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United States Department of Agriculture

Agricultural Research Service

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updated 11/6/03


Allergic to Certain FoodsAnimated red question mark.

If you're allergic to certain foods, you may be familiar with some of these Animated eyeballsuncomfortable symptoms: watery eyes, itchy rashes, burp!--gas, or a throat that feels so tight it's hard to breathe.

Eggs, milk, peanuts, wheat, fish, shellfish, tree nuts and soybeans are the "Big Eight" foods that can contain allergens. These are substances that can cause you to have an allergic reaction. People who are allergic to these foods usually have to avoid eating them. But this can be difficult, since so many good things to eat contain parts of these foods as ingredients.

Photo graph of soy-based products, including printing ink. Soybeans--used in flours, baby formulas, cereals, "veggie burgers," and even pet food--are no exception. And it turns out that when someone is allergic to soy products, what they're usually reacting to is a protein called "P34" that's in the soybeans.

Animated soybean graphic. Now, a solution to the problem of P34 is being studied by scientistsat the Agricultural Research Service (ARS), the University of Arkansas (UA), and Pioneer Hi-Bred International, a seed company.

The scientists' idea: shut down a soybean gene that makes the bothersome protein.

Graphic of DNA molecule. Genes are part of a ladder-shaped molecule called DNA that's in all living organisms. DNA stands for deoxyribonucleic acid (dee-oxee-ry-bo-newCLAY-ic-acid). It is like an instructional manual that shows how something is made, how it should look, and how it should work. You might think of a gene as a page in that DNA manual.

So what's all this got to do withsoybean plants and allergies?

What the scientists did was fool the soybean plant into tearing out a page from its own DNA manual--the page for making the P34 protein. The plant didn't literally take it out, though. Here's what happened. In the laboratory, the scientists placed anextra copy of the gene into the plant's DNA. That caused certain changes that the soybean plant read as: Virus Attack!In response, the plant completely shut off its own P34 gene, plus the extra copy that the scientists snuck into its DNA.

The result: no P34 protein was made--at all!

Scientists call soybeans with the missing P34 protein "hypoallergenic"(HY-po-al-er-GEN-ick) since those beans are less likely to cause an allergy. At least, that's what the scientists hope!

Butterfly graphic.So far, the P34 protein hasn't shown up in tests designed to detect it. Also, plants of hypo-allergenic bean crops look just like those that have the protein. That's the report from Eliot Herman, with ARS in St. Louis, Missouri, and Rick Helm, with UA's Arkansas Children's Hospital, in Little Rock.

Photo of Eliot Herman, left, lab technician Gael Cockrell, middle, and Rick Helm, right.There, Helm is feeding the hypoallergenic beans to pigs to see how they'll react. Eventually, that research could lead to tests with people.

But, Helm warns, "You're never going to make a completely allergy-free soybean plantbecause you're not going to be able to eliminate all the proteins in it." Instead, the goal is to make a safer product for people who are sensitive to soy. That could also shorten the list of food products those people have had to avoid.

-- By Jan Suszkiw, Agricultural Research Service, Information Staff

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Last Modified: 8/12/2016
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