title: Metabolic changes in serum metabolome in response to a meal.
abstract: OBJECTIVE
  The change in serum metabolic response from fasting state to postprandial state provides novel insights into the impact of a single meal on human metabolism. Therefore, this study explored changes in serum metabolite profile after a single meal.
  
  
  METHODS
  Nineteen healthy postmenopausal women with normal glucose tolerance participated in the study. They received a meal consisting of refined wheat bread (50 g carbohydrates, 9 g protein, 4.2 g fat and 2.7 g dietary fibre), 40 g cucumber and 300 mL noncaloric orange drink. Blood samples were collected at fasting and five postprandial time points. Metabolic profile was measured by nuclear magnetic resonance and targeted liquid chromatography-mass spectrometry. Changes over time were assessed with multivariate models and ANOVA, with baseline as control.
  
  
  RESULTS
  The metabolomic analyses demonstrated alterations in phospholipids, amino acids and their breakdown products, glycolytic products, acylcarnitines and ketone bodies after a single meal. More specifically, phosphatidylcholines, lysophosphatidylcholines and citrate displayed an overall declining pattern, while leucine, isoleucine, methionine and succinate increased initially but declined thereafter. A sharp decline in acylcarnitines and ketone bodies and increase in glycolytic products postprandially suggest a switch in the body's energy source from β-oxidation to glycolysis. Moreover, individuals with relatively high postprandial insulin responses generated a higher postprandial leucine responses compared to participants with lower insulin responses.
  
  
  CONCLUSIONS
  The study demonstrated complex changes from catabolic to anabolic metabolism after a meal and indicated that the extent of postprandial responses is different between individuals with high and low insulin response.
authors.affiliation: Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 7015, 75007, Uppsala, Sweden.
authors.forename: Aahana
authors.initials: A
authors.lastname: Shrestha
authors.affiliation: Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 7015, 75007, Uppsala, Sweden. elisabeth.mullner@slu.se.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Müllner
authors.affiliation: Department of Clinical Nutrition, Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, 70211, Kuopio, Finland.|VTT Technical Research Centre of Finland, Tietotie 2, P.O. Box 1000, 02044, Espoo, Finland.
authors.forename: Kaisa
authors.initials: K
authors.lastname: Poutanen
authors.affiliation: Department of Clinical Nutrition, Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, 70211, Kuopio, Finland.
authors.forename: Hannu
authors.initials: H
authors.lastname: Mykkänen
authors.affiliation: Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 7015, 75007, Uppsala, Sweden.
authors.forename: Ali A
authors.initials: AA
authors.lastname: Moazzami
mesh_terms: D000368:Aged; D000596:Amino Acids / Q000097:blood; D001786:Blood Glucose / Q000032:analysis; D001939:Bread; D002331:Carnitine / Q000031:analogs & derivatives / Q000097:blood; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004043:Dietary Fiber / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D004734:Energy Metabolism; D005215:Fasting; D005260:Female; D006019:Glycolysis; D006801:Humans; D007328:Insulin / Q000097:blood; D007657:Ketone Bodies / Q000097:blood; D007930:Leucine / Q000097:blood; D062407:Meals; D055442:Metabolome / Q000502:physiology*; D008875:Middle Aged; D010743:Phospholipids / Q000097:blood; D017698:Postmenopause; D019518:Postprandial Period; D014908:Triticum
chemical_list: D000596:Amino Acids; D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004043:Dietary Fiber; D004044:Dietary Proteins; D007328:Insulin; D007657:Ketone Bodies; D010743:Phospholipids; C116917:acylcarnitine; D007930:Leucine; D002331:Carnitine
keywords: Acylcarnitine; Amino acid; Glycolytic products; Insulin; Metabolomics; Phosphatidylcholine; Postprandial changes