kg) did not (Pinteraction=0.018). Overfeeding did not alter serum concentrations of the SAM precursor, methionine or the products, S-adenosyl-homocysteine and homocysteine. The SAM/SAH (S-adenosylhomocysteine) ratio was unchanged in the total population, but increased in high-weight gainers (+52%, P=0.006, Pinteraction =0.005). Change in SAM correlated positively with change in weight (r=0.33, P=0.041) and fat mass (r=0.44, P=0.009), but not with change in protein intake or plasma methionine, glucose, insulin or low-density lipoprotein (LDL)-cholesterol.
  
  
  CONCLUSIONS
  Overfeeding raised serum SAM in proportion to the fat mass gained. The increase in SAM may help stabilize methionine levels, and denotes a responsiveness of SAM to nutrient state in humans. The role of SAM in human energy metabolism deserves further attention.
authors.affiliation: Department of Physiology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt.
authors.forename: A K
authors.initials: AK
authors.lastname: Elshorbagy
authors.affiliation: Department of Pharmacology, University of Oxford, Oxford, UK.
authors.forename: F
authors.initials: F
authors.lastname: Jernerén
authors.affiliation: Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.|Division of Diabetes and Metabolism, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Samocha-Bonet
authors.affiliation: Department of Pharmacology, University of Oxford, Oxford, UK.|Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
authors.forename: H
authors.initials: H
authors.lastname: Refsum
authors.affiliation: Division of Diabetes and Metabolism, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia.|Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: L K
authors.initials: LK
authors.lastname: Heilbronn
mesh_terms: D000273:Adipose Tissue; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D008078:Cholesterol, LDL / Q000097:blood; D003430:Cross-Sectional Studies; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008715:Methionine / Q000097:blood*; D044343:Overnutrition / Q000097:blood*; D012436:S-Adenosylmethionine / Q000097:blood*; D015430:Weight Gain
chemical_list: D001786:Blood Glucose; D008078:Cholesterol, LDL; D004041:Dietary Fats; D004044:Dietary Proteins; D007328:Insulin; D012436:S-Adenosylmethionine; D008715:Methionine