Is soy a safe way to energize your body?

What's one to make of it?

Soy, which comes in many forms and is derived from soybeans, has long
had the reputation of being a near perfect health food – offering loads
of protein with little calories and fat. For years, the government and
nutritionists have praised soy, pointing to the health of Asian
populations where soy is a diet staple.

When soy started hitting the mainstream, it was reportedly supposed to
lower cholesterol, alleviate menopause symptoms, even help prevent
cancer.

But soy has its detractors, too. Some nutritionists complain not only
are soy's benefits overstated, but there are also plenty of drawbacks
as well. They say a diet laden with soy can impact fertility, affect
the thyroid and even cause heart problems.

Critics also point out that the type of soy Americans eat is
different from that of Asia, which is mostly fermented forms such as
tempeh and miso. Much of the soy consumed in the United States is both
highly processed and made from genetically modified soy beans. The
upshot: Even though Asian populations don't seem to suffer any ill
effects from soy, like reduced fertility, that doesn't necessarily
translate to U.S. consumers.

So what's a lover of soy – which is in everything from edamame
to soy milk to Boca burgers – to make of it all? Is it time to put soy
on the shelf with the seemingly ever-expanding list of shouldn't-eat
foods?

Not necessarily.

As in all things, the truth lies between the two extremes, said Joan
Rupp, a professor of nutrition at San Diego State University.

While there have been some animal studies that have found such side
effects as reduced fertility and thyroid issues, those problems have
not been established in any long-term human studies. As far as the
current research goes, Rupp said, it supports the belief that a diet
with moderate soy consumption is both safe and healthy because
substituting animal protein for plant protein is always a good way to
cut saturated fat from your diet. Still, eating soy is not the health
panacea that some might envision.

“There's a place for soy, but you don't want to go overboard
with it,” she said. “Everyone is always looking for that magic pill in
terms of their health. From what it looks like now, soy isn't going to
be it.”

Still not sure what to make of soy? Here's a rundown of some of its potential benefits and drawbacks.

Does soy lower cholesterol?

Sure, but not by much. Studies have found that a soy-rich
diet can reduce LDL (bad) cholesterol between 3 percent and 6 percent.
Those with extremely high cholesterol may benefit the most. Just
remember that overloading on soy, consuming beyond the recommended
limit of 25 grams a day, won't bring your cholesterol down any further.

Does soy reduce fertility?

Not so far as we know, say most nutritionists, physicians
and researchers. They point to Asian populations where there are no
such fertility problems. Still, a recent Harvard study found that men
who eat approximately half a serving of soy did experience a reduced
sperm count. But many studies have found no conclusive evidence that
soy causes fertility problems in humans although there have been some
issues in animal studies. Soy does have phytoestrogen, a plant form of
the female hormone estrogen, but the American Academy of Pediatrics
says it is not worried about the hormonal effects on children.

Is soy-based baby formula dangerous?

The American Academy of Pediatrics says no. Still, there's
no real reason to use soy formula instead of formula derived from cow's
milk, said Dr. Frank Greer, who recently studied the soy formula issue
for the organization.

Does soy help with menopause symptoms?

Maybe, a little bit. According to the National Institutes
of Health, some studies suggest that soy supplements may reduce hot
flashes in women after menopause. However, the results have been
inconsistent.

Does soy help prevent breast cancer?

It might if soy consumption begins at a very young age but
the science is inconclusive. That goes for prostate cancer, too. But
nutritionists and physicians say women who have breast cancer should be
careful of eating soy because of the estrogen component. As the NIH
puts it, women at risk of developing hormone-sensitive conditions such
as breast cancer or ovarian cancer should consult with their doctor
about their soy intake.

Does soy help prevent heart disease?

Since it lowers a person's cholesterol, it can. Still,
soy's overall heart benefits are in question. The American Heart
Association has scaled back its earlier recommendation of a soy-rich
diet because of the limited benefit in preventing heart disease. One
study of male mice genetically programmed to develop heart disease
found that those with a soy-rich diet were more prone to heart failure
than those on a dairy diet. Typical caveat: It's still unclear if that
study has any relevance for humans.

source:http://www.signonsandiego.com/news/health/20080513-9999-1c13soym.html