Genetically modified soya beans may cause allergy


Jeffrey Smith has been writing and campaigning on the danger of GM soya (among other topics) for some years – for more information see his website

He maintains that there are many ways in which genetic engineering may cause allergies and that the rapid growth in allergies, especially amongst children, may be caused by the genetic modification of our foods.

In the mid 1990s, in an attempt to add selenium to soya beans, a gene from the Brazil nut was engineered into the soya bean. Subsequent tests showed that people allergic to Brazil nuts also reacted to the GM beans. The bean was never marketed.


The GM variety of soya planted in 91% of US soya acres is Monsanto's Roundup Ready – engineered to survive otherwise deadly applications of their Roundup herbicide. The plants contain genes from bacteria which produce a protein that has never been part of the human food supply.

Before humans have allergic reactions to foods they need to be sensitized to those foods by coming into contact (eg eating) them.  Because the bacterial genes used in the RoundUp Ready have never been part of the food chain, there are no advance tests to show whether they may or may not prove allergenic in humans.

To get around this problem, the new proteins were compared with a database of proteins known to cause allergies. Guidelines from the WHO instructed that if the new GM protein contained amino acid sequences that had been shown to trigger immune responses in other proteins, the GM crop should not be sold or planted. Or not, at least, until additional testing had been done.

In fact, sections of the protein produced in GM soya proved to be identical to shrimp and dust mite allergens - but the soybean got marketed anyway. Frighteningly, the only published human feeding study on GM foods ever conducted verified that the gene inserted into GM soy transfers into the DNA of our gut bacteria and continues to function. This means that years after we stop eating GM soy, we may still have the potentially allergenic protein continuously produced within our intestines.

Collateral damage

The process of creating a GM crop produces massive collateral damage in the plant’s DNA. Native genes can be mutated, deleted, permanently turned on or off, and hundreds may change their levels of protein expression. This can increase existing allergen, or produce a new, unknown allergens. Both appear to have happened in GM soy.

Studies have shown that levels of one known soy allergen, trypsin inhibitor, were up to seven times higher in cooked GM soya compared to cooked non-GM soya. Another study discovered a unique, unexpected protein in GM soya, likely to trigger allergies.

In addition, of eight human subjects who had a skin-prick (allergy-type) reaction to GM soya, seven also reacted to non-GM soya but one did not, suggesting that the allergy had nothing to do with the soya bean but with its genetic modification.

Pesticide residues

Farmers use nearly double the amount of herbicide on GM soya as they do on non-GM soya; higher herbicide residues may cause allergic/intolerance reactions especially in people who are already chemically sensitive.

Warnings ignored

Documents made public from a lawsuit revealed that FDA scientists were uniformly concerned that GM foods might create hard-to-detect allergies, toxins, new diseases, and nutritional problems but their urgent requests for required long-term feeding studies fell on deaf ears.

The FDA (US Food and Drug Administration) does not require a single safety test before licensing GM soya. The person in charge of that FDA policy was Monsanto’s former attorney, who later became their vice president.


Buying products that are organic or labeled non-GMO are two ways to limit your family’s risk. Another is to avoid products containing any ingredients from the seven GM food crops: soy, corn, cottonseed, canola, Hawaiian papaya, and a little bit of zucchini (courgette) and crook neck squash. This means avoiding soya lecithin in chocolate, corn syrup in candies, and cottonseed or canola oil in snack foods.

To learn more about the health dangers of GMOs, and what you can do to help end the genetic engineering of our food supply, visit

First Published in 2010

If this article was of interest you will find many other articles on unlikely allergies and allergy connections here – and links to many relevant research studies here.

For more on the more 'mainstream' allergies check in to our 'allergy and intolerance home page' – and for ideas on alternative foods go here.

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