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Soy and isoflavones

Soybeans are the richest dietary source of isoflavones. Isoflavones belong to the group of phytochemicals and are being studied intensively because they extent physiological effects which may help reduce the risk for certain diseases. Epidemiological studies have indicated that populations which regularly consume soyfoods have lower incidences of breast, colon and prostate cancers. The incidence is particularly low for hormone-dependent cancers. In Asian countries, where the prevalence of disorders such as breast cancer and invasive prostate cancer is relatively low, people consume soy foods in amounts that provide on average 50-100 mg of soy isoflavones a day.

Studies show that isoflavones account for approximately three-fourths of soy's protection, while its protein is responsible for about one-fourth.
Soy products have different isoflavone contents. Whole soy products like soymilk, tempeh or soy flour have high concentrations of isoflavones. Products isolated from soybeans have varying amounts of isoflavones, depending on how they were processed. Soybeans contain three types of isoflavones in four chemical structures. Chemical analysis of a wide variety of soyfoods have shown a great difference in amounts of the isoflavones as well as their chemical forms. The variety of soybean grown, growing conditions, location and crop year, can all make a difference in the amount of isoflavones in soybeans.

The best way to consume isoflavones is in food form, so that you can benefit from all of soy's nutrients and beneficial compounds. If you decide to take supplements, choose products that supply a mixture of isoflavones including genistein and daidzein. Try to ingest a total of 100 mg isoflavones a day from supplements, foods, or a combination of the two.

Isoflavones are fairly stable, so under normal home or institutional cooking methods isoflavones are not destroyed.

Another important plant source of isoflavones is red clover.


What effect do the isoflavones have on men?

What effect do the isoflavones have on men? Does it result in decreased sex drive or growth of breast tissue?
Guest - 02/04/2012

What effect do the isoflavones have on men?

Isoflavones do not decrease sex drive nor do they cause the growth of breast tissue. These are rumours created and spread by some soy bashers. Actually they are healthy, even for men.
Rob - 02/04/2012

What effect do the isoflavones have on men?

High estrogen levels in men are associated with breast cancer. Unfortunately the studies looking for something bad when consuming soy are not being done or given any media attention as soy has become touted by even the FDA as a wonder food. It is not and shouldn't be consumed by anyone until it is thoroughly studied with human feeding trials (not just the random uncontrolled consumption that is currently going on with the public). Soy should never be consumed by males until it is known what action occurs when they ingest this hormone-like substance.The fact that soy flavinoids are used in the menopausal pill Estroven should be a clear warning for males and children to NOT eat any soy product. Michael Polidori
michael0156 - 04/04/2012

Soy products and HRT medication

Is it advisable to take soy products whilst taking HRT medication? Thank you Pamela.
Pamela - 11/11/2013

Soy products and HRT medication

You should first consult with your own doctor about you specific situtation. Studies indicate that you can take soy products while taking HRT. It is unlikely that you can overdose on estrogen by adding natural soy products, such as soy milk, tofu and tempeh, to your diet. But I would not recommend taking supplements with high isoflavones content, unless recommended by your doctor. Soy is a good source of phytoestrogens, estrogen-like compounds from plants. Phytoestrogens are not estrogen; in some ways and in some tissues of the body, they act like estrogen (decreasing hot flashes and lowering total cholesterol, for example), but in other areas, they act the opposite way (in the breast, perhaps, which may lower risk of breast cancer). Some women healthcare leaders are calling soy the perfect alternative to HRT.
Hildegard - 11/11/2013

Unfermented soy

Hi I was just reading a few articles that said if the soy nuts are made of unfermented soy this is actually detrimental to your health. Apparently the isoflavones become harder to process and they contain phytic acid which is an anti nutrient that binds to iron and other nutrients and prevents absorption. You may be aware of this already but if not I highly recommend reading up on the difference between unfermented and fermented soy products.. Also unless you have a weight problem the fats in nuts are quite good for you like with avocado which actually help the absorption of things like beta carotene. Hope that may be useful.
Paul - 24/10/2014

soy milk- precocious puberty

I find this information very interesting. I was a firm believer in soy milk since my young daughter was lactose intolerant. SHe is 10 years old now and was on soy milk for approximately 4 years. Soy milk does affect the body!! It made her go thru puberty at a young age. But I must agree it is very difficult to find info about the negatives effects of soy milk. My daughter is living proof that soy milk does harm. Proof as well are the other ladies on this site that has had to undergo therapy for various forms of thyroid problems. People will realize at some point soy milk is harmful and especially when it harms a young one .
Niki - 28/06/2016

soy milk- precocious puberty

There many molecules in our food and environment that might cause precocious puberty. These molecules include pesticides, components in plastics and hormones in meat.

Most studies about the effect of soy on puberty have been conducted on rodents. One study that involved children concluded that that long-term feeding with soy protein formula in early life does not seem to produce estrogen-like hormonal effects ("Soy protein formulas in children: No hormonal effects in long-term feeding." J Pediatr Endocrinol Metab. 2004 Feb;17(2):191-6).
Rob - 01/08/2016

soy milk- precocious puberty

Soy products during infancy tend to increase the frequency of early onset puberty in females and homosexuality in males. The dynamics of this relationship have been studied as far back as the 1970's in laboratory animals. I discovered this relationship while performing research as a freshman biology student in 1977.
The soy products interfere with the normal production and conversion of testosterone to CNS estradiol in the male infant, which is necessary for induction of male-specific neuro-differentiation. This obstruction of normal CNS neuro-differentiation prevents the "neutral female brain" from induction to a "normal male brain." Soy milk products have a profound impact on interfering with the neuro-differentiation process. In females it may lead to early puberty; and in males it may lead to homosexuality. The alteration in normal brain development is permanent. Testosterone and estrogen are profoundly involved in early neuro-endocrine development. Infants should not be consuming substances known to mimic the affects of a human hormone, such as estrogen.
Guest - 05/08/2016

soy milk- precocious puberty

I hardly say soy milk is doing any harm at all. I just starting drink soy milk and I'm 21 years old. My during my whole childhood i drank 2% milk, i doubt soy milk causes early puberty because I started at age 11 which is not early consider i was the late one among my fellow peers at the time, and i laugh at the fact that someone even considers soy milk to "cause" homosexuality. I do in fact agree on not putting hormones in any product at all, in fact i think products should make whether or not there are any hormones in products.

I believe this is a marketing rumor for people who look for something to be wrong with the children when there's really not. soy vs. dairy only really matters if you 1 allergic 2 weight watching or 3 you simply prefer to drink soy for taste nothing wrong in that.
Guest - 22/08/2016

Soya milk

My daughter was given soya milk from the age of 2, and by 5 she had a breast bud appear. The only conclusion we could come to was that it was linked to the soya milk. We stopped the soya milk, and 6 months later the breast bud had reduced in size. I am absolutely convinced that the soya milk caused the onset of puberty.
Nicola - 11/10/2017


soyaproducten bevatten plantaardige oestrogenen. Daardoor zijn ze tegenaangewezen voor kankerpatiënten die op oestrogenenafbouwmedicatie staan. U MOET dit melden op al uw producten !!!
De Wit - 16/11/2017

Soya milk

With respect, I had a very interesting conversation with a friend of mine today, who after I explained I had cut down on dairy products and was now using Soya, warned me as a dietician, that she had looked into soya addition in our diet and that it was prone to hormonal imbalance!! wow I explained, I read somewhere that drinking an amount of soya milk per day for a few months would lessen the stored fat around ones middle as one gets older, and yes I had lost weight, but the disturbing thing was I explained, is that when I had dieted before normally and had been for years the weight would leave my breasts first, on this diet of soya I have found myself with larger breasts than normal and could not understand why!!! I now find this very disturbing and have ousted any soya milk that I had left, and will in the future stay clear, I will continue on my quest and watch my diet as always. Confused?? Watch this space.
Barbara - 24/11/2017

Soy Milk & Early Puberty

My 7.1 year daughter is allergic to milk. She has been drinking soy milk for three years and now has gumball sized lumps under her areolas! The doctor said she is starting puberty! She only weighs 43 lbs and is the height of a 5 year old. We were told to stop giving her soy milk. I hope it stops the symptoms. :( I hope to warn other parents.
Guest - 25/02/2018

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