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). Design and interventions: This was a randomised crossover study. Subjects consumed 50 mg trigonelline, 5 g of instant coffee (≈ 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. Setting: Christchurch Clinical Studies Trust, Christchurch, New Zealand. Subjects: 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.) 4h (0.7±0.2 μmol/l, P=0.006), 5h (0.7±0.2μmol/l, P=0.013) and 7h (0.7±0.2μmol/l, P=0.024) following coffee consumption. Urinary glycine betaine excretion was increased by coffee but not by trigonelline. Conclusion: Ingestion of instant coffee acutely elevated plasma Hcy; however, trigonelline is not responsible for this rise. © 2004 Nature Publishing Group. All rights reserved.