In an abstract I read, it suggests that soy CAUSES an increased rate of breast tumor growth and inhibits an anti-tumor antagonist called tamoxifen:

http://www.ncbi.nlm.nih.gov/pubmed/11573864

Unfortunately I'm not able to read the full article, but it comes to that conclusion despite stating that at "high concentrations" (whatever that means) it has an opposite effect. From the abstract it also doesn't say whether the animals were male or female (i.e. already had elevated levels of estrogen).

Perhaps the general rule holds true that the more estrogen receptors activated, the higher risk of breast cancer-- at low concentrations the phytoestrogens can somehow fill in the gaps of other estrogen receptors while at higher concentrations (if in females) breast cancer rates are reduced since the weaker phytoestrogens compete with the much stronger natural E2s. Just my best guess.

I read from another random site:
http://www.drweil.com/drw/u/QAA401156/How-Safe-is-Soy.html

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Breast cancer: Theoretically, the phytoestrogens in soy can attach to estrogen receptors and block the effect of estrogen, the hormone most types of breast cancer cells need in order to multiply. If so, consuming soy foods could reduce the risk of breast cancer, but study results have been conflicting: some show that soy consumption lowers the risk of breast cancer while others have found no such evidence; some studies have even suggested that concentrated supplements of soy proteins may stimulate the growth of breast cancer cells. Results of a big study from Shanghai published in 2009 found that women participants whose intake of soy protein was highest when they were teenagers or young adults had a risk of pre-menopausal breast cancer that was 60 percent lower than participants whose soy protein intake during those young years was lowest. As far as other types of cancer are concerned, no good evidence demonstrates that substances in soy foods are protective against
endometrial, ovarian, colorectal, prostate and other cancers.
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Weaker estrogens replacing stronger estrogens can explain why female Asian populations that consume lots of soy products have low rates of breast cancer. What I would like to know is if anyone equivalently studied the male Asian population for breast cancer. From my gut-feeling, I think it will be hard to imagine that a bio male with as many estrogen receptors activated as a bio woman will not have an elevated risk of breast cancer compared to their regular low E male selves.

Overall, I think eating soy (at least non-GMO) moderately will have more benefits than harm, looking at all the vitamins it has. This link from cancer.org also provides the bottom line.

http://www.cancer.org/cancer/news/expertvoices/post/2012/08/02/the-bottom-line-on-soy-and-breast-cancer-risk.aspx

Does anyone have any thoughts?

My thought is that if the studies are inconclusive or contradictory the effect is inconsequential, so why worry about it?

Wasn't there a recent survey of worldwide studies of the cancer risk reducing benefits of eating fruits and vegetables that concluded there is no meaningful correlation contrary what was generally believed?

Now studies that show if you drink a glass of anti-freeze you are likely to die are worth heeding.

Clara

Overall, I think eating soy (at least non-GMO) moderately will have more benefits than harm,

Good luck finding it. Something like 95% of the soya crop in America is GMO.

The "health benefits" of soy are nothing but propaganda from the industry. The average American today consumes far more of it than the average Asian, because it's in everything. Pick up any box or can or bottle in the grocery store and read the label -- 99% of the time there will be soy something-or-other in it.

Soy is finally starting to get a bad rap. There's evidence that it is feminizing males (which is a bad thing for most of the population), and causing precocious puberty in girls. It's bad fuckin' news, and I avoid it like the plague.

Maybe one need not avoid it entirely... maybe a little is okay... but look through your pantry and refrigerator. Most Americans consume waaaaay too much of it.

I actually just came back from buying some tofu and soy milk from Trade Joe's. Of course it lists it all as organic, no preservatives, etc. but probably means it's still GMO?

Of course it lists it all as organic, no preservatives, etc. but probably means it's still GMO?

Well, legally, no. Something must be GMO-free (or almost entirely so) to earn a USDA Organic certification.

But because I know a bit about farming... and how many millions of tons of the stuff are processed from harvest, through elevators and trucks and trains, to factories where they manufacture the "food" products... there's simply no way to guarantee that's what you're actually getting.

Say the factory in question gets batches of organic soy from 100 different farms. Have they all been tested? Can you test a whole crop?

It's really become quite impossible to keep out all the GMO even with the strictest controls, outside of an individual farm-to-consumer direct sale. In other words, I know what I'm getting when I buy food from my friends' farms directly. That changes as soon as one middleman enters the picture. With your Trader Joe's product, it's been through a dozen.

Will it kill you? Probably not. If estrogenic properties of soy were the only concern, I'd be looking for some myself. We just don't know yet, though, what the long-term health consequences of consuming genetically modified foods will be, because they have been pushed into the marketplace without a single long-term study.

For me, I'm perfectly happy to eat things that humans have eaten for millenia. I don't have one ancestor who ever ate tofu... but plenty ate wheat, beef, dairy, root vegetables, fruits, etc.

Finally, I do support GMO labeling. It should be my choice to consume that technology. But since we do not have mandatory labeling, I just avoid products with soy, corn, and various vegetable oils. I can have a rich and varied diet without them.

You can get Non-GMO soy protein from Amazon:

Jarrow Formulas Iso-Rich Soy non-GMO
http://www.amazon.com/gp/product/B0013OQG64/ref=oh_details_o09_s00_i00?ie=UTF8&psc=1

In my research for my BNE program I have stumbled over dozen and dozens of studies about Soybean Isoflavones and possible cancer risk.

MissC is right, I also read a U.S. Food and Drug Administration report and it says "GE soybeans accounted for 93 percent of soybeans planted" in 2012.

U.S. Food and Drug Administration

Google Scholar search: soy isoflavones and cancer

Too many unknowns for my comfort.

Denita

Thanks for the find Denita, time to move to Asia! No, I love America. I think like many things I just consume in moderation (except if going on an NBE program).

In my research for my BNE program I have stumbled over dozen and dozens of studies about Soybean Isoflavones and possible cancer risk.

MissC is right, I also read a U.S. Food and Drug Administration report and it says "GE soybeans accounted for 93 percent of soybeans planted" in 2012.

U.S. Food and Drug Administration

Google Scholar search: soy isoflavones and cancer

Too many unknowns for my comfort.

Denita

Thanks for the find Denita, time to move to Asia! No, I love America. I think like many things I just consume in moderation (except if going on an NBE program).

In my research for my BNE program I have stumbled over dozen and dozens of studies about Soybean Isoflavones and possible cancer risk.

MissC is right, I also read a U.S. Food and Drug Administration report and it says "GE soybeans accounted for 93 percent of soybeans planted" in 2012.

U.S. Food and Drug Administration

Google Scholar search: soy isoflavones and cancer

Too many unknowns for my comfort.

Denita

While I believe that the risks of GM foodstuffs are often overrated, I have a different concern with the morality and safety of GM soybeans. This is that what I understand to be the most widely used or possibly the only modification is not intended for the purpose of improving the product, but for improving sales of Roundup herbicide. The modified soybean plants are undamaged by Roundup, which means that 'no-till' cultivation can be used, whereas the non GM soybeans will not have been treated with Roundup.