Dr. Andy

Reflections on medicine and biology among other things

Friday, April 29, 2005

Biotech food- danger or not?

I just finished an interesting article in the Annals of Allergy, Asthma and Immunology (not available except to subscribers) about the risks (or lack thereof) of genetically engineered crops.

One of the authors works for Monsanto, so keep that in mind.

Genetically modified crops are those where specific changes to the DNA are made using recombinant DNA technology, rather than the old-fashioned method of breeding plants and selecting for desired characteristics. The article points out that making the specific changes you want results in much less DNA shuffling, than breeding where large piecess of chromosome are shuffled

The article notes there are 3 ways biotech crops could be harmful

1. Addition of known allergenic proteins to existing crops. This would be bad and there was a transgenic soybean in development which expressed a Brazil nut protein. Luckily, the potential danger was detected and development halted.

2. Increasing expression of allergenic proteins. This could potentially increase severity of reaction in already allergic patients. It turns out that for foods like wheat and soy there are a lot of people who make IgE antibodies to antigens and may even have minor reactions to ingestion of large amounts but can take small amounts without problem. If all of a sudden, there was a lot more of the protein they are allergic to in the wheat, that could be bad. Studies so far have been reassuring.

3. Creation of new allergens. The idea is changing the proteins in a plant could create new allergies. The authors think this is unlikely and point out that several kinds of testing are done on bioengineered crops to make sure they are safe:
all genes introduced into food crops undergo a series of tests designed to determine if the biotech protein exhibits properties of known food allergens. All biotech proteins are assessed as to their source (allergenic or nonallergenic), any amino acid sequence similarity to known allergens, and their stability to digestion with proteases from the GI tract
I didn't know that did all that testing.

Finally the authors point out the potential exists to create HYPOallergenic foods by modifying particularly allergic proteins.

As background, if you are allergic to a food you don't react to every protein, but to one or more specific ones. Different people allergic to a food react to a similar but not identical subset of proteins. In other words, only a few proteins cause allergies.

The proteins that cause allergy share certain characterisitics like being resistant to digestion in the stomach.

I have long felt that bioengineered foods were likely to be safe, probably somewhat safer than crops derived from breeding and I am even more reassured about that safety after reading this article, primarily because of the testing the new crops undergo

2 Comments:

At 9:54 AM, Blogger jon said...

Looking at allergy asthma info online today while my son coughs I came across this post. Does anyone know a good allergy asthma site to help?

Thanks

 
At 4:18 PM, Anonymous Anonymous said...

Cool blog you have going here, I will check in often! I have a similar site about cub food. It pretty much covers cub food related stuff.

 

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