Regarding GM foods (GM formula?) and the gut, the latest Dr. Mercola
newsletter
http://mercola.com/2002/aug/3/gm_food.htm
quotes the July 18, 2002 New Scientist
Judy Ritchie
http://www.newscientist.com/news/news.jsp?id=ns99992565
GM crop DNA found in human gut bugs
12:10 18 July 02
NewScientist.com news service
For the first time, it has been proved that bacteria in the human gut
can take up DNA from genetically modified food.
However, the UK's Food Standards Agency, which commissioned the
research, says that the overall findings are reassuring rather than
alarming because the amount taken up was barely detectable and only
occurred in special circumstances.
Nonetheless, opponents of GM foods say the results vindicate their
warnings that this might happen, and that the risk of gut bacteria
scavenging antibiotic resistance genes from GM food is no longer
theoretical.
"This is a first," says Adrian Bebb of the Friends of the Earth. "We've
said time and time again there's a risk of this happening. Now, they've
looked just once and they've found it."
Burger and shake
Harry Gilbert and colleagues at the University of Newcastle upon Tyne
made the discovery, after feeding volunteers with a burger and a milk
shake containing GM soya.
To see how the GM food was dealt with by different parts of the
digestive system, he gave the food to 12 healthy volunteers and to seven
volunteers who had previously had their colons surgically removed.
When he examined stools from the healthy volunteers, he found no traces
whatever of DNA from the GM food. It had all been digested. Nor did he
find any evidence that gut bacteria had taken up the DNA.
But when he examined waste products collected from the seven ileostomy
bags, he found that up to 3.7 per cent of the GM DNA survived.
Crucially, in three of the seven, he found that bacteria had taken up GM
DNA from the soya. But "despite exhaustive attempts", he could not
isolate the precise bacteria which had taken up the GM DNA. He concludes
that the DNA must have been taken up only by tiny proportions of gut
bacteria.
Destructive enzyme
To account for the differences between the "ileostomists" and volunteers
with intact digestive systems, Gilbert's team speculate that DNA might
survive the small bowel but gets completely destroyed in the large
bowel. They say in a draft manuscript that people with ileostomies might
produce less of the enzyme that degrades DNA.
As supporting evidence, they found that unmodified soya DNA survived in
the small bowel as plentifully as the GM DNA. "It shows that the GM DNA
acts in the body the same way as DNA from regular food," says a
spokeswoman from the FSA.
In a separate experiment on colonies of intestinal cells, Gilbert's team
showed that raw loops of GM DNA called plasmids can be taken up
directly, but only by one gut cell in 3000.
Bacteria containing the same plasmids proved totally incapable of
transferring their genetic cargo into the gut cells. "These data support
the view that GM soya does not represent a significant risk to human
health through gene transfer," says the Gilbert team.
Andy Coghlan
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