|
ARS ...
solving agricultural problems with science.
...
bridging the gap between science, agriculture and you.
updated 11/6/03
Allergic to Certain Foods
If
you're allergic to certain foods, you may be familiar with some of these uncomfortable 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.
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.
Now, a
solution to the problem of P34 is being studied by scientists at 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.
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
with soybean 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 an
extra 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!
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.
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
plant because 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
Top/ Back to

Related story:
ARS Scientists May Bring Relief to Peanut Allergy
Sufferers |