Magic Bean or Tragic Bean? A Closer
Look at Soy
By Denis Faye
From the Million Dollar Body Club - Join Today and Workout to
in: Soy prevents cancer. Soy lowers "bad" cholesterol. Soy prevents
osteoporosis. Hooray! Bring on the tofu!
Wait! More breaking
news: Soy suppresses thyroid function. Soy hinders testosterone. Soy
causes cancer. Oh no! Looks like it's back to beef burgers for me.
Welcome to the food wars. On one
side, big business tells us what to eat. On the other side, watchdog groups
tell us we're being poisoned. From the wings, the media screams about the
battle at the top of its lungs. In the middle stands our poor diet, constantly
scrutinized. Sooner or later, everything we eat is either branded the next
superfood fad or the devil incarnate. Every now and then, a food comes along
that gets to be both. Ladies and gentlemen, I give you soy.
Then and now
The soybean, which
comes from East Asia, made its way to the United States in 1804. Through the
1930s, its primary use was as livestock feed. But in the last seventy years,
things have changed. America is now the world's foremost soybean producer and,
from an economical standpoint, soybeans are one of the world's most important
In much the same way one of
America's other big crops, corn, has found its way into just about every
packaged food in the country in the form of high-fructose corn syrup, the food
industry has come up with all kinds of inventive uses for soy. It's used to
make paints, glues, bug sprays, and food. And we're not just talking tofu here.
From soy milk to cereals to protein bars to meat substitutes, the stuff is
The good news and the bad
Because the soybean
is such an economic powerhouse, it's often in the spotlight. The FDA states
that soy is a "complete protein," meaning that it's just as good as meat, eggs,
and dairy in fulfilling your amino acid needs. Is this true or has the soybean
lobby just leaned on the FDA to say that? And what of the miracle food claims.
Are they true?
These, of course, are then
followed by the crusaders attempting to bring down the soy monolith. How can
their claims be true, too? After all, scientific studies are infallible,
Not so much. It's an incredibly
difficult topic to get the straight dope on and an incredibly easy topic to
manipulate. So, trying as best as possible not to buy into any hype, let's take
a look at soy.
The Asian argument
The first argument
out of the pro-soy lobby's mouth is, "Look at Asia! They've been eating soy for
centuries and they're super-healthy!"
Generalizations aside, this is
true, except Asian cultures don't go all Coneheads on the stuff, consuming vast
quantities. A 1990 study from Cornell University concluded that the average
Chinese diet consisted of between 0 and 58 grams of soy a day with the average
being 13 gramsabout half an ounce.
In much the same way that the
French can pull off eating creamy cheeses and chocolate and remain thin, the
secret to eating anything, healthy or decadent, is moderation.
Above and beyond any
miracle cures, it's important to remember soy's primary function in most
people's diets: to provide a lean, meat-free protein. How well does it do this?
According to the Food and Agriculture Organization and World Health
Organization (FAO/WHO), it does just fine.
In 1989, the FAO/WHO developed
the Protein Digestibility Corrected Amino Acid Score, a method of measuring
protein values in human nutrition. Eggs, milk, and soy all score a 1.0, the
best possible. Beef scores .92 and peanuts score .52.
So, from purely a macronutrient
point of view, soy looks to be good stuff. Yet, for some reason, we seem
determined to ruin it. Sure, the protein is still there in soy sausage or fake
bacon or faux chicken, but so are the sodium and huge laundry list of chemicals
it took to morph it. A tolerable soy burger has 230 mg of sodium10
percent of the recommended daily allowance. A bad one, like the Boca Burger All
American Classic, has 500 mg. For reference, an average beef patty has about 42
mg of sodium.
So if you're looking for
protein, stick to soybeans, tofu, and soy milk and leave the weird meat
Soybeans are also one of the
very few nonanimal sources, alongside flax and canola, of omega-3 fatty acids,
which help the body on a variety of levels. So especially for vegetarians,
that's worth considering.
Miracles and scares
Most of soy's
miracle claims and scares are based on rather flimsy studies. For example, a
study in the Archives of Internal Medicine showed that among 24,403
postmenopausal Chinese women, those who ate soy-heavy diets had a 37 percent
lower risk of broken bones. That's good news until you look at the findings in
a cultural context, as the watchdog group The Center for Science in the Public
Interest points out in their newsletter, Nutrition Action. American
women consume considerably more dairy than Chinese women, which has a huge
influence on bone strength. Furthermore, they're already more prone to hip
fractures, so the study is moot.
As for studies indicating soy
can lower LDL "bad" cholesterol levels, a review in 2005 sponsored by the
federal government's Agency for Healthcare Research Quality showed that to see
a measly 3 percent reduction, one had to eat a pound of tofu a day.
As for the scares, the
much-ballyhooed 1985 USDA Trypsin Inhibitor Study showed that rats on a
primarily soy diet had an increased risk of pancreatic cancer. It's all really
scary until you learn that a rat's pancreas has a sensitivity to dietary
protease inhibitors, a substance in soy that inhibits digestion of proteins.
Humans have no such sensitivity. In other words, rat pancreases and human
pancreases are different enough to bring the study into question.
It just goes back and forth like
Isoflavone of the month
One thing everyone
agrees on is that soy is loaded with isoflavones, an organic compound that is
thought by some experts to be a tool in treating cancer. There have been
studies that suggest the isoflavones in soy may help prevent prostate cancer,
hot flashes, osteoporosis, and brain aging. So why not consume as many
isoflavones as you can? Well, there's a downside.
Isoflavones are a type of
phytoestrogen, a chemical produced in plants that acts like estrogen when
introduced into animal bodies. With this in mind, a 2001 Canadian study and a
2006 California study suggest that women with a high risk of breast cancer be
mindful about the amount of soy they consume. There are also several studies
that suggest it's a bad idea to give infants soy formula due to the
isoflavonesbut before anyone freaks out, there are also several studies
that say soy formula isn't a problem at all. You just can't win.
How much is too much?
Before just giving up on soy
because you just can't be bothered with the data, consider this alternative:
moderation. The Center for Science in the Public Interest
suggests limiting soy so that you ingest about 50 to 70 milligrams of
isoflavones a day. That's one or two cups of soy milk or 6 to 9 ounces of tofu.
That should be enough to tap the benefits without overdoing it.
But also keep in mind that
because soy is such a huge industry in the United States, manufacturers can get
it cheap, so they find ways of shoving it into everything. Whenever you're
buying some kind of processed food, read the ingredients. You're probably
eating more soy than you know.
Even if there weren't concerns
about soy, this would still be a good number to shoot for. Regardless of
whether or not a food is the miracle nutrient of the moment, excess never
works. If you focus on one thing too much, you're neglecting a myriad of other
important nutrientsthe balance of which will make for great health.