QCan you give me some peer reviewed references that discuss the health effects of the various proteins expressed in Bt corn. In particular quoting Syngenta's website, Syngenta's Attribute II is supposedly active against Beet Armyworm (Spodoptera exigua),

Can you give me some peer reviewed references that discuss the health effects of the various proteins expressed in Bt corn. In particular quoting Syngenta's website, Syngenta's Attribute II is supposedly active against Beet Armyworm (Spodoptera exigua), Black Cutworm(Agrotis ipsilon), Common Stalk Borer(Papaipema nebris), Corn Earworm(Helicoverpa zea), Dingy Cutworm(Feltia jaculifera), European Corn Borer(Ostrinia nubilalis), Fall Armyworm(Spodoptera frugiperda), Southern Cornstalk Borer(Diatraea crambidoides), Southwestern Corn Borer(Diatraea grandiosella), Sugarcane Borer(Diatraea saccharalis), and Western Bean Cutworm(Striacosta albi). Has there been any long term studies of Attribute II's health effects?

AExpert Answer

Attribute II sweet corn expresses the vegetative insecticidal protein Vip3A and the crystalline protein Cry1Ab, both of which are derived from the naturally occurring soil microorganism Bacillus thuringiensis (Bt).  Bt spores and proteins have been used worldwide for many decades in both organic and conventional farming as a direct application pesticide for vegetable and fruit crops, and thus there is a long history of safe use and exposure.  Both of these proteins are highly selective in terms of their toxicity because they bind to specific receptors that are found in the midgut of certain insect species, but not found in other insects or vertebrate animals.  These two proteins are therefore only toxic to the larvae (caterpillars) of certain Lepidopteran insects that are key agricultural pests, but are harmless to other insects, fish, reptiles, birds and mammals, including humans.  Here is a recent article that discusses the safety of Bt proteins that you may find useful:


Hammond B.G. and Koch M.S. (2012). A Review of the Food Safety of Bt Crops, In: Bacillus thuringiensis Biotechnology, E. Sansinenea (ed.). Springer: New York. Pp. 305-325.


To answer your second question, long term studies have not been conducted of Attribute II, nor are they necessary.  Attribute II expresses transgenic proteins which have been demonstrated to be: 1) rapidly digestible by humans as other dietary proteins, 2) denatured and inactivated by heat (as from cooking), and 3) completely nontoxic in laboratory mice and rats exposed to levels many hundreds of times higher than humans could possibly be exposed to.  As these proteins are easily digested and nontoxic, and as Attribute II sweet corn has been demonstrated to otherwise be substantially equivalent to conventional varieties of sweet corn, there is simply no need for further testing as there is no biological plausibility for chronic toxicity potential.  Here is a recent article that supports this position that long term studies are not necessary to evaluate the safety of genetically modified crops:


Snell C., Bernheim A., Bergé J.-B., Kuntz M., Pascal G., Paris A., Ricroch A.E. (2012). Assessment of the health impact of GM plants in long-term and multigenerational animal feeding trials: a literature review. Food and Chemical Toxicology 50:1134-1148.


Lastly, expression of these proteins by Attribute II and other corn varieties is beneficial in terms of food safety.  Minimized insect feeding damage is directly correlated with reduced infection of the corn ear by the ubiquitous fungi that produce mycotoxins, many of which potent liver and kidney toxins and carcinogens.

Posted on January 31, 2018
Thank you for your question. There are various aspects of your question. I assume your question refers to the use of Agrobacterium rhizogenes by scientists to intentionally transfer genes from the bacterium to plants. Infection and DNA transfer from this bacterium occurs in nature all the time to cause disease. Such transformed plants are not classified as GMOs since transfer occurred naturally. If this is done by scientists then it would be classified as a GMO. Rules and... Read More
Posted on March 1, 2018
I’m a Monsanto scientist who has more than 20 years of experience with genetic modification of plants. I will try to answer your question, even though I don’t ever do experiments on animals, certainly not on humans, of course! Can humans be genetically modified…but a much bigger question is should humans be genetically modified? There are two ways to think about genetic modification of humans (or any animal). One way is modification of somatic cells, and the other is the... Read More
Posted on May 10, 2017
The simple answer is that 20+ years of composition assessments of GMO crops have demonstrated that crop composition is not appreciably affected by the GM process (1). In addition, data collected through that time have indicated that general factors such as the growth environment can contribute to notable variation in component levels (2). Plant agglutinins (or lectins) and amylase inhibitors are examples of anti-nutritional compounds that may be present in crops. The relevance of such a... Read More