[Sanserif]

So...according to a new study by Harvard researchers in the online journal Human Reproduction, men who consume a modest amount of soy products have much lower sperm concentrations.

Is this because soy makes them girly-men? Or does this happen because soy increases semen volume, diluting the sperm concentration? Or do men with low sperm counts seek out soy products.

Haven't posted enough times here to include a URL, but there are about a hundred news stories on it today. Here's an excerpt from the Forbes story:

For the study, Chavarro and colleagues collected data on 99 men who attended a fertility clinic for evaluation. The men were asked about how much of 15 soy-based foods they ate in the past three months.

The foods men were asked about included tofu, tempeh, tofu or soy sausages, bacon, burgers, soy milk, cheese, yogurt, ice cream and other soy products like roasted nuts and energy bars.

Because different foods have different levels of isoflavones, half a serving of soy is equal to about one cup of soy milk or one serving of tofu or soy burgers every other day, Chavarro noted.

Chavarro's team found that men who ate the most soy had 41 million fewer sperm per milliliter of semen compared with men who did not eat soy foods. Normal sperm counts range between 80 million and 120 million per milliliter, according to a press release from the journal, a monthly publication of the European Society for Human Reproduction and Embryology.

In addition, the researchers found that the link between soy and sperm concentration was stronger among overweight and obese men. Overweight and obese men produce more estrogen than thinner men, and soy may increase those estrogen levels even further, they speculated.

Moreover, the link between soy and sperm concentration was strongest in men with higher sperm concentrations. Men who have normal or high sperm counts may be more susceptible to soy foods than men with low sperm counts, Chavarro said.

[MrBrightside]

There have been a lot of reports claiming it raises estrogen, and other that claim that soy has no impact on your hormones. I play it safe and don't eat the stuff.

[HPatel650]

hmm.. ive been drinking a glass a day for like a month so i hope im not damaged

[beebab]

This is a very convoluted subject. Some studies suggest that consuming a modest amount of soy protein has the same muscle-building capacities as consuming whey or other dairy derived proteins with zero impact on serum testosterone levels, whereas other studies will tell you the contrary. I don't know what to believe honestly, but I am a proponent of diversity in diet. I think that it's healthy to vary your protein sources and consume protein from eggs, meats, fish, whey and yes, soy. I think it's a negative thing to make soy protein the main protein source in your diet; however, if you consume a very generous amount of soy during the week alongside other protein sources, the result would only be beneficial to your body. Remember, soy also has an abundance of other health benefits besides being used for workout supplementation. And honestly, in my own opinion all this hype about soy supposedly reducing testosterone levels is just that --- a bunch of ridiculous hype, much like how pre/ PWO nutrition is ridiculously overhyped. Believe what you hear to some degree and never refute any piece of info as untrue, but never fully believe what you hear as complete fact.

[Dietfreak]

Spot on Beebab! Too often people get caught up in details that cannot be conclusively substantiated. They do more harm worrying about it (counter-regulatory hormones) than taking it would produce.

[suncloud]

so here's the question. with soy and its estrogen promoting values - that most studies say doesn't happen in HEALTHY men, who wants to do a log of only soy pre and post workout during PCT when their test is suppressed? someone take this and run with it, and put the rumors to their test..osterone...

[OV33]

I think that if you are a Vegetarian surviving off Soy then you may have to worry. As far as Soy protien in your diet I don't believe will effect you if you have other sources of protiens in your diet. I'm not knocking Vegetarians either and I know there is alot of other sources of protien besides meat. I just prefer meat in my diet. I figure somebody gave me incisors for a reason.