The Washington Post
05-31-07
There's no harm in enjoying edamame
By Bonnie S. Benwick
The Washington Post
Q. I've heard that eating edamame inhibits the body's ability to digest protein and
might be unhealthy in other ways. Some quick Internet research hasn't turned up
much credible reporting, but I'm concerned because I love edamame. I eat the
frozen kind all the time and love to serve it as a party snack.
Do you have any info about health effects of edamame, or can you point me in
the right direction?
A. Not to worry. According to Lester Wilson, a food science and human
nutrition specialist at Iowa State University, raw soybeans contain an enzyme
called trypsin as well as trypsin inhibitors, which are natural compounds that can
affect the body's ability to break down proteins. (For non-science types, Wilson
likens this to a key that is jammed in a door lock, preventing the door from being
opened. We generate such enzymes in our bodies, too.)
Most likely, the edamame you're snacking on is not raw. It has been blanched,
steamed, roasted or otherwise heat-treated, the professor says, which inactivates
or denatures the inhibitor that might otherwise bind with the enzyme and keep
you from getting all of the protein benefit of eating soy.
Depending on the temperature and heating time involved, a tiny amount of
trypsin inhibitor might remain, but not enough to cause harm (it might even be
good for you because it is thought to be an anti-cancer compound), unless
perhaps your immune system is severely compromised.
That said, Wilson recalls that long ago, protein quality testing done on rats did
result in data that showed adverse effects of soy on the rats' development. But in
that instance, Wilson says, the rat model and human model were apples and
oranges, so to speak. We have more enzymes to digest proteins in our bodies
than rats do.