title: Heavy coffee consumption and plasma homocysteine: a randomized controlled trial in healthy volunteers.
abstract: BACKGROUND
  An elevated plasma concentration of total homocysteine is considered to be a strong risk factor for cardiovascular disease. Heavy coffee drinking has been related to high homocysteine concentrations in epidemiologic studies and in one experiment in which healthy subjects drank unfiltered, boiled coffee.
  
  
  OBJECTIVE
  Our goal was to determine whether daily consumption of paper-filtered coffee raises plasma concentrations of total homocysteine in healthy subjects.
  
  
  METHODS
  Twenty-six volunteers (18-53 y of age) consumed 1 L/d of paper-filtered coffee brewed with 70 g regular ground beans or no coffee for 4 wk each in a randomized, crossover design.
  
  
  RESULTS
  The mean (+/-SD) plasma concentration of total homocysteine in fasting blood was 8.1 +/- 1.8 micromol/L after abstention from coffee and 9.6 +/- 2.9 micromol/L after 3-4 wk of coffee drinking, a difference of 1.5 micromol/L (95% CI: 0.9, 2.1 micromol/L) or 18% (P: < 0.001). Coffee increased homocysteine concentrations in 24 of 26 individuals. Circulating concentrations of vitamin B-6, vitamin B-12, and folate were unaffected.
  
  
  CONCLUSIONS
  Drinking large quantities of paper-filtered coffee raises fasting plasma concentrations of total homocysteine in healthy individuals.
authors.affiliation: Wageningen Centre for Food Sciences, Nutrition and Health Programme, Wageningen, Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Urgert
authors.forename: T
authors.initials: T
authors.lastname: van Vliet
authors.forename: P L
authors.initials: PL
authors.lastname: Zock
authors.forename: M B
authors.initials: MB
authors.lastname: Katan
mesh_terms: D000328:Adult; D002110:Caffeine / Q000008:administration & dosage; D003069:Coffee / Q000009:adverse effects*; D005215:Fasting; D005260:Female; D005374:Filtration; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D003069:Coffee; D006710:Homocysteine; D002110:Caffeine