T Nation

Soy is the shit!


#1

Oops, I mean soy IS shit. :slightly_smiling: Here are some recent abstracts that I thought some of you may or may not enjoy.
: J Endocrinol 2001 Sep;170(3):591-599 Related Articles, Books, LinkOut

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.


Weber KS, Setchell KD, Stocco DM, Lephart ED.

Neuroscience Center, Brigham Young University, Provo, Utah 86402, USA.


Nutritional factors, especially phytoestrogens, have been extensively studied for their potential beneficial effects against hormone-dependent and age-related diseases. The present study describes the short-term effects of dietary phytoestrogens on regulatory behaviors (food/water intake, locomotor activity and body weight), prostate weight, prostate 5alpha-reductase enzyme activity, reproductive hormone levels, and testicular steroidogenic acute regulatory peptide (StAR) levels in adult Sprague-Dawley rats. Animals were fed either a phytoestrogen-rich diet containing approximately 600 &mgr;g/g isoflavones (as determined by HPLC) or a phytoestrogen-free diet. After 5 weeks of consuming these diets, plasma phytoestrogen levels were 35 times higher in animals fed the phytoestrogen-rich vs phytoestrogen-free diets. Body and prostate weights were significantly decreased in animals fed the phytoestrogen-rich diet vs the phytoestrogen-free fed animals; however, no significant change in prostate 5alpha-reductase enzyme activity was observed between the treatment groups. Locomotor activity levels were higher in the phytoestrogen-rich vs the phytoestrogen-free animals during the course of the treatment interval. Plasma testosterone and androstenedione levels were significantly lower in the animals fed the phytoestrogen-rich diet compared with animals fed the phytoestrogen-free diet. However, there were no significant differences in plasma LH or estradiol levels between the diet groups. Testicular StAR levels were not significantly different between the phytoestrogen-rich vs the phytoestrogen-free fed animals. These results indicated that consumption of dietary phytoestrogens resulting in very high plasma isoflavone levels over a relatively short period can significantly alter body and prostate weight and plasma androgen hormone levels without affecting gonadotropin or testicular StAR levels. The findings of this study identify the biological actions of phytoestrogens on male reproductive endocrinology and provide insights into the protective effects these estrogen mimics exert in male reproductive disorders such as benign prostatic hyperplasia and prostate cancer.

PMID: 11524239 [PubMed - in process]


#2

Yonsei Med J 2001 Aug;42(4):395-404 Related Articles, Books

Development of rat prostatitis model by oral administration of isoflavone and its characteristics.

Kwon SM, Kim SI, Chun DC, Cho NH, Chung BC, Park BW, Hong SJ.

Department of Urology, Yonsei University College of Medicine, C.P.O. Box 8044, Seoul 120-752, Korea. sjhong346@yumc.yonsei.ac.kr


Inflammation of the prostate can be induced experimentally in rats by the subcutaneous administration of estrogen. However, it is usually achieved at the price of some alteration in the sex steroid hormone balance and morphological changes in the prostate. In this study, a soy-extracted isoflavone mixture with weak estrogenic activity was administered orally in an attempt to induce prostatitis in a more physiologic way and to characterize the inflammation induced. A total of 36 male Sprague-Dawley rats, 8 weeks old, were divided into 2 groups. The control group was fed with only an AIN-76A diet containing no detectable phytoestrogen and the experimental group was fed with AIN-76A and a soy- extracted isoflavone mixture (genistein 60.0% and daidzein 19.6%), 300mg/kg body weight for 9 weeks. The sequential body weight and prostate weight at necropsy were measured. A histologic examination and histomorphometry assessed the changes in the prostate. The serum concentrations of testosterone and dihydrotestosterone were measured to estimate the effects on the androgen level. Intraprostatic concentrations of genistein and daidzein were measured by gas chromatography/ mass spectroscopy (GC/MS). While no sign of prostate inflammation was apparent in the control group, severe inflammatory changes in the stroma, increased epithelial detachment and inflammatory exudates within the glandular lumen of the dorsolateral prostate were observed in more than 80%(15/18) of the experimental group. However, there was no significant difference in the ventral prostate between the two groups. The daidzein and genistein concentrations in both the lateral and ventral prostates were significantly higher in the experimental group than in the control group where no isoflavone was detectable. In addition, the concentrations were much higher in the dorsolateral than in the ventral prostate. Although the body weight gain was not consistent in the experimental group, there were no significant differences in the prostate weight and serum androgen level between groups. In summary, when a soy-extracted genistein and daidzein-rich isoflavone mixture was administered orally into rats, prostatic inflammation with characteristic lobe specificity developed. The present method of inducing prostatitis seems to be a more physiologic than an estrogen-induced experimental model, and sequential pharmacokinetic studies might help in establishing this model as a more valuable tool in assisting future research in this field.

PMID: 11519081 [PubMed - in process]


#3

Gee Cy, I guess you couldn't wait to post all this in an article.


#4

What sucks is because of that KNUCKLE-HEAD Dan Duchaine
and his radical ideas, a few years back I was swallowing a "ton"
of genistein and daidzein in order to fight estrogen.
Question: Do the effects of massive doses of soy wear off
after a few years? I ask this because my "T" levels have declined
BIG TIME ever since. Or could I just be getting older?!
HELP! Joey Z.


#5

I can't say in total confidence that those isoflavones caused permanent reductions in testosterone but I can't dispel the idea either. I'd need more information from you in order to have a clue.


#6

I've never had my numbers checked. My HMO deemed it an extravagance
for someone of my age and apparent physical condition to be tested.
I'm using my decline in sexual appetite and function as a yardstick.
In my estimation, the decline happened all too quickly. It also takes a little
longer to recover from my workouts lately. I was using Twinlabs Mega
Soy for about 6 months (about 6 caps per day). Each cap contains 39mgs
of genistein and 34mgs of daidzein.

Funny thing: I inquired about a prescription for Armidex from my family Doc,
but all I got was a BLANK STARE; guess he never heard of it. Then I asked
about Clomid. His response was that I didn't need it unless I was planning to
ovulate. My kingdom for an elightened physician!!!


#7

I Forgot to mention that I consumed well over a pound a week
of soy based protein powder for almost a year. This was between
3 to 4 years ago.(Mostly Twin Labs Veggie Fuel.)


#8

I'd have to see a hormonal profile before I could make any assumptions. Sorry, your "feel" can be an indicator but it doesn't confirm anything.