Soy, soy protein, soy protein isolate – different names for a very controversial phenomenon in the world of modern catering and sports nutrition in particular.
Soy is increasingly portrayed as an incredible benefactor of humanity, easily tackling half of the killer diseases of our time. At the same time, a considerable number of scientists studying the benefits and harms of soy are sounding the alarm, warning of serious dangers.
This article breaks the usual perceptions of soy, clearly showing that the numerous advantages of this product are nothing more than disadvantages, to which the marketing machine has added vertical strokes.
Below we will examine how soy transitioned from a technical product to being “incredibly beneficial for health,” and we will demonstrate through numerous examples that the harm of soy is mainly explained by the presence of isoflavones or phytoestrogens – female sex hormones.
Main thoughts:
The main “trump card” in the marketing of soy protein is the countless health benefits
Scientists testify that soy isoflavones are toxic to health
Soy: Evolution from a Technically Harmful Product to a “Revolutionary” Beneficial One
The extensive promotion of soy, especially in Western countries, has led to a colossal increase in its sales and widespread use. This is all the more surprising given that just a few decades ago soy was considered inedible… even in Asia.
In China, during the Zhou dynasty (1134-246 BC), soy was among the five sacred plants along with barley, wheat, millet, and rice.
However, individual drawings dating back to an even earlier time indicate that soy was originally NOT used as a food product: while images of the other four sacred plants show seeds and stems, the drawings of soy clearly emphasize the structure of the roots and their benefits.
Written sources often mention the use of soy in crop rotation, most likely as a method of enriching the soil with nitrogen [13].
Soy was not consumed until the discovery of fermentation methods, around the time of the Zhou dynasty. The first fermented soy products were tempeh, natto, miso, and soy sauce.
A little later, in the 2nd century BC, Chinese scholars discovered that a puree of boiled soybeans could be precipitated with calcium sulfate or magnesium sulfate, resulting in a soft pale curd mass – tofu or soy curd.
The use of fermented and precipitated soy products soon spread to other parts of the East, particularly Japan and Indonesia.
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The harm of soy. Facts
1 Soy contains natural toxins
Interestingly, the Chinese did not consume unfermented soybeans, unlike other legumes such as lentils, because soy contains a large amount of natural toxins or “antinutrients”.
Among them, the most notable are trypsin inhibitors – substances that hinder the action of the digestive enzyme trypsin, which is necessary for protein digestion.
That is, it turns out that soy in its natural form contains high-quality protein (with a complete amino acid profile and high digestibility), but it is very poorly digested and absorbed.
Consuming soybeans can cause serious gastrointestinal disorders and lead to chronic amino acid deficiencies in the body with corresponding health consequences, as amino acids perform a vast number of important functions.
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In experiments on laboratory animals fed a diet high in trypsin inhibitors, an increase and development of pancreatic pathologies, including cancer, were observed [14].
Also, soybeans contain a certain substance called haemagglutinin, which causes blood clot formation due to the agglutination of red blood cells.
The harmful substances in soy (trypsin inhibitors and haemagglutinin) are also growth inhibitors. In experiments on rats fed soy, persistent growth impairment was observed.
The harmful substances in soy that hinder normal growth and protein digestion are deactivated during fermentation. This is why the Chinese began to include soy products in their diet only after the discovery of the fermentation process.
During precipitation, enzyme inhibitors remain in the liquid rather than in the curd. Thus, in tofu or soy curd, the content of harmful substances that suppress growth and hinder protein digestion is significantly reduced, but not completely.
Soy also contains substances that disrupt thyroid function – goitrogens, which prevent the absorption of iodine by the thyroid.
This causes the pituitary gland to release thyroid-stimulating hormone (TSH), leading to an increase in the size of the thyroid gland and the formation of goiter [73].
2 Soy is one of the most contaminated agricultural crops
Moreover, a very large percentage of soy grown today (99%) is genetically modified and has practically the highest level of pesticide contamination compared to any other products.
Have you ever wondered why “genes are modified in soy”?
Contrary to popular belief that this is done to increase yield or something else, gene manipulation is carried out to create plants that are resistant to pesticides – chemicals used to kill weeds.
Naturally, when pesticides are sprayed, they also land on soy plants, including the beans.
Thus, in the mysterious question of GMOs, the frightening and dangerous aspect is not the altered genes of the beans, but the presence of chemical contaminants that pose serious harm to human health.
99% of soy today is genetically modified and has the highest level of pesticide contamination among agricultural crops
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3 Soy contains phytates that hinder mineral absorption
Soybeans contain a large amount of phytic acid (mainly in the bran or husk of all seeds). This substance blocks the absorption of important minerals in the gastrointestinal tract – calcium, magnesium, copper, iron, and especially zinc.
Important: The action of phytic acid is thoroughly studied today. There are hundreds of articles in modern scientific literature. Scientists generally agree that a diet based on grain-legume crops with high phytate content contributes to the development of mineral deficiencies in the body [15].
Important: Research shows that calcium, magnesium, iron, and zinc are present in sufficient quantities in plant foods consumed in these areas, but the high phytate content in grains and soy hinders their absorption.
The phytate content in soy is one of the highest compared to any other grains or legumes [16]. They practically do not break down during prolonged cooking, as occurs with other plant products [17]. Only a long fermentation process can significantly reduce them.
When soy products such as tofu are consumed with meat, the effect of phytate blocking minerals is less [18].
Important
: Vegetarians who consume tofu and soy cheese as substitutes for meat and dairy products are at serious risk of mineral deficiencies (calcium, magnesium, iron, and zinc).
Soy contains phytates, which inhibit the absorption of minerals, leading to acute deficiencies. They do not break down even with prolonged heat treatment.
Zinc is referred to as the “intellect mineral” because it is essential for the optimal development and functioning of the brain and nervous system. It plays a role in protein synthesis; participates in the mechanism of blood sugar control, protecting against diabetes; and is necessary for reproductive health.
Zinc is a key component of many vital enzymes (substances involved in digestion) and plays an important role in the immune system. Phytates in soy products inhibit the absorption of zinc more than other minerals [19].
Its deficiency can lead to an interesting psychological disorder: a false sense that some vegetarians may mistakenly take for “high” spiritual enlightenment.
One probable reason why Japanese people living in America are taller than their counterparts in Japan is believed to be the consumption of cow’s milk and other meat and fish products, instead of plant foods high in phytates, which form the basis of the diet of their population in Japan and, as shown, provoke growth problems [20].
The harm of soy is explained by the presence of certain plant substances – phytates and toxins, which can theoretically be removed chemically.
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4 The main reason for the harm of soy – isoflavones. Scientific studies
Males 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, acquired a new type of feed for their birds – based on soy protein [47]. The result – their birds reached sexual maturity (acquired bright coloration) just a few months later! One of the producers of such feed commented on this fact as one of the advantages of the feed he produced.
In 1992, feeding such feed to an Australian parakeet, 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 hatch were deformed, stunted, and often died before reaching maturity, especially among female individuals. As a result, the overall population of birds in the aviary decreased.
Deformities of beaks and bones, dysbiosis, immune system disorders, pathologies, and aggressive behavior were observed in the birds. Autopsy revealed that their digestive organs were deteriorating.
But surprisingly, another aspect was that the list of problems was very similar to those observed in two children of the researchers who were fed on 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 is associated with various health disorders, including infertility, increased risk of cancer and leukemia among children, as well as the fact that soy genistein provokes thyroid dysfunction in animals [48].
Soy consumption is associated with infertility, increased risk of cancer and leukemia in children, and thyroid dysfunction
The doctor also examined the birds’ feed and found that it contained high levels of phytoestrogens, especially genistein. When feeding the birds with soy protein isolate was stopped, the flock gradually returned to normal levels.
The scientists clearly understood that it was necessary to warn the public and government officials about the toxins in soy products, especially about isoflavones (genistein), which adversely affect the endocrine system.
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 [49]. Other deviations in thyroid function were also observed, with many patients complaining of constipation, fatigue, and lethargy, even if their iodine intake was adequate.
In 1997, researchers from the National Toxicology Center of the USA made an unpleasant discovery that the cause of thyroid dysfunction is the same components of soy – isoflavones [50].
Important: And now the most interesting part: 25 grams of soy protein isolate per day (the minimum recommended amount by Protein Technology International to achieve cholesterol-lowering effects) contains between 50 to 70 mg of isoflavones.
For middle-aged women, a dose of just 45 mg of isoflavones is sufficient to cause thyroid dysfunction. Even after stopping soy consumption, the dysfunction persisted for three months [51].
100 grams of soy protein (the maximum recommended amount to achieve a cholesterol-lowering effect) can contain nearly 600 mg of isoflavones [52] – 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 [53].
100 grams of soy protein contain an equivalent of the female sex hormone estrogen equal to one hormonal pill
Laboratory studies have also shown that isoflavones inhibit the synthesis of steroid hormones [54], which are responsible for muscle growth.
Infertility, thyroid and liver diseases due to soy protein (isoflavones) have been observed by researchers in several animal species, including mice, cheetahs, quails, pigs, rats, sturgeons, and sheep [55].
Isoflavones are also credited with having a “beneficial effect” on postmenopausal symptoms in women, including mild hot flashes, protection against osteoporosis, and so on.
The degree of discomfort when raising temperature is subjective, and many studies confirm that women report a decrease in discomfort in proportion to the amount of soy protein consumed [56].
The claim that soy prevents osteoporosis is sensational, considering the fact that soy products block calcium and cause vitamin D deficiency.
If Asians indeed have lower rates of osteoporosis than residents of Western countries, it is only because their diet contains higher amounts of vitamin D from lard, shrimp, and other seafood, as well as greater amounts of calcium from broths made from bones.
The reason that Western residents 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.
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5 Soy and cancer
Today in America, official bodies have passed a resolution prohibiting any claims regarding the anti-cancer properties of products on packaging. However, it does not restrict soy producers and marketers from promoting such claims in literature and online.
One of the brochures states: “In addition to protecting against cardiovascular diseases, soy demonstrates powerful anti-cancer benefits… The Japanese, who eat 30 times more soy than North Americans, have a lower incidence of breast, uterine, and prostate cancer”[37].
And this is indeed the case. But the same Japanese and Asians in general have much higher rates of other types of cancer, particularly esophageal, stomach, pancreatic, and liver cancer [38].
Asians around the world also have high rates of thyroid cancer [39].
Based on these facts, it would be fair for those who speak about the anti-cancer effects of soy (referring to reproductive organ cancers) to also warn about its potential increased risk of thyroid and digestive organ cancers.
To further clarify the issue, let’s find out how much soy the same Asians actually consume.
In 1998, one study on the daily consumption of soy protein by Japanese individuals found: ~8 g for men, ~7 grams for women, i.e., less than two teaspoons [40]. In another study, it was established that legume consumption in China varies from 0 to 58 g per day, with an average of about 12 grams [41].
If we assume that two-thirds of legume consumption is soy, then the maximum consumption is about 40 grams (less than three tablespoons a day), and the average is 9 grams (less than two teaspoons).
A study conducted in 1930 showed that soy products accounted for only 1.5% of calories in the Chinese diet, while the majority of calories (65%) came from… pork [42] (Asians traditionally cook with lard, not vegetable oil!).
Traditionally fermented soy products are used as a tasty natural seasoning in Asian cuisine. In times of abundance, Asians consume soy products in small amounts, as seasonings rather than as substitutes for animal products.
There are only two exceptions: times of famine and monks living in monasteries. The latter take a vow of celibacy, lead a vegetarian lifestyle, and therefore soy is an ideal product for them, also reducing sexual desire.
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One example of scientific speculation on the benefits of soy in the fight against cancer is a meta-analysis (analysis of a large number of scientific studies) conducted by Mark Messina in 1994 [43].
The conclusion of this scientist is as follows: in 26 animal studies, 65% (far from 100%!) showed positive anti-cancer protective properties of soy.
However, the author somehow forgot to include at least one study in his work where soy feeding led to pancreatic cancer [44].
In the human studies considered by the author, the results were ambiguous: a small portion showed some protective effect, but most showed no connection at all between soy consumption and cancer incidence.
Mark Messina concluded that “the data from his research CANNOT be used as a basis for claiming that soy consumption reduces the risk of cancer.”
Nevertheless, in one of his books, Messina recommends consuming at least one cup or 230 grams of soy products per day as an “optimal diet for cancer prevention.”
Today, thousands of women consume soy in the hope that it will protect them from breast cancer.
In 1996, researchers found that women who regularly included soy protein isolate in their diet had an increased incidence of epithelial hyperplasia – a condition that precedes the development of a cancerous tumor [45].
A year later, scientists discovered that one type of soy isoflavone – genistein – stimulates breast cells to enter the reproduction cycle. This finding forced the authors of the study to conclude that to prevent breast cancer, women SHOULD NOT consume soy products [46].
The benefits of soy in combating cancer are questionable. Some studies, on the contrary, suggest that its consumption may stimulate tumor development.
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6 Harm of infant soy formulas
In the aforementioned study on the harmful effects of soy protein on the health of birds, as well as the children of the Jameses research family, it was the soy isoflavones that were the cause.
In 1998, scientists reported that the daily dose of isoflavones in soy-based infant formulas is 6-11 times higher than the amount that causes hormonal disruptions in adults consuming soy products.
The concentration of isoflavones in infants fed soy-based formulas was 13,000 to 22,000 times higher than the concentration of the female hormone in the blood of children fed cow’s milk formulas [57].
Important: In the USA, about 25% of infants on formula are fed soy-based formulas – this is a much higher percentage than in other parts of the Western world.
Scientists have calculated that a baby fed with soy formula receives a dose of the female sex hormone (estrogen) equivalent to at least five contraceptive pills a day (based on body weight) [58].
In contrast, phytoestrogens have not been found in infant formulas or in a mother’s breast milk, even when she consumed soy products.
A baby fed with soy formula receives a dose of the female sex hormone (estrogen) equivalent to five contraceptive pills a day (based on body weight)
It has long been known that soy infant formulas can cause thyroid problems in infants. But what effect do soy products have on the hormonal development of infants, both male and female?
In male infants, there is a “surge of testosterone” during the first few months of life, when its level can be as high as that of an adult male. During this period, the child is programmed to develop male characteristics; not only the sexual organs and other male physical traits but also certain patterns of male behavior in the brain.
In monkeys, for example, a deficiency of male hormones leads to impaired spatial perception development (which is normally better in men than in women), learning ability, and visual recognition (important for reading, for example) [59].
It is evident that under the influence of early hormonal environment distortion in the infant’s body, the formation of incorrect patterns of future sexual orientation is likely.
In one experiment, a male child who was “supplemented” during pregnancy with a synthetic analog of the female sex hormone (estrogen), which in animals produces the same effect as soy phytoestrogens, had smaller than normal testicles [60].
Learning disabilities, especially among male children, have reached epidemic proportions today. Feeding soy to infants, which began to gain popularity in the early 1970s, cannot be ignored as a likely cause.
And what about girls? Today, a frightening number of young females are reaching sexual maturity significantly earlier than usual, according to a recent study published in the journal Pediatrics [61].
Researchers found that 1% of all girls today show signs of puberty, such as breast development or pubic hair, at the age of three; by eight years old, 14.7% of white girls and 50% of African American girls at the age of 8 have clearly expressed one or both of these signs.
In research conducted in Puerto Rico, scientists concluded in 1986 that the most likely cause of early puberty in girls is not chicken meat consumed in food, but soy formulas for feeding infants [63].
The consequences of a “shortened” childhood are tragic. Young mature girls must struggle with strong feelings of sexual attraction, for which they are not psychologically prepared.
Early maturation often leads to reproductive system problems later in life, including menstrual disorders, infertility, and breast cancer.
Parents of children who were fed soy formulas also report other issues that manifest in their children. Among them are: unbalanced emotional behavior, asthma, immune system problems, pituitary insufficiency, thyroid diseases, and irritable bowel syndrome – the same endocrine and digestive disorders observed in parrots in the experiments described above.
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7 Soy Protein Isolate: Benefit? Harm? Or Deception?
Soy protein isolate is the result of manufacturers’ persistent efforts to remove all the harmful substances mentioned above. It is a key component of most soy products that mimic meat and dairy products, including infant formulas and some types of soy milk.
Despite manufacturers’ efforts, they have not succeeded in creating the perfect product: harmful substances are not completely removed from it, and moreover, new ones are added. See our material on the harm of soy protein isolate.
Phytates are not completely removed from soy protein isolate
Important: Most harmful substances that hinder protein digestion (inhibitors) and mineral absorption are removed during high-temperature processing, but not all.
Their content in the final product – soy protein isolate – can vary by 5 times among different manufacturers [21].
Protein in soy protein isolate is partially destroyed
There is also another “but” in the process of obtaining soy protein isolate. During high-temperature processing (drying), partial destruction (denaturation) of the protein occurs, which reduces its biological value and makes it less effective in building muscle mass [23].
For this reason, animals fed soy feed require additional supplements in the form of individual amino acids (particularly lysine) for normal growth.
Soy protein isolate contains carcinogens and toxins
And that’s not all. At the final stage of high-temperature processing, nitrites are formed, which are strong carcinogens.
The alkaline processing to remove fiber is accompanied by the formation of toxins in soy protein isolate (lysinoalanine) [24].
Soy protein isolate contains artificial flavor additives
To mask the strong characteristic taste of soybeans and add flavor, artificial flavor additives, particularly monosodium glutamate, are often added to soy protein isolate [25]. It is due to these flavor additives that the “cow” taste is obtained in soy milk.
Soy protein isolate, despite technological processing, still contains harmful substances that hinder protein digestion and mineral absorption; it also contains carcinogens and toxins formed during manufacturing, as well as artificial additives to enhance flavor and color
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