Phytoestrogens (isoflavones) are attributed with all the numerous benefits of soy and its derived products: treatment and prevention of cardiovascular diseases, osteoporosis, cancer, age-related cognitive disorders, as well as unpleasant menopausal symptoms in women…
We have already discussed the exceptional harm of soy and soy protein isolate – the most popular form of soy in modern food industry.
Now let’s talk about the benefits and harms of phytoestrogens primarily for women over 40, in combating menopausal symptoms.
Main thoughts:
What are phytoestrogens?
Phytoestrogens are plant compounds that are very similar in action to estrogen – the female sex hormone 24.
They are found in a wide variety of plant products: soybeans, flaxseeds, whole grains, legumes, fruits, and vegetables 25.
Phytoestrogens have recently attracted the close attention of pharmacists and naturopaths. This is explained by the important role of estrogen in the human body, the action of which they “mimic.” Estrogen is responsible for 12:
- the growth and functioning of reproductive organs in women;
- the health of the bone and nervous systems;
- the health of the cardiovascular system.
Scientists, pharmacists, and manufacturers are interested in phytoestrogens primarily as a natural remedy for addressing hormone-dependent issues during menopause in women over 40-50 years old, in whose bodies changes occur at the level of the reproductive organs and the skeletal system.
Phytoestrogens are plant compounds that resemble the female sex hormone estrogen in their properties.
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Content of phytoestrogens in food products
Phytoestrogens enter our bodies through food. Moreover, soy is not the only source of them.
Sources of phytoestrogens include:
- herbs and spices (garlic, parsley);
- grains (wheat, rice);
- vegetables (soybeans, beans, carrots, potatoes);
- fruits (dates, pomegranates, cherries, apples);
- beverages (coffee).
The population of Asia, as is known, consumes a large amount of soy products compared to the populations of Western countries. Statistics show that Asian women significantly suffer less from breast and endometrial cancer (the inner layer of the uterus), and menopause occurs much more gently for them, with a lower risk of osteoporosis 17.
On the other hand, when Asian women emigrate to Western countries, they experience an increased risk of various diseases, as their diet undergoes changes: the amount of fats and proteins increases, while the share of fiber and.. soy decreases 18.
Phytoestrogens are represented in food products in three main classes:
- isoflavones, with soy and soy products being the main sources; they are also found in other legumes, but in significantly lower concentrations;
- lignans, found in seeds, whole grains, berries, fruits, vegetables, and nuts;
- coumestans, found in broccoli and Brussels sprouts.
Despite the fact that isoflavones are most often discussed (their benefits and harms), lignans are found in higher concentrations than isoflavones in the diets of representatives from the USA and Europe 19.
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The table presents the content of phytoestrogens in various products: the total amount of different types of isoflavones (genistein, daidzein, and glycitein) per 100 g of the product. A complete table for all products, as well as a breakdown by different types of phytoestrogens, can be found on the website of the U.S. Department of Agriculture 13.
| Phytoestrogen Content in Food Products | |
|---|---|
| Product | Total Phytoestrogens (Isoflavones), mg/100 g |
| Green soybeans, boiled and dried | 19.3 |
| Green soybeans, raw | 120 |
| Soybeans, mature seeds, sprouted, steamed | 12.5 |
| Soybeans, mature seeds, sprouted, raw | 107 |
| Miso | 3-100 |
| Natto | 46-124 |
| Soy mozzarella | 0.9-7.7 |
| Soy flour | 73-324 |
| Soy lecithin | 15.7 |
| Soy protein concentrate (water-washed) | 61-167 |
| Soy protein concentrate (alcohol-washed) | 2-32 |
| Soy protein isolate | 47-199 |
| Soy infant formula | 2-30 |
| Soy mayonnaise from tofu | 16.8 |
| Red clover | 21 |
We did not randomly mention clover among the variety of soy products.
This beautiful field grass attracted the attention of scientists to phytoestrogens back in the distant 1940s when it was discovered in Australia that sheep grazing in clover fields experienced reproductive dysfunction: a decrease in the number of lambs born, lactation issues, and changes in reproductive organs leading to complete infertility 15,16.
What explains the variation in phytoestrogen concentration in the same types of soy products?
This is largely determined by the method of processing and growing conditions. It is known that they can be almost completely removed by washing with ethyl alcohol, but this procedure is costly and not often used by manufacturers.
Sources of phytoestrogens are plant products: they are most abundant in soy, but they are also found in other legumes, herbs, fruits, and vegetables.
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Bad Start: The Entry of Soy Phytoestrogens into the Market Began with Deception
Let’s start with a little-known backstory of the penetration of isoflavones into the market, which eloquently indicates that “not everything is right with them.”
As is known, Western countries, particularly the USA, set the tone for everything happening in the world. The official endorsement of soy, soy protein isolate, and soy isoflavones as revolutionary food products began precisely in the USA.
Look at the statement from one of the advocates of soy:
“The path to the official approval of soy products by the FDA (U.S. Food and Drug Administration) was long and complicated, consisting of a detailed analysis of clinical studies gathered from more than 40 scientific works conducted over the last 20 years.
Soy protein turned out to be that rare product backed by a large number of scientific evidence of its health benefits, sufficient not only to obtain official approval and recommendation for consumption but also to pass a rigorous approval process.” 11.
Both scientific research and official approval are mentioned.
However.
In 2000, researchers
They found that the “long and complicated” path to the official endorsement of soy consisted of a blatant deception.
The issue of legalizing soy was handled by Protein Technology International – the largest soy producer in the USA. The initial wording of the request addressed to the FDA was a demand to confirm the health benefits of soy isoflavones – substances that act similarly to the female sex hormone estrogen and are abundantly found in soybeans.
The initial premise of the representatives of this company was that “only soy protein, in which the isoflavones remained intact during processing, is beneficial for lowering blood cholesterol levels.“
After some time, FDA representatives (most likely for a reward) changed the wording of the request, removing any mention of “soy isoflavones” and replacing it with “soy protein,” which is categorically prohibited.
What was this related to?
It was related to the fact that a number of researchers, including scientists hired by the U.S. government, provided numerous facts indicating that isoflavones are toxic to the human body.
The legalization of soy phytoestrogens began with a deception that consisted of substituting terms in the official request for permission to sell them, after scientists discovered their exceptional harm.
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The Harm of Phytoestrogens.. in Parrots
The facts about the harm of phytoestrogens listed below are taken from a large-scale study on the harm of soy by scientists , published in Nexus magazine, Vol. 7, No. 3 in 2000, and are also described in the book The Whole Soy Story: The Dark Side of America’s Favorite Health Food, available in a paid English version on amazon.com.
Male individuals of some species of tropical birds are born with a monochromatic (dull) coloration, and they only acquire colorful plumage at the time of sexual maturity (between 9-24 months).
In 1991, Richard and Valerie James, bird breeders from New Zealand, purchased a new type of feed for their birds – based on soy protein 1. The result – their birds reached sexual maturity (acquired bright coloration) just a few months later!
The feed manufacturer commented on this fact as one of the advantages of the feed they produced.
In 1992, feeding an Australian parakeet with this feed, which usually acquires beautiful red plumage at 18 – 24 months, had a stunning and at the same time frightening effect – it turned red already at 11 weeks (in the 3rd month!).
In the following years, birds that reached early sexual maturity showed a decrease in reproductive ability, and those chicks that did appear were deformed, stunted, and often died before reaching maturity, especially among female individuals. As a result, the overall number of birds in the aviary decreased.
Birds exhibited beak and bone deformities, dysbiosis, immune system disorders, pathologies, and aggressive behavior.
Autopsy revealed that their digestive organs were literally “falling apart.” The list of problems was very similar to those observed in the two children of the researchers who were fed soy-based formulas.
Frightened, the researcher hired a toxicologist for further study.
As a result of the analysis of scientific literature, numerous confirmations were found that soy consumption leads to sad consequences: infertility, cancer, and leukemia among children, as well as that the phytoestrogen genistein from soy provokes thyroid dysfunction in animals 2.
The consumption of soy is associated with infertility, an increased risk of cancer and leukemia in children, and thyroid dysfunction.
The doctor also studied bird feed and found that it contained high amounts of the phytoestrogen genistein. When the birds were no longer fed soy protein isolate-based feed, the flock gradually returned to normal levels.
Scientists clearly understood that it was necessary to warn the public and government officials about the toxins in soy products, especially regarding phytoestrogens/isoflavones, which adversely affect the endocrine system.
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The harm of soy phytoestrogens to humans
The mortality of parrots in the aforementioned example was not the biggest problem.
It turns out that the researchers, unknowingly, were simultaneously conducting an experiment on their own children, who were fed soy formulas: they exhibited defects similar to those of the parrot chicks.
In 1991, Japanese researchers reported that consuming just 30 grams (two tablespoons) of soybeans per day for only one month led to a significant increase in the secretion of a certain hormone affecting thyroid function 3.
Other deviations in thyroid function were also observed; many patients complained of constipation, fatigue, and lethargy, even if their iodine intake was adequate.
In 1997, researchers from the National Toxicology Center of the USA made the unpleasant discovery that the cause of thyroid dysfunction was the same components of soy – phytoestrogens 4.
One scientific study showed that for an average-aged woman, a dose of just 45 mg of phytoestrogens was enough to cause thyroid dysfunction. Even after stopping soy consumption, the dysfunction persisted for three months 5.
25 grams of soy protein isolate – the minimum recommended amount by Protein Technology International to achieve a cholesterol-lowering effect – contains between 50 to 70 mg of phytoestrogens.
One hundred grams of soy protein (the maximum recommended amount to achieve a cholesterol-lowering effect) can contain nearly 600 mg of phytoestrogens 6 – an amount that is undoubtedly toxic.
In 1992, the Swiss health service estimated that 100 grams of soy protein per day provides an estrogenic equivalent found in hormonal pills 7.
100 grams of soy protein contain an equivalent of the female sex hormone estrogen equal to one hormonal tablet
Laboratory studies have also shown that phytoestrogens inhibit the synthesis of steroid hormones 8 responsible for muscle growth.
Infertility, thyroid and liver diseases due to the consumption of soy protein (phytoestrogens) have been observed by researchers in several animal species, including mice, cheetahs, quails, pigs, rats, sturgeons, and sheep 9.
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Phytoestrogens during menopause for women over 40…
Isoflavones are also attributed with a “beneficial effect” on menopause symptoms in women over 40, including a reduction in the frequency of “hot flashes,” protection against osteoporosis, normalization of blood pressure, etc.
During menopause in women (after 40-50 years), the level of estrogen significantly decreases, accompanied by characteristic unpleasant symptoms:
- “hot flashes”;
- night sweats;
- sleep disturbances;
- migraines;
- frequent mood swings without reason;
- increased heart rate;
- increased sensitivity and nervous excitability;
- worsening skin condition, appearance of wrinkles;
- general malaise, weakness;
- shortness of breath and feeling of lack of air;
- dizziness;
- nausea;
- weight gain;
- decreased libido;
- dryness and itching in the vagina.
The greatest concern for women is caused by the so-called “hot flashes” – sudden redness of the face, neck, chest, and back of the head, accompanied by a feeling of heat and profuse sweating 26.
The listed menopause symptoms significantly affect the quality of life of women. There are several ways to combat them:
- hormone therapy;
- medications to alleviate specific symptoms (e.g., blood pressure pills);
- phytoestrogens (soy isoflavones).
Hormone therapy has both advantages and risks 27: when estrogen hormone is administered, the risk of stroke and venous thromboembolism increases, and if progesterone is also administered, the risk of breast cancer and heart attack rises.
Medications only temporarily alleviate some symptoms.
Scientists are in constant search for a safer and more effective alternative.
This is where phytoestrogens come into play. Their chemical formula is very similar to that of estrogen; when they enter the body, they exert either an estrogenic or anti-estrogenic effect depending on the natural level of estrogen: when it is high – the effect is anti-estrogenic, when low – estrogenic 28.
Scientists have high hopes for phytoestrogens in treating menopausal symptoms in women.
The premise for this is the fact that women from Asia, who traditionally consume more phytoestrogens in their diet 30, experience much milder menopause than women from America and Europe 29,30.
Researchers see great potential in phytoestrogens for alleviating menopausal symptoms in women over 40 as a safe alternative to hormone therapy.
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Scientific research on the benefits of phytoestrogens/soy isoflavones for women over 40 during menopause
There are many studies on the effects of phytoestrogens on the bodies of women aged 40-50 for treating menopausal symptoms. However, their results are very contradictory: they use different doses and types of phytoestrogens, experiments are conducted differently, and their intake from other food sources is not controlled.
Scientists have not yet reached a consensus on how effective phytoestrogens are.
To understand their position, we will look at the results of just one of the recent meta-analyses of scientific works (when all available scientific studies on a specific topic are examined).
In it, researchers analyzed over 500 studies. Of these, only 15 were deemed high-quality, meeting the principles of conducting scientific experiments.
The average age of the female participants ranged from 48 to 60 years, with the number of women from 30 to 250, and the duration of phytoestrogen/isoflavone intake from 3 to 12 months.
So, what conclusions did the scientists draw:
- Of the seven studies that investigated the effect of phytoestrogens on the Kupperman index, three noted a significant reduction, while four showed no effect.
- A reduction in the frequency of “hot flashes” in women who took phytoestrogens was noted in four out of ten studies; in the other six, there was no effect.
- No side effects from taking phytoestrogens were reported.
Conclusion of the scientists:
“Phytoestrogens are widely used during menopause by women over 40-50 years old; however, the existing scientific studies present very contradictory results regarding their effectiveness.
More thorough research is needed on the potential long-term side effects of phytoestrogens, particularly their impact on cardiovascular diseases, breast cancer, venous thromboembolism, and stroke.
Scientific studies on the benefits of phytoestrogens for women during menopause are very controversial: about half of the experiments show some effect, while the other half do not.
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The Benefits of Phytoestrogens for the Treatment and Prevention of Osteoporosis
Osteoporosis is one of the most common women’s diseases of our time.
The lack of estrogen that accompanies menopause is generally not considered one of the main risk factors for osteoporosis, but it is indirectly related to many recognized factors: female gender, slender body type, advanced age, menopause, amenorrhea, and excessive alcohol consumption.
As early as 1940, it was suggested that estrogen is important for preventing osteoporosis, as it affects calcium concentration in bones 20,31. This was confirmed in 1970 when a method for measuring bone density was invented 21.
The dangers of hormone therapy have already been discussed above. As for the benefits of phytoestrogens for the treatment and prevention of osteoporosis, the results of scientific studies are also contradictory.
Here is what scientists say:
“The results of several studies on the benefits of phytoestrogens, particularly soy isoflavones, for bone health are contradictory and insufficient to draw definitive conclusions… the available data is not enough to recommend their widespread use.” 21
“The intake of phytoestrogens negatively affects breast growth and lactation, and increases the risk of uterine diseases, such as fibroids and endometriosis. Moreover, the consumption of phytoestrogens causes non-viral hepatitis and uterine cancer.
The effect of phytoestrogens is determined by the concentration of estrogen receptors, as well as the levels of other hormones in the body. There is insufficient scientific data to recommend them in specific doses.
The effectiveness of phytoestrogens is unclear, as is their safety for health with long-term use. It is evident that phytoestrogens may be beneficial in combating osteoporosis, but they also increase the risk of side effects.” 23
Here is the conclusion of the authors of a large-scale study on the harm of soy, to which phytoestrogens are attributed the ability to combat osteoporosis:
“The conclusion about the benefits of soy for the treatment and prevention of osteoporosis has been largely drawn from the fact that Asians, whose diet includes a significant amount of soy products, suffer much less from this disease.
In essence, the claim that soy prevents osteoporosis is sensational, considering the fact that soy products block calcium and cause a deficiency of vitamin D.
If Asians indeed have lower rates of osteoporosis than people in Western countries, it is only because their diet contains a higher amount of vitamin D from lard, shrimp, and other seafood, as well as a greater amount of calcium from broths made from bones.
The reason that Westerners have such high rates of osteoporosis is that they have replaced butter – a traditional source of vitamin D and other fat-soluble active components necessary for calcium absorption – with soy.“
Scientific research on the benefits of phytoestrogens for the prevention and treatment of osteoporosis during menopause is very controversial: scientists say that some effect is possible, but also warn of a high risk of side effects.
