Soy?

You know, I was also told to stay away from soy, but simply took that to mean don't drink soy milk or eat soybeans (edimame), or season with soy sauce, you know, the obvious sources of soy.

 I never thought to look at all the ingredients in the things I buy!

Hi, I too went through this debate quite some time ago and did searches in PubMed. PubMed is the U.S. National library of Medicine and carries research articles from all over the world.  My final interpretation is that it is not simple and that is why there is so many yeas and nays about it.

What I understand is that if you've been raised on soy like tofu you are likely protected and probably can continue to use it.  But not to use it for protection later in life.  Apparently the fermented soy products have the thumbs up for bc patients but the rest may or may not cause tumour growth.  It apparently is both an estrogen agonist and antagonist.

It is very hard to avoid and perhaps we should be contacting manufacturers about the use of soy in their products. They use soy oil in everything.  Probably because it is cheap.

I think soy gained it's popularity due to great marketing skills.  It contains an enzyme that inhibits protein digestion, it's goitrogenic (can create hypothyroidism) and I have just heard it can play a part in creating osteoporosis.

I'm sure there are people who will disagree, but that's what I've found through researching the topic. 

jan

This is a controversial one.  Miso, tofu and tempeh are all used extentsively throughout the Far East and they seem to have a much lower rate of breast cancer.  The idea is that phyto-estrogents are weaker, milder form of estrogens and by binding with cancer receptors they stop more harmful estrogens from doing the same (much in the same way that drugs like Tamoxifen do).  I find Jane Plant's argument in a book 'Your life in your hands' very convincing.  She had five breast cancer recurrences until she replaced dairy with soya products.  Another book I read says that soya milk and yogurt contain an ingredient which is not good for thyroid gland but that above mentioned fermented soya products are beneficial.

Nancy D - I have bought a bread making mashine and I make my own bread from organic flour.  It does a really good job and you can even time it.  You can also add things like seeds and nuts.

Best wishes Nena

I also avoid taking supplements with soy lecithin, or even when it states "vegetable oil" or any kind of 'vegetable' product, because they ALL are made from soy.  I know, it sounds like it couldn't be very much, but I figure if I can avoid getting soy in my diet through my supplements, that will help. 

I do eat chinese food occasionally, even though it has soy sauce in it.  I only have it maybe a couple of times per month, so I figure it is ok. 

I did just buy Quaker instant oatmeal, cinnamon swirl flavor.  They re-formulated it, and the packet reads "CONTAINS SOY".  Was I ever mad when I read this!!   I won't be eating it.

I know that there was a thread here about soy awhile back, and the feeling was that it can be ok, but to limit your intake.  I'll have to search for that thread.  It must have gone dormant due to non use.

Harley

This is the first time I hear about having to start consuming soy early in order to develop the tolerance to it although I have heard that soy protein is an allergen.  Perhaps the two are connected.

Thank you Wallycat for pointing me in the direction of Diana Dyer on cancerrd.com.  She states that in Japan women have much lower incidence of breast cancer and apparently the ones who develop it live (on average) longer than their western counterparts.  Of course there could be many and varied reasons for this but I was thinking that if soy was promoting breast cancer surely the longer one is exposed to it the risk would be greater.  Diana Dyer herself have been consuming 1 - 3 servings of traditional soy foods  since 1995 without a recurrence of her advanced and aggressive cancer during this time.  In any case I have replaced use of dairy products with soya products and will keep you posted.

Until they figure this out once and for all, I will try to avoid any variation of soy as much as possible, ditto flax and dairy. Although a little bit of something is probably okay. I will stick to my Rice Drink instead of milk or that soy stuff. I actually liked the vanilla flavored stuff on my cereal. And the only cheese I will eat, infrequently is the imported stuff. They have stricter guidelines on how they treat their animals.

This is only a mouse study (implanted human bc in mice), but it illustrates something that I think is important regarding soy in combination with other foods. BTW, soy has isoflavones--at least one isoflavone is an ER+ bc stimulator and the other seems to be neutral or non-stimulating. From my reading, eating whole soy is safest and this was mentioned above. Soy milk is not representative of whole soy when it comes to isoflavones.  Soy milk is absolutely loaded with them. If you're avoiding milk, try rice milk. Soy protein isolate was used in the study below--this too is high in isoflavones over the whole soy in tofu.

The abstract below appears to make the case that soy food can act as an estrogen in helping us maintain strong bones. Because it can also stimulate ER+ bc, taking it with flaxseed may be the combination that is most beneficial and safest:

Pubmed article on soy plus flax
 

 Mol Nutr Food Res. 2007 Jul;51(7):845-56.

Can the combination of flaxseed and its lignans with soy and its isoflavones reduce the growth stimulatory effect of soy and its isoflavones on established breast cancer?
Power KA, Thompson LU.

Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada.

Consumption of phytoestrogen (PE)-rich foods (i. e., soy and flaxseed (FS)) is increasing because of their suggested health benefits. However, recent studies raise concern over the safety of soy and its isoflavones, particularly genistein (GEN), for postmenopausal breast cancer (BC), due to their potential stimulatory effects on human breast tissue and on the growth of existing tumors in rodents. FS, rich in PE lignans, which is metabolized to the mammalian lignans enterolactone (ENL) and enterodiol (END), has consistently been shown to have tumor inhibitory effects in a human clinical trial as well as rodent BC models. Using the preclinical athymic mouse postmenopausal BC model, combining FS with soy protein or GEN with END and ENL, was found to negate the tumor stimulatory effects of soy protein or GEN alone. The mechanism may be related to the modulation of estrogen receptor and MAPK signaling pathways. If these studies can be confirmed in clinical trials, then consumption of combined soy and FS, or their PEs, may reduce the tumor growth stimulatory effect of soy or GEN. This may indicate that if soy is consumed with lignan-rich foods, it may continue to induce its other beneficial health effects, without inducing adverse effect on postmenopausal BC.

 and a follow on article by the same authors:

soy plus flax

 J Toxicol Environ Health A. 2007 Nov;70(22):1888-96.

Flaxseed and soy protein isolate, alone and in combination, differ in their effect on bone mass, biomechanical strength, and uterus in ovariectomized nude mice with MCF-7 human breast tumor xenografts.
Power KA, Ward WE, Chen JM, Saarinen NM, Thompson LU.

Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada.

In our previous study, flaxseed (FS) reduced while soy protein isolate (SPI) stimulated MCF-7 breast tumor growth in ovariectomized mice. In addition, combining SPI and FS resulted in a negation of SPI-induced tumor growth. In this study, the effects of SPI, FS, and their combination were further examined on mouse bone and uterus to further ensure overall safety of the breast cancer treatments. Ovariectomized mice with established MCF-7 xenografts were fed either a basal diet (control), or a basal diet supplemented with 10% FS, 20% SPI, or SPI + FS for 25 wk. Mouse bones were analyzed for mineral and biomechanical strength properties, and uterus weight was measured. The SPI group had a higher femur bone mineral density and biomechanical strength parameters (yield load, stiffness, and peak load) compared to control, while the FS group significantly increased femur stiffness and peak load. The SPI + FS group did not affect femur mineral, but significantly reduced whole femur area and length and increased femur yield load, stiffness, and peak load. Uterus weight was significantly increased by the SPI + FS group, while SPI alone induced an intermediate effect. In conclusion, all dietary treatments induced beneficial effects on bone in a preclinical mouse model of postmenopausal breast cancer. Although the SPI + FS and SPI groups exerted stimulatory effects on uterus weight, other histological parameters need to be measured to determine the overall safety of these breast cancer treatments on the uterus.