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For
some of us, soy has a downside
August 12, 2009
Suzanne Havala Hobbs
America
has discovered the joy of soy.
Not long ago, it would have required a trip to the health
food store for most of us to find soymilk or a veggie burger
patty. No more.
These and other soyfoods, including tofu, tempeh, and soy-based
substitutes for ground beef, bacon, hot dogs and cold cuts
are now entrenched on the shelves at most supermarkets.
Why?
Demand for these products has grown rapidly. In part, we’re
more sophisticated eaters today, with more of us exposed to
and interested in foods from other cultures such as in Eastern
Asia where soy is commonly used.
The biggest driver of demand for soy, though, is the health
benefit. Soy protein has been demonstrated by research to
lower blood cholesterol levels.
And soyfoods may be particularly beneficial when they replace
meat counterparts such as hot dogs, burgers and cold cuts
that contain animal proteins and artery-clogging saturated
fat and cholesterol.
For a small but notable percentage of us, though, there may
be a downside to our new-found love of soy. Soy, it turns
out, joins milk, eggs, peanuts, tree nuts, wheat and seafood
as one of a handful of the most common foods with allergens.
Food allergies affect 6 percent to 8 percent of young children
and nearly 4 percent of adults.
Where soy is concerned, allergies are commonly associated
with infants who react to soy-based infant formulas. The allergy
usually goes away by 3 to 5 years of age.
But as soy ingredients turn up in more foods, soy allergy
is also affecting more adults. Researchers haven’t confirmed
which components of soy cause the allergic reaction, but several
proteins found in soy have been shown to be allergenic.
Soy allergy may cause any of a number of symptoms, including
abdominal pain, diarrhea, nausea, or vomiting, wheezing, a
runny nose or difficulty breathing, or skin conditions such
as hives or eczema.
It’s possible to have a severe allergic reaction to
soy, but mild to moderate symptoms are more common. That’s
why some people – yours truly included – have
endured symptoms for years before realizing they had a soy
allergy.
If you suspect you may have a soy allergy, check in with your
doctor to determine whether testing may be helpful.
You can also test your hunch with an elimination diet. Cut
soy out of your diet for a period of a few weeks and see whether
you notice an improvement in allergy symptoms.
Like magic, my own symptoms disappeared in a few days when
I switched from soymilk to rice milk on my morning cereal
and cut out other soyfoods. They reappeared within hours after
a eating a Thai tofu and peanut sauce dish during a recent
vacation.
Obvious potential culprits include soybeans or edamame, soymilk,
tofu, tempeh, soy-based veggie burgers, hot dogs and similar
products. Other soy-containing foods include soy sauce, miso,
natto, soy flour and soy albumin, hydrolyzed soy protein,
textured vegetable protein (TVP) and tamari.
Allergic individuals may vary in the extent to which they
can include soy-containing foods in their diets without having
symptoms. Some people, for example, may be able to tolerate
soybean oil (which contains no protein) or soy sauce without
problems.
Read food labels to spot soy ingredients, and use trial and
error to determine which foods may be associated with symptoms.
Soy is used so extensively in processed foods these days that
it can be hard to avoid it. A good source for detailed information
about label reading and living with a soy allergy is the Food
Allergy Survival Guide by Melina, Stepaniak and Aronson (Healthy
Living Publications, 2004).
For most people, soy is a joy – a healthful, good-tasting
and versatile addition to your diet. However, if you’re
experiencing food allergy symptoms, don’t overlook soy
as your suspect.
Suzanne
Havala Hobbs is a licensed, registered dietitian and clinical
associate professor in the Department of Health Policy and
Management and the Department of Nutrition in the UNC Gillings
School of Global Public Health. Send questions and comments
to suzanne@onthetable.net.
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