Soy and Testosterone Levels?

I've recently heard several people say that eating soy will
screw up your hormone levels by increasing estrogen. Can
anyone tell me if this is true, and if so what is the actual
biochemistry of this effect?

I've been doing a little research, and the only thing that I
came up with is that soy inhibits the aromatise enzyme
(which converts testosterone into estrogen), so that you have
higher levels of testosterone, not lower.

Thanks.

Soy has phytoestrogens. So it could, supposedly, mess up your biochemistry if you eat nothing but soy.

Don't eat only soy. It's as simple as that. Short of it, you'll be just fine.

-doug-

I'd stick with whey. It's hard to argue soy vs whey and go with soy. It's cheap, tastes decent, what else do you need?

I always use whey protein powder--not soy.

I was more concerned about things like soy beans
(edamame), tofu, and various soy products like garden
burgers.

Thanks all.

There are a lot of Asians that eat soy with every meal and are doing just fine...

or so we think...

"There are a lot of Asians that eat soy with every meal and
are doing just fine... "

Yes, during my poking around on this topic I read some
research about the amount of soy in the average Japanese
person's diet.

First off, interestingly, fermented soy products, like miso and
tempeh, don't have the same kind of estrogen-like
compounds.

Secondly, the percentage of calories that comes from soy on
a daily basis was very small, somewhere on the order of just
a few percent, IIRC.

And finally, there was a study of Japanese people who
moved to Hawaii that showed that after they moved they
were more succeptible to various illnesses. The research
couldn't conclude what exactly may have caused that, but
there was speculation that it may have been somehow
related to a change away from the traditional Japanese diet.

Anecdotally, when I travelled in China, even when I was
living in a Buddhist monastery, I was surprised at how little
tofu was eaten. From what I could gather, soy foods were not
common at all. The diet was mostly rice, steamed or fried
breads, vegetables, and beans.

Every airline that has ever crashed has served peanuts.
Thus, peanuts cause airline crashes.

Just because an epidemiological study relates factor X to syndrome Y, doesn't mean that X is causal of Y.

Soy has had many animal studies DIRECTLY demonstrating its ill-effects on hormone levels.

Various t-mag.com articles make a good point that soy protein is found in HIGH concentration in MANY different food items in the US. This is probably the problem, not to mention environmental estrogens.

I was recently in Japan. I ate a lot of japanese food.
Not many food items had soy protein in them. I would say the US probably consumes more soy that asia.

"First off, interestingly, fermented soy products, like miso and tempeh, don't have the same kind of estrogen-like compounds."


Ok, gotcha

Soy protein tastes like crap and is an inferior source of protein as far as its biological value. That in and of itself should dissuade people from opting to purchase soy protein over Whey, Egg, Casein, etc...

As I said, I was thinking more of soy foods (like garden
burgers and tofu), and I was really interested in knowing the
actual biochemistry involved in how soy alters hormone levels.

But thanks for sharing about the crappy taste.

most of the articles I have read about soy-protein-only diets tend to geared towards strength training and bodybuilding. so in a way the articles may be targeted to those groups of people. i don't soy is a quick way to have gains in the different areas, where as meat is a quicker way than soy. but what I found hilarious was the history of soy products starting from the bean which was supposedly fertilizer until there was an excess surplus of it was pawned off as food to people and to animals/livestock. can ya believe that?

"the history of soy products starting from the bean which was
supposedly fertilizer until there was an excess surplus of it
was pawned off as food to people and to animals/livestock.
can ya believe that? "

Wow! I had never heard that before.

never heard of that before this yr, so I did call a friend who teaches Asian History at UH and he confirmed it. But from the article I read about that historical fact, the rest of the author's stuff seemed weird.

Any links to articles where the increase in estrogen effects of soy are discussed?

Any links to articles where the increase in estrogen effects of soy are discussed?

Yep, there are (at least) two good articles at t-mag.com on that very subject. I'll post the links if I can find them.edit to add links:http://www.t-mag.com/html/body_143soy.htmlhttp://t-mag.com/html/body_87prote.html

Phytoestrogens don't lower your testosterone any more than 'natural' anaobolics raise it. Nobody believes the latter, yet everyone is eager to jump on the former.

Nothing wrong with soy.

When you just eat animal protein your body will be acidic soon.

I have soy shakes 2-3 times a day and I feel really good. It is good protein and better than eating 5 pound chicken and 10 eggs a day.

http://westonaprice.org/soy/index.html

-lots of convincing evidence there...

All things in moderation.