title: Trigonelline is not responsible for the acute increase in plasma homocysteine following ingestion of instant coffee.
abstract: OBJECTIVE
  To determine whether trigonelline contributes to the effect of coffee on homocysteine (Hcy).
  
  
  METHODS
  This was a randomised crossover study. Subjects consumed 50 mg trigonelline, 5 g of instant coffee (approximately 50 mg trigonelline) or water, consumed as a single dose in 100 ml, with 1 week between each treatment. Blood samples were drawn fasting and hourly for 8 h. Urine samples were collected pretreatment and every 2 h for 8 h.
  
  
  METHODS
  Christchurch Clinical Studies Trust, Christchurch, New Zealand.
  
  
  METHODS
  Eight healthy male subjects.
  
  
  RESULTS
  Instant coffee raised plasma Hcy concentrations compared with water (P=0.019) and trigonelline (P=0.037). Plasma Hcy concentrations were not different between water and trigonelline treatments (P=0.789). The change in plasma Hcy concentration was higher (mean+/-s.e.) 4 h (0.7+/-0.2 micromol/l, P=0.006), 5 h (0.7+/-0.2 micromol/l, P=0.013) and 7 h (0.7+/-0.2 micromol/l, P=0.024) following coffee consumption. Urinary glycine betaine excretion was increased by coffee but not by trigonelline.
  
  
  CONCLUSIONS
  Ingestion of instant coffee acutely elevated plasma Hcy; however, trigonelline is not responsible for this rise.
  
  
  BACKGROUND
  Supported by the Health Research Council, the Canterbury Medical Foundation, the Foundation of Research, Science and Technology.
authors.affiliation: Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand. sandy.slow@cdhb.govt.nz
authors.forename: S
authors.initials: S
authors.lastname: Slow
authors.forename: W E
authors.initials: WE
authors.lastname: Miller
authors.forename: D O
authors.initials: DO
authors.lastname: McGregor
authors.forename: M B
authors.initials: MB
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Lever
authors.forename: P M
authors.initials: PM
authors.lastname: George
authors.forename: S T
authors.initials: ST
authors.lastname: Chambers
mesh_terms: D000328:Adult; D000470:Alkaloids / Q000494:pharmacology*; D019540:Area Under Curve; D003069:Coffee; D018592:Cross-Over Studies; D005215:Fasting; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D010919:Placebos
chemical_list: D000470:Alkaloids; D003069:Coffee; D010919:Placebos; D006710:Homocysteine; C009560:trigonelline