effects of phytoestrogens in soy?

[kylecortez]

RRM, you know your biochem, so i wanted to know what you know personally about the phytoestrogens in soy. Do they exert estrogenic effects and supress testosterone activity? Some sites say it's only minor. I really have no idea anymore. Could you help me out? Thanks!
-Kyle

[RRM]

...the phytoestrogens in soy. Do they exert estrogenic effects and supress testosterone activity? Some sites say it's only minor.

They are right that their estrogenic activity is quite low, but that is actually not the issue. In fact, if their estrogenic activity would be equal to that of estrogen produced inside the body, they would be less bad.
That is because one part of their bad effect is that their activity is less than that of natural estrogen, while they replace that natural estrogen and this DOES have a strong effect on our hormone metabolism. Tests have shown that consuming high amounts of soy increases the level of some hormones (DHEA-sulphate), whereas in women consuming soymilk for 3 months estradiol level can already decrease by 27%.
Both daidzeine and genisteine (phyto-estrogens in soy) damage sperm cells. (1)
It has been shown in test animals that consuming soy can cause infertility. (2)
Also, the main phyto-estrogen in soy, genisteine, is mutagenic. (3)

(1) Anderson, D. et al, Effect of various genotoxins and reproductive toxins in human lyphocytes and sperm in the Comet assay. Terat. Carcinog. Mutagen. 1997 / 17 (1) / 29-43.
(2) Zimmerli,B. en J.Schlatter, Sojamilch : Gefahr durch Phytohormone ?, Mitteilungen aus dem Gebiete der Lebensmittelhygiene, 1997 / 88 / pag.219-231. , Adams, N.R., Detection of the effects of phytoestrogens on sheep and cattle. J. Anim. Sci. 1995 / 73 (5) / 1509-1515.
(3) Morris, S.M. et al, p53, mutations, and apoptosis in genistein-exposed human lymphoblastoid cells. Mutat. Res. 1998 / 405 (1) / 41-56. , Kulling, S.E. et al, Induction of micronuclei, DNA strand breaks and HPRT mutations in cultured Chinese hamster V79 cells by the phytoestrogen coumestrol. Food Chem. Toxicol. 1997 / 35 (6) / 605-613.

[kylecortez]

great response RRM. Let me ask a little more to clarify my understanding if you dont mind:

you mentioned a long time ago that estrogen in the male is necessary. its there for a reason. thats doesnt mean we need to go supplementing with estrogen of course!

do phytoestrogens tie up the the estrogen receptors on cells and prevent normal estrogen from exerting it's effect? do they have more affinity for the receptor site than estrogen itself?

I'm wondering if the body will increase estrogen production sensing that the normal estrogen it is producing is not linking up to the cells properly? Is it like insulin resistance. You know when the body detects that the insulin it makes normally is not hooking up with the downregulated insulin receptors, it's next idea is to just make more insulin.

I'm just trying to get an idea here of what happens once these phytoestrogens are introduced to the body.

-Kyle

[RRM]

thats doesnt mean we need to go supplementing with estrogen of course!

Exactly.

do phytoestrogens tie up the the estrogen receptors on cells and prevent normal estrogen from exerting it's effect? do they have more affinity for the receptor site than estrogen itself?

I believe they have the same affinity to those estrogen receptors, but the 'estrogen' effect of those phyto-estrogens on these receptors is weaker than that of estrogen made by the body. Also, they 'count' as estrogen since they do activate the receptors, so that the level of body-made estrogen will go down (estrogen replaced by phytoestrogens = same 'total estrogen')

I'm wondering if the body will increase estrogen production sensing that the normal estrogen it is producing is not linking up to the cells properly?

No, it will not, because phyto-estrogens do link up to those receptors properly. It will decrease the production of estrogen because now also 'estrogen' (phyto-estrogens) is entering the body from food.

[kylecortez]

In addition to the end of menses, significant estrogen loss can also lead to:

hot flashes and night sweats with disturbed sleep
vaginal dryness and loss of elasticity of vaginal tissue
increased urinary tract infections and problems with urinary incontinence (difficulty holding one’s urine)—although childbirth appears to be the most important cause of incontinence in postmenopausal women
loss of sexual desire and function
changes in mood, or depression
memory problems and possible increased risk of Alzheimer’s disease
breast changes—loss of firmness
skin changes—thinner skin, less collagen and moisture in the skin
loss of bone density—may eventually lead to osteoporosis
increase in cholesterol levels—may increase risk for heart disease
loss of numerous beneficial effects of estrogen on body organs and systems

RRM. These signs related to low estrogen, I wonder to myself if the high consumption of soy would demonstrate these. After all, if the phytoestorgens are tying up the receptors, then estrogen can't attach, which correlates to lower estrogen (and you even said it in time begins to be produced less). In a way, soy is behaving like an estrogen receptor blocker, right?

Also, one last thing. After menopause, when estrogen levels plummet, soy is reccomended. I wonder why an estrogen receptor blocker would be reccomened to women with low estrogen levels!!

Thanks for your help. I was intent on understanding this chemical before subsisting on this stuff in my diet.

-Kyle

[RRM]

In a way, soy is behaving like an estrogen receptor blocker, right?

In a way, but not litterally, as the phyto-estrogens do activate those receptors 'in an estrogenic way', but to a lesser extend, decreasing the influence of estrogen.

Also, one last thing. After menopause, when estrogen levels plummet, soy is reccomended.

Im not sure whether soy is specifically recommended to post-menopausal women

I was intent on understanding this chemical before subsisting on this stuff in my diet.

Ah, thats always a good thing to do!

[PepperPip]

Ok quik question becuse I am realy confused right now.

Can soy increase estergen hormones or decrese

[RRM]

I understand your confusion as soy contains estrogens (plant-estrogens), so that one might expect soy to increase estrogen levels.
However, particularly hormones are subject to feedback systems that control levels of hormones and other compounds in our body (to prevent too high and too low levels).
So, what happens is that these plant-estrogens are 'registered' as estrogens (since they interact with estrogen receptors), so that the influence of our own estrogen decreases.
Since plant-estrogens have a lower 'estrogen-activity' than the estrogens produced inside our body, overal estrogen activity decreases.

[PepperPip]

Well that is nice to know all this time I thought I was boosting my estrogen eating soy but it was jest the oppisite.
So glad I stopped