3rd quarter 2006

Reduced mycotoxin burden in Bt maize results in health benefits

This hypothesis is advocated in an article by L. Kershen in the American "Food and Drug Law Journal". The idea was prompted by the increased incidence of pregnancies with embryonic neural tube defects in the Rio Grande valley in the early 90’s. This was remarkable because the women had been taking the amount of folic acid recommended by the US Public Health Service since 1992, and the incidence of embryonic neural tube defects had been clearly reduced by this measure in other regions. Why did folic acid food supplementation remain ineffective in the Rio Grande valley? A strikingly high amount of unprocessed maize is consumed in the Rio Grande valley region. This maize is often contaminated with the mycotoxin fumonisin which is produced by the Fusarium fungus. A study conducted in 2004 showed that fumonisin inhibits the uptake of folic acid from food at the molecular level and so impedes the positive action of folic acid on neural tube defects.

The larvae of the corn stem borer open the portals to the Fusarium fungus, i.e., the greater the stem borer infestation, the greater the Fusarium infestation, and thus the higher the fumonisin burden in the food/feed. Bt maize inhibits stem borer infestation and therefore contains far lower levels of mycotoxin than more conventional maize. According to a study by the Spanish IRTA (Institute of Agro-Food Research and Technology), the mycotoxin burden in Bt maize was about 83% lower than in conventional maize. This is confirmed by other studies in Argentina, France, Italy and the USA. The US FDA and the European Commission have already set down guidelines for the maximum fumonisin content of food and feeds. In his paper Kershen discusses various possibilities for further regulatory and legal consequences: from education campaigns and fumonisin monitoring up to warning notices on non-Bt products.

Summary

Mycotoxins are a well-known problem in food and feeds. They incur costs in healthcare and reduce harvests in agriculture. The cultivation of Bt maize can be seen as one of many possibilities for reducing the mycotoxin burden.