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Is Genetically Modified Food An Environmental Hazard?

Scientists can insert genes into food plants in order to make them grow better or be resistant to certain diseases or environmental conditions.  Some people are afraid of such genetically modified plants, because these new genes might get into animals or humans or the ecosystem and cause unexpected bad effects.

Many European countries ban the importing of such genetically modified plants. This causes a problem for U.S. farmers, because many of them rely on genetically modified plants and many export markets are closed to them.

Is That A Reasonable Fear?

Many scientists don't believe it could be a problem. When either animals or humans eat genetically modified food, the DNA in that food is digested - especially by microbes that live in the gut that have enzymes that breakdown DNA. So the question should be: does any DNA pass through intact in the feces?

So What Is the Evidence?

Studies so far suggest there is no problem:

1.  One experiment has been done on seven human volunteers who had surgery in which the last section of the small intestine had to be removed, with the contents diverted into a collection bag. When they ate food that had a gene in it for herbicide resistance, all subjects showed a maximum of 3.7% or less of the gene had survived. This suggests that stomach and small intestine digestive juices destroyed most of the gene.

2.  When the same food was eaten by volunteers who had complete digestive tracts, NO trace of the gene appeared in the feces. This suggests that the microbes in the large intestine complete the destruction of any remnants of the gene that survive the small intestine.

HOWEVER: it is possible for genetic change to occur in insects that feed on genetically engineered plants - this may have happened in monarch butterflies.

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