title: Effects of coffee consumption on subclinical inflammation and other risk factors for type 2 diabetes: a clinical trial.
abstract: BACKGROUND
  Coffee consumption is associated with a decreased risk of type 2 diabetes. Suggested mechanisms underlying the association have included attenuation of subclinical inflammation and a reduction in oxidative stress.
  
  
  OBJECTIVE
  The aim was to investigate the effects of daily coffee consumption on biomarkers of coffee intake, subclinical inflammation, oxidative stress, glucose, and lipid metabolism.
  
  
  METHODS
  Habitual coffee drinkers (n = 47) refrained for 1 mo from coffee drinking; in the second month they consumed 4 cups of filtered coffee/d and in the third month 8 cups of filtered coffee/d (150 mL/cup). Blood samples were analyzed by gas chromatography-mass spectrometry, bead-based multiplex technology, enzyme-linked immunosorbent assay, or immunonephelometry.
  
  
  RESULTS
  Coffee consumption led to an increase in coffee-derived compounds, mainly serum caffeine, chlorogenic acid, and caffeic acid metabolites. Significant changes were also observed for serum concentrations of interleukin-18, 8-isoprostane, and adiponectin (medians: -8%, -16%, and 6%, respectively; consumption of 8 compared with 0 cups coffee/d). Serum concentrations of total cholesterol, HDL cholesterol, and apolipoprotein A-I increased significantly by 12%, 7%, and 4%, respectively, whereas the ratios of LDL to HDL cholesterol and of apolipoprotein B to apolipoprotein A-I decreased significantly by 8% and 9%, respectively (8 compared with 0 cups coffee/d). No changes were seen for markers of glucose metabolism in an oral-glucose-tolerance test.
  
  
  CONCLUSIONS
  Coffee consumption appears to have beneficial effects on subclinical inflammation and HDL cholesterol, whereas no changes in glucose metabolism were found in our study. Furthermore, many coffee-derived methylxanthines and caffeic acid metabolites appear to be useful as biomarkers of coffee intake.
authors.affiliation: Institute of Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich, Heine University Düsseldorf, Düsseldorf, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Kempf
authors.forename: Christian
authors.initials: C
authors.lastname: Herder
authors.forename: Iris
authors.initials: I
authors.lastname: Erlund
authors.forename: Hubert
authors.initials: H
authors.lastname: Kolb
authors.forename: Stephan
authors.initials: S
authors.lastname: Martin
authors.forename: Maren
authors.initials: M
authors.lastname: Carstensen
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Koenig
authors.forename: Jouko
authors.initials: J
authors.lastname: Sundvall
authors.forename: Siamak
authors.initials: S
authors.lastname: Bidel
authors.forename: Suvi
authors.initials: S
authors.lastname: Kuha
authors.forename: Jaakko
authors.initials: J
authors.lastname: Tuomilehto
mesh_terms: D052242:Adiponectin / Q000097:blood; D000328:Adult; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001053:Apolipoproteins / Q000097:blood; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D002109:Caffeic Acids / Q000097:blood / Q000378:metabolism; D002110:Caffeine / Q000097:blood; D002726:Chlorogenic Acid / Q000097:blood; D002784:Cholesterol / Q000097:blood; D003069:Coffee / Q000737:chemistry*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood; D005260:Female; D006801:Humans; D007249:Inflammation / Q000188:drug therapy*; D020382:Interleukin-18 / Q000097:blood; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D028321:Plant Preparations / Q000494:pharmacology / Q000627:therapeutic use*; D012307:Risk Factors; D016037:Single-Blind Method
chemical_list: D052242:Adiponectin; D000893:Anti-Inflammatory Agents; D001053:Apolipoproteins; D015415:Biomarkers; D001786:Blood Glucose; D002109:Caffeic Acids; D003069:Coffee; D020382:Interleukin-18; D008055:Lipids; D028321:Plant Preparations; C075750:8-epi-prostaglandin F2alpha; D002726:Chlorogenic Acid; D002110:Caffeine; D002784:Cholesterol; D015237:Dinoprost; C040048:caffeic acid