Submitted to: Toxicological Sciences
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2009
Publication Date: 3/1/2009
Citation: Riley, R.T. 2009. The kinetics of urinary fumonisin excretion in humans consuming maize-based foods. Toxicological Sciences. 114(S1):308-309. Interpretive Summary: Abstract - no summary required.
Technical Abstract: Fumonisins (FB) are mycotoxins found in maize worldwide. In Central America, South America and Mexico, maize-based foods are often a major part of the diet and FB intake can also be high. A study in Mexico found a significant correlation between urinary FB1 and maize tortilla consumption. The purpose of this study was to determine the relationship between FB intake and excretion in humans consuming maize-based foods in amounts that approximated maize consumption in urban Guatemala. The protocol was approved by the University of Georgia Institutional Review Board. Maize-based foods were purchased from local stores and analyzed for FB. All maize-based foods tested were positive for FB1 ranging from 18 ppb to 8 ppm. Commercial Masa flour and products containing predominantly maize flour often contained 1 to 3 ppm of FB1. Maize tortillas and maize-biscuits were prepared from these two products and 200 grams (six tortillas and five biscuits) were consumed by a single volunteer for three days. Urine samples were collected at each urination and total urine volume was recorded. This was also done for three days before and for five days after consuming the tortillas and biscuits. Seven additional volunteers consumed tortillas and biscuits but only collected a single urine sample every 24 h over 11 days of the study and provided estimates of total urine output each day. The urine was analyzed for FB1, FB2, FB3 and hydrolyzed FB1, FB2 and FB3. In all of the urine samples analyzed only FB1 was detected. Excretion in urine peaked at or soon after day 3 of consuming and 24 h later the level in urine was 25% of the maximum level and within five days after consumption ended FB1 was no longer detectable in the urine. The total amount of FB1 excreted in the urine was less than 0.1% of the total intake. The results indicate that the use of urinary FB1 as a marker to assess ongoing exposure in a population based study is possible but relating urinary levels to levels of exposure could be difficult due to individual variability and the rapidity of clearance.