GM crop DNA found in human gut bugs

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GM crop DNA found in human gut bugs

Jan 15, 2004 09:30 PST

 

 

New Scientist

12:10 18 July 02

 

GM crop DNA found in human gut bugs

Andy Coghlan

 

http://online.sfsu.edu/%7Erone/GEessays/GMhumangutbugs.html

 

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.

 

http://online.sfsu.edu/%7Erone/GEessays/GMhumangutbugs.html

 

12:10 18 July 02

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