We recently received an inquiry regarding a report from the University of Sherbrooke Hospital Centre in Quebec. The report claimed to have detected the presence of the Bt protein Cry1Ab in the blood of humans. The report, which was highlighted in an article from The Organic Report is available here*.
The individual who sent us the report wanted to know what this means for human health and how concerned he and other consumers should be, based on the findings.
We enlisted the help of two experts - their feedback is below.
Dr. Wayne Parrott, University of Georgia - Athens
The study out of the University of Sherbrooke Hospital Centre in Quebec reported finding Bt proteins in the blood of several women. This protein is found in some types of GM corn, and finding it in human blood raised several questions for me.
- First, the find was surprising because the protein is normally destroyed by cooking, and people simply do not eat enough raw corn to account for the amount of protein the researchers claimed was in the blood**.
- Secondly, lab tests had found that if it is not destroyed by cooking, the protein was readily destroyed by stomach acid.
- Third, the researchers from the University of Sherbrooke used a test kit that works exactly like a home pregnancy kit. Just like a home pregnancy kit is designed to work on urine, the researchers used a kit that was designed to work on powdered plant tissue. However, rather than powdered plant tissue, they used human blood. Others have tried to use the same test kit with blood before, and never could get it to work. The kit is simply not designed to work with human blood.
The prevailing view in the scientific community is that the researchers simply got wrong results from using the wrong type of test. This is just a case of medical researchers not being familiar with the tools of plant research, rather than a new discovery that one should be concerned about.
Dr. Bruce Chassy, University of Illinois - Urbana
The results are difficult to reconcile with the reality that more than 99% of Bt-corn is not sold in markets and consumed whole by consumers. Tortillas and tortilla chips are an exception, but these are cooked products (cooking destroys Bt). It is therefore unclear by what route or in what foods women could have been exposed to Bt-corn.
Animal feeding studies have shown that Bt is not absorbed from corn fed to animals but is digested and absorbed as peptides and amino acids; no Bt can be detected in meat, milk and other products isolated from Bt-corn fed animals. The results reported in this study are not consistent with the scientific literature.
Finally, the levels of Bt claimed in the study are far higher than would be expected even if Bt from Bt corn were transported intact into the serum and tissues; Bt-corn contains very low levels of Bt and consumption of Bt-corn by women in Quebec is most probably negligible.
Seeing the results of a study that used inappropriate methods (applying human blood to a plant tissue testing kit) causes concern regarding the motives of the authors and/or editors who conducted and reported on the study.
*If you are unable to access the link, copy and paste the following URL into your browser: http://ipaperus.ipaperus.com/OTA/TheOrganicReport/TheOrganicReportSummer2011/?Page=18.
**This post has been updated to reflect the fact that while a very small percentage of humans consume raw corn, people do not eat enough raw corn to account for the amount of protein the researchers claimed was in the blood.