Supplements Question: Soy protein and test level

(If this can be moved to the supplements forum that would be great!)

I have one big question that’s been on the back of my mind for a while now, would consuming soy protein isolate (from protein bars, cereals, etc) lower the amount of testosterone in your body?

I read in a study that for men, consumption of soy products can lower testosterone levels to below normal. Now, I personally love my high testosterone levels and don’t want to screw them up by eating the wrong things. Could anyone tell me if soy protein isolate would lower testosterone levels? As it is you find soy in everything these days, and I’d say I consume about 50-75g of soy protein per day.

Here are some sources that are FOR soy protein lowering testosterone levels:
http://www.t-na tion.com/findAr … icle=302poison2
http://www.moth ering.com/artic … /soy_story.html
http://www.gyma … on.com/soy.html

Sources that are AGAINST soy protein lowering test. Levels:
Yahoo | Mail, Weather, Search, Politics, News, Finance, Sports & Videos

http://www.powe ringmuscles.com … stosterone.html

Neutrals:
Too much Soy lowers testosterone?
Soybean - Wikipedia

Edit: I just checked the ingredients label on my whey protein, even that stuff has soy products! Is there anything out there without soy in it!

As you’ve seen, there are plenty of facts out there to support either side, you just gotta make up your own mind I guess.

Personally I don’t like soy enough to risk it, except for soy sauce. :-P

If your looking for a protein source and are lactose intolerant there are other sources such as egg protein, hemp protein, and there is even whey protein with the lactose removed.

Hah! - Try looking at what Licorice does to testosterone levels.

Really? Do you have any sources?

Good thing I’m not a licorice man either.

Read up on Dr Eugene Shippen - he’s the man, and he says Soy is good for Test levels :)

First, just looking at the links you attached, I can tell there is little chance for any real scientific discussion of the soy/testosterone question. Especially yahoo answers….that’s where I go when I want a 12 year olds to answer my important questions.

Here are a couple of links to real scientific studies on the question. But also keep in mind that results of these studies often are determined by who is funding the research. For example, if Hood milk is funding a study that shows drinking soymilk lowers testosterone levels you have to really question the results.

Soy protein isolates of varying isoflavone content exert minor effects on serum reproductive hormones in healthy young men

Serum prostate-specific antigen but not testosterone levels decrease in a randomized soy intervention among men

Soy milk intake in relation to serum sex hormone levels in British men

Dietary soy-phytoestrogens decrease testosterone levels and prostate weight without altering LH, prostate 5alpha-reductase or testicular steroidogenic acute regulatory peptide levels in adult male Sprague-Dawley rats

These are just a few but there is definitely conflicting data. I myself eat alot of soy products but I think I have too much testosterone anyway, so if it does lower levels, it’s probably a good thing. Peace.

Thanks for the links suziesun12, I know the yahoo answers one isn’t very legitimate but I included it in there anyway, sometimes people can have remarkable insight on them but 90% of the time it’s a 12 year old or someone who has no idea what they’re talking about answering the question.

I try to avoid soy when I can which is hard to do since it’s in everything

There is a ton of conflicting data on this question.

Soy, like corn in the USA, is a big cash crop. That’s why it goes in everything. Pro-soy corporations sponsor a whole bunch of research to encourage it’s consumption - much of it isn’t legit. Soy does have some health benefits in small amounts, but ever since the OMG ASIAN PEOPLE LIVE FOREVER BECAUSE THEY EAT SOY health food craze started in the late 90’s, it has been seen as “safe” in the popular culture. This is a fallacy, because in Japan, aside from Buddhist monks who eat tofu specifically to “repress urges”, it isn’t the main protein source - Fish is! Soy/Tofu is a side dish, often enough! After reading a ton of information on both sides, I find that soy, at least for men, is probably detrimental. Having some tofu now and then isn’t going to cause a problem, but watch your “everyday” foods and certainly don’t use it as a protein substitute! As Dino said, it’s in just about everything these days. For women, the case may be different,

I suggest shopping at a health food store and looking for soy-free items. If you’re worried about protein, I encourage the use of Hemp protein instead. Not only is it very complete in terms of amino acids and the like, it doesn’t have any of the estrogen effects of soy, in my research.