As has been suspected by many in the natural health community for a while, research from the University of Illinois has confirmed that the concentration of
soy isoflavone in supplements may help drive tumor growth in women with estrogen - receptor positive breast cancer.
There are a variety
of isoflavones in soy, but several of the main ones are biologically inactive until they hit your intestinal tract (specifically, these compounds are activated by your intestinal bacteria).
This amount is equivalent to the amount of soy
isoflavones in 500 milliliters of soy milk.
Soy
contains Isoflavones which are estrogen - like compounds that have been shown to reduce ovulation and stimulate the growth of cancer cells.
By comparison, the average level of the soy
isoflavone genistein in the bloodstream of Asian women is approximately 25 nanograms per milliliter, but in U.S. women, only 2 nanograms.
Soy milk is widely consumed for its health benefits linked to the anti-carcinogenic properties of phytonutrients present in the milk known
as isoflavones.
Our findings suggest that survival may be better in patients with a higher consumption of
isoflavones from soy food,» John said.
Studies on the effects of
isoflavones on human estrogen levels are conflicting, and it's possible that they affect people differently.
Isoflavone supplements contain much high concentrations of estrogen - like phytochemicals than whole soybeans do.
By longitudinal mixed - model regression analysis, bone mineral density increased 0.26 % per 1 mg of
isoflavone intake per year.
For comparison, the total
isoflavone content in mg in 100 g of some soy foods: tempeh 60.61 edamame 48.95 tofu 30.41 soymilk 10.73
Keep soy intake to a minimum (as it contains phytoestrogens
called isoflavones which mimics the activity of estrogen in the body) 6.
Two or more servings of such foods would provide 60 - 100 mg
isoflavones per day, an amount that provides the estrogen equivalent of the contraceptive pill2 and one that clearly poses dangers after only a brief period of daily intake.
Specifically, soy protein isolates contain
isoflavones which can interact with hormones like estrogen and potentially skew hormone levels when taken in excess.
A large study of 403 postmenopausal women found that taking soy
isoflavones for two years, in addition to calcium and vitamin D, significantly reduced the loss of bone density that occurs during menopause (37).
The second broad group are the flavonoids, including
isoflavones found in soy, anthocyanidins found in berries and wine, flavones found in herbs, flavonols found in broccoli, tomato and tea, flavanones found in citrus fruits and juices, and flavan -3-ols found in cocoa, tea and wine.
Minerals like calcium in soy foods can become more soluble and bioavailable through fermentation as can the bioavailability of many phytonutrients,
including isoflavones like genistein and daidzein.
However, the authors note that
dietary isoflavone intake was correlated with socioeconomic and lifestyle factors, which may also play a role in lowering mortality.
The innovative fermentation technique also enriches the drink
with isoflavones, which are antioxidants that have many health benefits.
Messina M and Redmond G. Effects of soy protein and
soybean isoflavones on thyroid function in healthy adults and hypothyroid patients: a review of the relevant literature.
«At the population level, we see an association between
isoflavone consumption and reduced risk of death in certain groups of women with breast cancer.
In fact, nearly half (48 %) of the women
taking isoflavones experienced hot flashes compared with just 31 % of women who took the placebo!
They concluded that the soy
isoflavone extract exerted favorable effects on vasomotor symptoms and good compliance, providing a safe and effective alternative therapeutic for postmenopausal women.
It's also important to note that multiple studies (also here and here) have found neither soy nor
isolated isoflavones cause an increase in breast density, which is really what we man boob sufferers are worried about.
The average
total isoflavone intake among soy users in this study was 3.4 mg / day, much lower amounts than reported in other studies.
It has been argued that high levels of soy
isoflavones such as genistein, daidzein and genistin in Asian diets protect the inhabitants of Japan and China from certain degenerative diseases, especially breast and prostate cancer.
For example, rodents
consuming isoflavones have fewer tumors and / or a delay in tumor development in mammary, liver, colon, and prostate cancer (9, 10, 11, 12).
Studies have shown that soy
isoflavones increase bone mineral density in postmenopausal women, suggesting that soy consumption may reduce the risk of osteoporosis.
A recent study found that babies fed soy - based formula had 13,000 to 22,0000 times
more isoflavones in their blood than babies fed milk - based formula.
The association
between isoflavone intake and reduced mortality was strongest in women with tumors that lacked estrogen and progesterone receptors.
Compositional changes in trypsin ihibitors, phytic acid, saponins and
isoflavones related to soybean processing.
The starch in legumes would cause the same digestive problems as rice cereal and the endocrine
disrupting isoflavones in tofu would be a disaster for baby's delicate and developing hormonal system.
(18 - 20) Soy
isoflavones cause significant endocrine disruption both directly and indirectly: directly by binding with estrogen receptors, and indirectly by interfering with the body's production of estrogen, testosterone and other hormones.
Metabolism of the soy
isoflavones daidzein and genistein by fungi used in the preparation of various fermented soybean foods.
In another study, it was found that soy
isoflavones given to a control group resulted in interrupted or absent periods.
Also, menopause increases a woman's risk for developing osteoporosis (significant bone loss) and some studies suggest that a proprietary extract of red
clover isoflavones may slow bone loss and even boost bone mineral density in pre and peri-menopausal women.
Like TPO activity, uptake of iodine into the thyroid cells by NIS can be interfered with
by isoflavones.
However, there is no consensus amongst scientists that
isoflavone ingestion reduces breast cancer risk.
Professor M. Monica Giusti of The Ohio State University has done research on soy
isoflavones appearing in commercial egg yolks.
Because of this double effect, it remains unknown
whether isoflavone consumption should be encouraged or avoided by breast cancer patients.
The
main isoflavone in soy, genistein, deactivates human thyroid peroxidase (TPO), an enzyme, and interferes with T3 and T4 synthesis.
«In the first study to examine the connection, we found women who consumed soy
isoflavones regularly saw improvement in biological markers that reflect how effectively the body utilizes insulin to process sugars and had reduced levels of harmful cholesterol.»
Since estrogen receptors are expressed in the brain, it's no surprise that dietary
isoflavones affect behavioral parameters.
Dr. Pepine and his colleagues had expected that women with high levels of genistein (the
primary isoflavone found in soybeans) would show improved vascular health, but found the opposite to be true.
Phrases with «isoflavones»