Trigonelline is not responsible for the acute increase in plasma homocysteine following ingestion of instant coffee.
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.
Slow
S
S
Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand. sandy.slow@cdhb.govt.nz
Miller
W E
WE
McGregor
D O
DO
Lee
M B
MB
Lever
M
M
George
P M
PM
Chambers
S T
ST
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
D000470:Alkaloids; D003069:Coffee; D010919:Placebos; D006710:Homocysteine; C009560:trigonelline