Is Soya Healthy?28/10/2016 2022-06-06 0:15
Is Soya Healthy?
Soy is still widely perceived to be a “health food” in the United States, raking in some $4 billion a year. In the United States, every part of the soybean is used for profit, including soy lecithin — the waste left over after a soybean is processed — and soy protein isolate, which was initially invented to be used to make cardboard.
Many people consume soy because of claims that it can reduce the risk of heart disease, alleviate symptoms of menopause, lower cholesterol and even cut your risk of cancer.
But in reality, as Mary Vance describes in the important essay linked below, when people consume soy products it can eventually lead to health problems ranging from digestive upset and bloating to hormonal disruption. And among infants, the estrogens in soy formula can be devastating, causing problems in their brains, reproductive systems and thyroid glands.
There are 100 years worth of studies demonstrating that soy products can be hazardous to your health, but soy is nonetheless now everywhere in our food supply, often hidden in processed foods.
The Israeli Health Ministry recently issued a health advisory strongly recommending that soy foods be eaten only in moderation. They also recommended that soy formula be avoided altogether by infants.
A Host of Disorders
There are hundreds of studies linking soy with such disorders as:
• Digestive problems
• Thyroid dysfunction
• ADD and ADHD
• Reproductive disorders
Phytoestrogens are the Culprit
The Israeli Ministry based its advice on the findings of a panel of nutritionists, oncologists, pediatricians and other specialists who spent over a year looking at the available evidence. They concluded that the phytoestrogens in soy (estrogen-like plant hormones) can be harmful. Their recommendations are in accord with those made by the United Kingdom’s chief medical officer and the British Dietetic Association.
The panel found that:
• The evidence that soy alleviates menopausal symptoms is inconsistent.
• Soy phytoestrogens increase the risk of breast cancer.
• Soy phytoestrogens can also reduce male fertility.
They also noted that while soy has been shown to reduce blood cholesterol, there is no proof that it reduces the risk of heart disease.
The panel concluded that the proven risks of soy foods outweigh the possible benefit.
The National Institutes of Health (NIH) has convened a scientific panel to review the safety of soy baby formula and genistein, a plant estrogen found in soy.
Genistein can mimic the effects of estrogen in humans, which has raised concerns about effects on human development and reproduction. The panel intends to look into these possible effects, such as the research that suggests soy consumption could affect the menstrual cycle.
Many people are still convinced that soy is a health food, but it is important to recognize that soy clearly has a downside.
Soybeans are high in natural toxins, also known as antinutrients
This includes a large quantity of inhibitors that deter the enzymes needed for protein digestion. Further, these enzyme inhibitors are not entirely disabled during ordinary cooking. The result is extensive gastric distress and chronic deficiencies in amino acid uptake, which can result in dangerous pancreatic impairments and cancer.
• Soybeans contain hemaglutins, which cause red blood cells to clump together. Soybeans also have growth-depressant substances, and while these substances are reduced in processing, they are not completely eliminated.
• Soy contains goitrogens, which can frequently lead to depressed thyroid function.
• Most soybeans are genetically modified, and they contain one of the highest levels of pesticide contamination of all foods.
• Soybeans are very high in phytates, which prevent the absorption of minerals including calcium, magnesium, iron and zinc, all of which are co-factors for optimal biochemistry in the body.
• Finally, in an effort to remove antinutrients from soy, out of the final product, soybeans are taken through a series of chemical processes including acid washing the soy in aluminum tanks. This leaches high levels of aluminum, a toxic heavy metal, into the final soy products. Many soy foods also have toxic levels of manganese. Soy formula has up to 80 times higher manganese than is found in human breast milk.
Fermented soy products like tempeh, natto and miso and soybean sprouts don’t have these problems and can actually be quite healthy. I recommend that you avoid all non-fermented soy such as tofu, soy protein products, soymilk and especially soy baby formula, which should never be used for infants, and only eat fermented soy if you choose to eat it.
What About the Studies?
In recent years, several studies have been made regarding the soybean νs effect on human health. The results of those studies, largely underwritten by various factions of the soy industry, were of course overwhelmingly in favor of soy. The primary claims about soy’s health benefits are based purely on bad science. Although primary arguments for cancer patients to use soy focus on statistics showing low rates of breast, colon and prostate cancer among Asian people, there are obvious facts being utterly ignored. While the studies boast that Asian women suffer far fewer cases of breast cancer than American women do, the hype neglects to point out that these Asian women eat a diet that is dramatically different than their American counterparts.
The standard Asian diet consists of more natural products, far less fatty meat, greater amounts of vegetables and more fish. Their diets are also lower in chemicals and toxins, as they eat far fewer processed (canned, jarred, pickled, frozen) foods. It is likely these studies are influenced by the fact that cancer rates rise among Asian people who move to the U.S. and adopt American-ized diets. Of course, this change of diet goes hand-in-hand with a dramatic shift in lifestyle. Ignoring the remarkable diet and lifestyle changes, to assume only that reduced levels of soy in these Americanized Asian diets is a primary factor in greater cancer rates is poor judgment, and as stated above, bad science. The changes of diet and lifestyle must be considered to reach the correct conclusion.
A widely circulated article, written by Jane E. Allen, AP Science Writer, titled, “Scientists Suggest More Soy in Diet”, cites in the course of a symposium, numerous speakers discussing the probable advantages of soy under the title, “Health Impact of Soy Protein.” However, the article states that the $50,000 symposium “was underwritten by Protein Technologies International of St. Louis, a DuPont subsidiary that makes soy protein!” In the course of the same symposium, Thomas Clarkson, professor of comparative medicine at Wake Forest University, states “Current hormone replacement therapy has been a dismal failure from a public health point of view,” not because PremarinΖ is known to cause uterine or other female organ cancers, but “because only 20 percent of the women who could benefit from it are taking it.”
Other popular arguments in support of soy state that fermented products, like tempeh or natto, contain high levels of vitamin B-12. However, these supportive arguments fail to mention that soy’s B-12 is an inactive B-12 analog, not utilized as a vitamin in the human body. Some researchers speculate this analog may actually serve to block the body’s B-12 absorption. It has also been found that allergic reactions to soybeans are far more common than to all other legumes. Even the American Academy of Pediatrics admits that early exposure to soy through commercial infant formulas, may be a leading cause of soy allergies among older children and adults.
In his classic book, A Cancer Therapy – Results of 50 Cases (p. 237), Dr. Gerson put “Soy and Soy Products” on the “FORBIDDEN” list of foods for Gerson Therapy patients. At the time, his greatest concerns were two items: the high oil content of soy and soy products, and the rather high rate of allergic reactions to soy. Soybeans can add as much as 9 grams of fat per serving, typically adding an average of 5 grams of fat per serving when part of an average American diet.
FDA Health Claim Challenged
On October 25, 1999 the US Food and Drug Administration (FDA) decided to allow a health claim for products “low in saturated fat and cholesterol” that contain 6.25 grams of soy protein per serving. Breakfast cereals, baked goods, convenience food, smoothie mixes and meat substitutes could now be sold with labels touting benefits to cardiovascular health, as long as these products contained one heaping teaspoon of soy protein per 100-gram serving.
The best marketing strategy for a product that is inherently unhealthy is, of course, a health claim.
“The road to FDA approval,” writes a soy apologist, “was long and demanding, consisting of a detailed review of human clinical data collected from more than 40 scientific studies conducted over the last 20 years. Soy protein was found to be one of the rare foods that had sufficient scientific evidence not only to qualify for an FDA health claim proposal but to ultimately pass the rigorous approval process.”
The “long and demanding” road to FDA approval actually took a few unexpected turns. The original petition, submitted by Protein Technology International, requested a health claim for isoflavones, the estrogen-like compounds found plentifully in soybeans, based on assertions that “only soy protein that has been processed in a manner in which isoflavones are retained will result in cholesterol lowering”.
In 1998, the FDA made the unprecedented move of rewriting PTI’s petition, removing any reference to the phyto-estrogens and substituting a claim for soy protein – a move that was in direct contradiction to the agency’s regulations. The FDA is authorized to make rulings only on substances presented by petition.
The abrupt change in direction was no doubt due to the fact that a number of researchers, including scientists employed by the US Government, submitted documents indicating that isoflavones are toxic.
The FDA had also received, early in 1998, the final British Government report on phytoestrogens, which failed to find much evidence of benefit and warned against potential adverse effects.
Even with the change to soy protein isolate, FDA bureaucrats engaged in the “rigorous approval process” were forced to deal nimbly with concerns about mineral blocking effects, enzyme inhibitors, goitrogenicity, endocrine disruption, reproductive problems and increased allergic reactions from consumption of soy products.
One of the strongest letters of protest came from Dr Dan Sheehan and Dr Daniel Doerge, government researchers at the National Center for Toxicological Research. Their pleas for warning labels were dismissed as unwarranted.
“Sufficient scientific evidence” of soy’s cholesterol-lowering properties is drawn largely from a 1995 meta-analysis by Dr James Anderson, sponsored by Protein Technologies International and published in the New England Journal of Medicine.
A meta-analysis is a review and summary of the results of many clinical studies on the same subject. Use of meta-analyses to draw general conclusions has come under sharp criticism by members of the scientific community.
“Researchers substituting meta-analysis for more rigorous trials risk making faulty assumptions and indulging in creative accounting,” says Sir John Scott, President of the Royal Society of New Zealand. “Like is not being lumped with like. Little lumps and big lumps of data are being gathered together by various groups.”
There is the added temptation for researchers, particularly researchers funded by a company like Protein Technologies International, to leave out studies that would prevent the desired conclusions. Dr Anderson discarded eight studies for various reasons, leaving a remainder of twenty-nine.
The published report suggested that individuals with cholesterol levels over 250 mg/dl would experience a “significant” reduction of 7 to 20 per cent in levels of serum cholesterol if they substituted soy protein for animal protein. Cholesterol reduction was insignificant for individuals whose cholesterol was lower than 250 mg/dl.
In other words, for most of us, giving up steak and eating vegieburgers instead will not bring down blood cholesterol levels. The health claim that the FDA approved “after detailed review of human clinical data” fails to inform the consumer about these important details.
Research that ties soy to positive effects on cholesterol levels is “incredibly immature”, said Ronald M. Krauss, MD, head of the Molecular Medical Research Program and Lawrence Berkeley National Laboratory. He might have added that studies in which cholesterol levels were lowered through either diet or drugs have consistently resulted in a greater number of deaths in the treatment groups than in controls – deaths from stroke, cancer, intestinal disorders, accident and suicide.
Cholesterol-lowering measures in the US have fuelled a $60 billion per year cholesterol-lowering industry, but have not saved us from the ravages of heart disease.
Soy And Cancer
The new FDA ruling does not allow any claims about cancer prevention on food packages, but that has not restrained the industry and its marketers from making them in their promotional literature.
“In addition to protecting the heart,” says a vitamin company brochure, “soy has demonstrated powerful anticancer benefits…the Japanese, who eat 30 times as much soy as North Americans, have a lower incidence of cancers of the breast, uterus and prostate.”
Indeed they do. But the Japanese, and Asians in general, have much higher rates of other types of cancer, particularly cancer of the esophagus, stomach, pancreas and liver. Asians throughout the world also have high rates of thyroid cancer. The logic that links low rates of reproductive cancers to soy consumption requires attribution of high rates of thyroid and digestive cancers to the same foods, particularly as soy causes these types of cancers in laboratory rats.
Just how much soy do Asians eat? A 1998 survey found that the average daily amount of soy protein consumed in Japan was about eight grams for men and seven for women – less than two teaspoons. The famous Cornell China Study, conducted by Colin T. Campbell, found that legume consumption in China varied from 0 to 58 grams per day, with a mean of about twelve.
Assuming that two-thirds of legume consumption is soy, then the maximum consumption is about 40 grams, or less than three tablespoons per day, with an average consumption of about nine grams, or less than two teaspoons. A survey conducted in the 1930s found that soy foods accounted for only 1.5 per cent of calories in the Chinese diet, compared with 65 per cent of calories from pork. (Asians traditionally cooked with lard, not vegetable oil!)
Traditionally fermented soy products make a delicious, natural seasoning that may supply important nutritional factors in the Asian diet. But except in times of famine, Asians consume soy products only in small amounts, as condiments, and not as a replacement for animal foods – with one exception. Celibate monks living in monasteries and leading a vegetarian lifestyle find soy foods quite helpful because they dampen libido.
It was a 1994 meta-analysis by Mark Messina, published in Nutrition and Cancer, that fuelled speculation on soy’s anticarcinogenic properties.43 Messina noted that in 26 animal studies, 65 per cent reported protective effects from soy. He conveniently neglected to include at least one study in which soy feeding caused pancreatic cancer – the 1985 study by Rackis. In the human studies he listed, the results were mixed.
A few showed some protective effect, but most showed no correlation at all between soy consumption and cancer rates. He concluded that “the data in this review cannot be used as a basis for claiming that soy intake decreases cancer risk”. Yet in his subsequent book, The Simple Soybean and Your Health, Messina makes just such a claim, recommending one cup or 230 grams of soy products per day in his “optimal” diet as a way to prevent cancer.
Thousands of women are now consuming soy in the belief that it protects them against breast cancer. Yet, in 1996, researchers found that women consuming soy protein isolate had an increased incidence of epithelial hyperplasia, a condition that presages malignancies. A year later, dietary genistein was found to stimulate breast cells to enter the cell cycle – a discovery that led the study authors to conclude that women should not consume soy products to prevent breast cancer.
Birth Control Pills For Babies
But it was the isoflavones in infant formula that gave the Jameses the most cause for concern. In 1998, investigators reported that the daily exposure of infants to isoflavones in soy infant formula is 6 to11 times higher on a body-weight basis than the dose that has hormonal effects in adults consuming soy foods. Circulating concentrations of isoflavones in infants fed soy-based formula were 13,000 to 22,000 times higher than plasma estradiol concentrations in infants on cow’s milk formula.
Approximately 25 per cent of bottle-fed children in the US receive soy-based formula – a much higher percentage than in other parts of the Western world. Fitzpatrick estimated that an infant exclusively fed soy formula receives the estrogenic equivalent (based on body weight) of at least five birth control pills per day. By contrast, almost no phytoestrogens have been detected in dairy-based infant formula or in human milk, even when the mother consumes soy products.
Scientists have known for years that soy-based formula can cause thyroid problems in babies. But what are the effects of soy products on the hormonal development of the infant, both male and female?
Male infants undergo a “testosterone surge” during the first few months of life, when testosterone levels may be as high as those of an adult male. During this period, the infant is programmed to express male characteristics after puberty, not only in the development of his sexual organs and other masculine physical traits, but also in setting patterns in the brain characteristic of male behavior.
In monkeys, deficiency of male hormones impairs the development of spatial perception (which, in humans, is normally more acute in men than in women), of learning ability and of visual discrimination tasks (such as would be required for reading). It goes without saying that future patterns of sexual orientation may also be influenced by the early hormonal environment.
Male children exposed during gestation to diethylstilbestrol (DES), a synthetic estrogen that has effects on animals similar to those of phytoestrogens from soy, had testes smaller than normal on maturation.
Learning disabilities, especially in male children, have reached epidemic proportions. Soy infant feeding – which began in earnest in the early 1970s – cannot be ignored as a probable cause for these tragic developments.
As for girls, an alarming number are entering puberty much earlier than normal, according to a recent study reported in the journal Pediatrics. Investigators found that one per cent of all girls now show signs of puberty, such as breast development or pubic hair, before the age of three; by age eight, 14.7 per cent of white girls and almost 50 per cent of African-American girls have one or both of these characteristics.
New data indicate that environmental estrogens such as PCBs and DDE (a breakdown product of DDT) may cause early sexual development in girls.62 In the 1986 Puerto Rico Premature Thelarche study, the most significant dietary association with premature sexual development was not chicken – as reported in the press – but soy infant formula.
The consequences of this truncated childhood are tragic. Young girls with mature bodies must cope with feelings and urges that most children are not well-equipped to handle. And early maturation in girls is frequently a harbinger for problems with the reproductive system later in life, including failure to menstruate, infertility and breast cancer.
Parents who have contacted the Jameses recount other problems associated with children of both sexes who were fed soy-based formula, including extreme emotional behavior, asthma, immune system problems, pituitary insufficiency, thyroid disorders and irritable bowel syndrome – the same endocrine and digestive havoc that afflicted the Jameses’ parrots.
Dissension In The Ranks
Organizers of the Third International Soy Symposium would be hard-pressed to call the conference an unqualified success. On the second day of the symposium, the London-based Food Commission and the Weston A. Price Foundation of Washington, DC, held a joint press conference, in the same hotel as the symposium, to present concerns about soy infant formula.
Industry representatives sat stony-faced through the recitation of potential dangers and a plea from concerned scientists and parents to pull soy-based infant formula from the market. Under pressure from the Jameses, the New Zealand Government had issued a health warning about soy infant formula in 1998; it was time for the American government to do the same.
On the last day of the symposium, presentations on new findings related to toxicity sent a well-oxygenated chill through the giddy helium hype. Dr Lon White reported on a study of Japanese Americans living in Hawaii, that showed a significant statistical relationship between two or more servings of tofu a week and “accelerated brain aging”.
Those participants who consumed tofu in mid-life had lower cognitive function in late life and a greater incidence of Alzheimer’s disease and dementia. “What’s more,” said Dr White, “those who ate a lot of tofu, by the time they were 75 or 80 looked five years older”. White and his colleagues blamed the negative effects on isoflavones – a finding that supports an earlier study in which postmenopausal women with higher levels of circulating estrogen experienced greater cognitive decline.
Scientists Daniel Sheehan and Daniel Doerge, from the National Center for Toxicological Research, ruined PTI’s day by presenting findings from rat feeding studies, indicating that genistein in soy foods causes irreversible damage to enzymes that synthesise thyroid hormones.
“The association between soybean consumption and goiter in animals and humans has a long history,” wrote Dr Doerge. “Current evidence for the beneficial effects of soy requires a full understanding of potential adverse effects as well.”
Dr Claude Hughes reported that rats born to mothers that were fed genistein had decreased birth weights compared to controls, and onset of puberty occurred earlier in male offspring. His research suggested that the effects observed in rats “…will be at least somewhat predictive of what occurs in humans.
There is no reason to assume that there will be gross malformations of fetuses but there may be subtle changes, such as neurobehavioral attributes, immune function and sex hormone levels.” The results, he said, “could be nothing or could be something of great concern…if mom is eating something that can act like sex hormones, it is logical to wonder if that could change the baby’s development”.
A study of babies born to vegetarian mothers, published in January 2000, indicated just what those changes in baby’s development might be. Mothers who ate a vegetarian diet during pregnancy had a fivefold greater risk of delivering a boy with hypospadias, a birth defect of the penis. The authors of the study suggested that the cause was greater exposure to phytoestrogens in soy foods popular with vegetarians.
Problems with female offspring of vegetarian mothers are more likely to show up later in life. While soy’s estrogenic effect is less than that of diethylstilbestrol (DES), the dose is likely to be higher because it’s consumed as a food, not taken as a drug. Daughters of women who took DES during pregnancy suffered from infertility and cancer when they reached their twenties.
Question Marks Over GRAS Status
Lurking in the background of industry hype for soy is the nagging question of whether it’s even legal to add soy protein isolate to food. All food additives not in common use prior to 1958, including casein protein from milk, must have GRAS (Generally Recognized As Safe) status. In 1972, the Nixon administration directed a re-examination of substances believed to be GRAS, in the light of any scientific information then available.
This re-examination included casein protein that became codified as GRAS in 1978. In 1974, the FDA obtained a literature review of soy protein because, as soy protein had not been used in food until 1959 and was not even in common use in the early 1970s, it was not eligible to have its GRAS status grandfathered under the provisions of the Food, Drug and Cosmetic Act.
The scientific literature up to 1974 recognized many antinutrients in factory-made soy protein, including trypsin inhibitors, phytic acid and genistein. But the FDA literature review dismissed discussion of adverse impacts, with the statement that it was important for “adequate processing” to remove them.
Genistein could be removed with an alcohol wash, but it was an expensive procedure that processors avoided. Later studies determined that trypsin inhibitor content could be removed only with long periods of heat and pressure, but the FDA has imposed no requirements for manufacturers to do so.
The FDA was more concerned with toxins formed during processing, specifically nitrites and lysinoalanine. Even at low levels of consumption – averaging one-third of a gram per day at the time – the presence of these carcinogens was considered too great a threat to public health to allow GRAS status.
Soy protein did have approval for use as a binder in cardboard boxes, and this approval was allowed to continue, as researchers considered that migration of nitrites from the box into the food contents would be too small to constitute a cancer risk. FDA officials called for safety specifications and monitoring procedures before granting of GRAS status for food.
These were never performed. To this day, use of soy protein is codified as GRAS only for this limited industrial use as a cardboard binder. This means that soy protein must be subject to premarket approval procedures each time manufacturers intend to use it as a food or add it to a food.
Soy protein was introduced into infant formula in the early 1960s. It was a new product with no history of any use at all. As soy protein did not have GRAS status, premarket approval was required. This was not and still has not been granted. The key ingredient of soy infant formula is not recognized as safe.