You Aren't What You Eat

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Science  30 Jan 2004:
Vol. 303, Issue 5658, pp. 591-593
DOI: 10.1126/science.303.5658.591e

One of the concerns about genetically modified foods is the potential for transfer of foreign genetic material (for instance, antibiotic resistance genes) into either our own cells or those of organisms resident within our bodies, such as intestinal bacteria. Studies of gene transfer from plants to livestock have generally shown that most DNA is destroyed in the harsh conditions of the gut and hence little is found in animal feces.

Netherwood et al. have carried out a similar test in seven human volunteers who had undergone ileostomy, a procedure in which the last section of the small intestine is removed and the intestinal contents are diverted into a colostomy bag. After a breakfast of a soy burger and milk shake, the levels of the herbicide resistance transgene 5-enolpyruvylshikimate-3-phosphate synthase were measured, with only 3.7% of the initial amount consumed found in one individual's digesta and much less in the other six people. In a trial of humans with intact gastrointestinal tracts fed the same meal, none of the transgene was detected in their feces, suggesting that DNases produced by flora of the large intestine degrade whatever survives transit through the stomach and small intestine. — GJC

Nature Biotechnol. 10.1038/nbt934 (2004).

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