The kinetics of urinary fumonisin B1 excretion in humans consuming maize-based diets

Scope Fumonisins (FB) are mycotoxins found in maize. The purpose of this study was to (i) determine the relationship between FB1, FB2, and FB3 intake and urinary excretion in humans, (ii) validate a method to isolate urinary FB on C18-SPE cartridges for international shipment, and (iii) test the method using samples from Guatemala. Methods and results Volunteers (n = 10) consumed 206 grams/day of tortillas and biscuits prepared from masa flour and a product containing maize flour. Volunteers estimated their daily urine output and samples were analyzed for FB1, FB2, and FB3 and hydrolyzed FB1. Only FB1 was detected in urine suggesting lower absorption of FB2 and FB3. Excretion was highly variable peaking soon after consumption began and decreasing rapidly after consumption stopped. Within 5 days after consumption ended, FB1 was not detected in urine. In a study with eight volunteers, the average total urinary FB1 was 0.5% of the intake. FB1 was detected in 61% (107/177) of the samples collected in Guatemala. Conclusion The results support the use of urinary FB1 to assess ongoing exposure in popula-tion-based studies. However, relating the FB1 concentration in urine to dietary intake of FB by individual subjects will be complicated due to interindividual variability and the rapidity of clearance.