I've never made a secret of the fact that I'm not a big fan of the benefits of soy, at least when used as a primary protein source. Soy products are by no means as safe or nutritious as their proponents would have us believe. Then again, on the other side of the equation, the dangers of soy are nowhere near as pronounced as many of its detractors claim. On a good-bad scale, they probably come in at a 35:65 ratio, with the 65 lined up on the negative side. However, a great deal depends on which soy products you use and what your age is.
The History of Soy
The proponents of the benefits of soy state that the value and safety of soy products have been proven over several millennia of use in East Asia. Unfortunately, that's only half true. Yes, soy has been grown in Asia for several millennia, but not as a food. In fact, it was originally used only in crop rotation to fix nitrogen. For a long, long time, soy was not considered suitable for eating, at least until fermented products such as soy sauce, tempeh, natto, and miso came along. In America, until the 1920's, soy was grown only for its industrial by-products. Then as an animal feed -- still its primary use -- and only more recently has it been used as a primary protein source. In Japan, the average consumption of soy runs about 8-9 grams of soy products a day. That's less than two teaspoons. Again, most of that's fermented (miso, soy sauce, and natto) or precipitated (tofu).1 China and Hong Kong, however, have moved away from their roots and are now consuming large amounts of soy beverages -- more than in Europe and the US in fact. Soy protein isolate is more of a Western phenomenon, at least to this point in time, although countries like India are exploring its possibilities as a supplemental protein source for its large, less economically advantaged, vegetarian populace.2
Pretty much all of the data supporting the benefits of soy as a food comes as the result of recent studies promoted by the agricultural industry to justify soy's newfound status as a "healthy alternative" to dairy and meat. It should be taken with a grain of salt -- and I'm not referring to seasoning.
The Benefits of Soy
Current marketing says that soy is rich in protein and other important nutrients and that it makes a valuable contribution to an overall healthy diet. The curious thing is that this marketing comes from both big agribusiness and the health food industry -- strange bedfellows indeed. Nevertheless, there are some studies on the benefits of soy to support their enthusiasm. Soy is high in phytoestrogens -- particularly isoflavones -- which means that it is likely to have a positive hormonal impact on both men and women. And in fact, some studies have shown that consuming soy products can help with menopausal symptoms in women3 and prostate problems in men.4,5 Studies on the benefits of soy in regard to menopausal bone health and the prevention of breast cancer, though, have been more equivocal despite claims to the contrary.
Perhaps unsurprisingly, given that they are (unless adulterated) low in saturated fats and have no cholesterol, the consumption of soy products has been associated with improved cardiovascular health. Specifically, it has been found that diets high in soy products are associated with lower blood pressure,6 reduced triglyceride and cholesterol levels,7 and a reduced incidence of diabetes.8
All of that said, a 2011 report from the North American Menopause Society was far more equivocal in its support of the benefits of soy. According to the report, "From the hundreds of studies reviewed in this report, there are mixed results of the effects on midlife women. Soy-based isoflavones are modestly effective in relieving menopausal symptoms; supplements providing higher proportions of genistein or increased in S(-)-equol may provide more benefits. Soy food consumption is associated with lower risk of breast and endometrial cancer in observational studies. The efficacy of isoflavones on bone has not been proven, and the clinical picture of whether soy has cardiovascular benefits is still evolving. Preliminary findings on cognitive benefit from isoflavone therapy support a "critical window" hypothesis wherein younger postmenopausal women derive more than older women."9 Specifically, the report found that:
- Soy relieved certain menopausal symptoms. "If you give estrogen a 9 out of 10 score, and placebo 4 of 10, soy would be about 6.5."
- "On bone health, we really didn't find adequate evidence to recommend its use for preventing or reducing the risk of osteoporosis and osteoporotic fracture."
- Soy's heart health benefit is still evolving in research.
- Soy appears to help women under age 65 with cognitive function, but not those over 65.
Soy as a Protein Source
At one time, soy protein was a waste product -- a byproduct from manufacturing soy oil. Then, in typical American industry brilliance (think fluoride), manufacturers found a way to turn a waste product that cost money to dispose of into a major money maker: they used it as cattle feed.10 And in fact, the use of soy protein as cattle feed is one of the primary driving forces in the growth of the meat and dairy industry. (It's also a major component of feed used to raise chickens, turkeys, pigs, cows, and even fish raised on fish farms.) The next step, obviously, was to make it palatable for human beings. In its raw form, after oil extraction, it looks and smells quite nasty. But by adding flavorings, preservatives, sweeteners, emulsifiers and synthetic nutrients, what was formerly cattle feed is turned into a pretty palatable meat substitute for humans.
Incidentally, soy milk used as a low-fat high-protein dairy substitute has seen the biggest gains in market share. Sales have increased exponentially from $2 million a year in 1980 to approximately $1billion a year today -- and that's just in the US.11
If you consider everywhere it's used (not just by bodybuilders, where whey is king), soy just might be the number one protein supplement on the planet. In fact, according to Margaret E. Cook-Newell, one of the lead researchers in a 1995 review of soy protein published in the New England Journal of Medicine,12 "There are 12,000 soy products on the market, and many more will be coming soon." Seven years later, that number is likely now much, much higher. The bottom line is that, worldwide, the soy protein market currently tops $5.1 billion a year and is projected to just keep on growing as the need for inexpensive protein supplementation only increases as it keeps pace with the world's expanding population and as incomes in third world countries continue to increase.13
The Dangers of Soy
As I mentioned earlier, soy was not used as a food in Asia until fermented soy products appeared. The reason is that soy contains some very powerful nutrient blockers -- bio-chemicals that stop your body from absorbing nutrients found in the soy…or in any other foods that you eat with the soy. There's nothing evil or sinister or even unusual about this. A number of foods contain similar "anti-nutrients." The reasons, at least from the plant's perspective, are simple: first, the plant doesn't want a seed or bean to "activate" until it is in a location suitable for growing; and second, anti-nutrients make plants unappealing to birds and insects. Thus, soy contains enzyme inhibitors and nutrient binders to prevent just that from happening. For most plants, exposure to water is all that is needed to nullify the anti-nutrients. That's why sprouting releases so many nutrients in seeds, and it's why we have to soak most beans overnight before cooking them -- to eliminate the "anti-nutrients." Key anti-nutrients include:
- Phytates are prevalent in cereal grains and are capable of forming insoluble complexes with calcium, zinc, iron, and other nutrients, thus interfering with their absorption by the body. The soybean has one of the highest phytate levels of any grain or legume, and unlike the phytates in most beans, the phytates in soy are highly resistant to soaking and long, slow cooking. Soy phytate levels, however, can be significantly reduced through a long period of fermentation. Soy milk is very high in phytates, whereas tofu, because of the precipitation process used in its manufacture, falls somewhere in between. People who consume large amounts of soy milk and tofu as their primary protein sources risk severe mineral deficiencies. The results of calcium, magnesium, iron, and zinc deficiency are well known. Diets high in phytic acid can be sufficient by themselves to cause rickets.14
- Trypsin inhibitors are proteins found in some raw plant foods (e.g. soybeans) that can inhibit digestion. There are four natural sources of trypsin inhibitors: bovine pancreas, ovomucoid, soybean, and lima bean. Trypsin inhibitors provide unique processes depending on their source. For example, inhibitors in the seeds of legumes (soybean and lima bean) act as a feeding deterrent for insects by disrupting proteases in the small intestine. Big agribusiness is trying to expand on this natural function by using it to develop insect resistant transgenic plants. (Of course, that makes the soy even less useful as a food, but at least crop will be bumper.) Soybean inhibitors have also been found to contribute to pancreatic hypertrophy in rats, again providing a deterrent to rats thinking of feeding on the soy.15
- Hemagglutinin is a complex protein that causes other proteins and cells to agglutinate, or clump together. Antibodies and lectins are hemagglutinins that you're probably familiar with. Viruses also make use of hemagglutinins to bind to host cells. Plants such as soy make use of phytohemagglutinins (plant based hemagglutinins) to defend against pests as they cause key cells in the pests, such as blood cells, to clump together. Levels of phytohemagglutinins are high in soy.16 Again, as with the other anti-nutrients, hemagglutinin is deactivated during fermentation.
Dangers of Soy Protein Isolate and Anti-Nutrients
The process of making soy protein isolates involves acid washes, alkaline baths, and high temperatures and, in fact, gets rid of many but not all of the anti-nutrients. Unfortunately, high temperature processing damages the protein -- it denatures it in a way that makes it harder to break down in the intestinal tract and, ultimately, harder to digest. Understand, certain kinds of denaturing, as provided by stomach acid, unfolds proteins in a way necessary for digestion. Heat, on the other hand, unfolds them in a way that resists digestion.
The bottom line is that even the FDA, in their opinion supporting the use of soy protein isolate, has acknowledged that it must be fortified with extra methionine, lysine, vitamins, and minerals -- either by addition to the soy isolate product, or as provided by other components of the diet.17
I've certainly been a proponent of phytoestrogens over the years as a defense against the petroleum based xenoestrogens that can lead to estrogen dominance. And that hasn't changed. Estrogen dominance can be a factor in all kinds of problems, including:
- Excess estrogen is the only known cause of endometrial cancer.
- Increased risk of breast cancer.
- Loss of bone mass.
- Increased risk of autoimmune disorders such as lupus.
- Fibrocystic breasts.
- Fibroid tumors.
- Depression and irritability.
- PMS symptoms such as cramping and bloating -- in addition to depression and irritability.
- Menopausal symptoms such as hot flashes and night sweats -- again, in addition to depression and irritability.
- Decreased sex drive.
- Increased body hair and thinning of scalp hair.
- Migraine headaches.
- Impaired thyroid function, including Grave's disease.
- Increased body fat.
- Increased blood clotting.
- Impaired blood sugar control.
- The astounding acceleration of puberty in young girls from an average age of 14 to 15, to now as young as 9 or 10. (This represents a speed up of as much as 1/3 sooner in their lives and has frightening implications for long term health.)
- And, finally, xenoestrogens have been strongly implicated in declining male sperm production and the increase in the rates of testicular cancer and prostate cancer.
Phytoestrogens work primarily by filling the body's estrogen receptor sites with weaker plant based estrogens so that those sites are no longer available to far stronger natural, synthetic, or even petroleum based estrogens. But…. as I have also said many times before. "Too much of a good thing is bad. Too much of any food or supplement is bad. If you over indulge in something, no matter how beneficial it is, it will result in illness, not health." Sun exposure, for example, is important for vitamin D production; but too much sun leads to dried out skin and a higher risk of skin cancer. Pure water is important. But if you overindulge, it can lead to "water intoxication" and even death. And fiber is crucial for intestinal health, but consume too much and it can lead to malabsorption of vitamins and minerals and, in some cases, even intestinal blockage. And the same rule applies to phytoestrogens. So how does that relate to soy?
Soy is packed with isoflavones. In fact, many of the benefits of soy consumption are attributed to its high isoflavone content. Isoflavones are polyphenolic compounds that are capable of exerting estrogen-like effects and are thus classified as phytoestrogens (plant-based compounds with estrogenic activity). Soy contains the highest concentration of phytoestrogens of any regularly consumed dietary source known. Specifically, there are three soy isoflavone glycosides: genistin, daidzin, and glycitin. And there are three soy isoflavone aglycones: genistein, daidzein, and glycitein. Studies have shown that these phytoestrogens are likely to be health promoting when taken in reasonable amounts. When taken at very high levels, though, the data is more conflicted. And keep in mind that in the case of children or infants on formula, it doesn't take much soy to pack the body with phytoestrogens on a per pound basis of bodyweight. And that's why studies on children are even more equivocal than those on adults. Some of the concerns associated with high soy intake for adults and children are:
- Male infertility.18 In studies, male subjects who have the highest soy intake also have the lowest sperm counts compared to men who eat no soy foods.19 In another study, after four weeks of using soy protein powder, the average testosterone levels of adult subjects decreased by 19%.20
- Abnormal bleeding of the uterus, endometriosis and polyps in women.21
- Thyroid problems.22 Consumption of as little as two tablespoons of soybeans per day for only one month results in a significant increase in thyroid-stimulating hormone.
- Goiter (or goitre).23 Goiters can come and go with the consumption and subsequent stoppage of soy milk.
- Brain atrophy.24 Poor cognitive test performance, enlargement of ventricles, and low brain weight were each significantly and independently associated with higher midlife tofu consumption. And short term, drinking less than one ounce of soy milk daily may lead to loss of memory.
- Kidney Stones. Soy contains oxalates, which cannot be metabolized by the body and are excreted through urine. Oxalates bind to calcium in the kidneys, which can lead to the formation of kidney stones, especially if you have a history of kidney stones.
And any problems with soy, as we've already indicated, are going to be amplified in infants and toddlers for the simple reason that they have lower body weight. The daily exposure of infants to isoflavones in soy formula is six to11 times higher on a body-weight basis than the dose that has hormonal effects in adults consuming soy foods. Total isoflavone concentrations of soy-based formulas prepared for infant feeding range from 32 to 47 thousandths of a gram per liter, whereas isoflavone concentrations in human breast milk are only 5.6 ± 4.4 millionths of a gram per liter.25 This translates as Isoflavone concentrations that are 13,000--22,000-fold higher than plasma estradiol concentrations in breastfed babies in early life. Or another way to look at it is that infants raised on soy formula receive the estrogen equivalent (based on body weight) of some five birth control pills per day. That is an astounding difference!
And it means that all of the effects we've already talked about in adults occur in infants and children, but at an accelerated rate. For example:
- Thyroid problems.27
- Sexual anarchy. Testosterone levels in infants as high as found in adult males.28 Baby girls showing signs of puberty as early as age three.29
- Uterine fibroids. Side effects and long-term health consequences to infants fed soy milk formula containing isoflavones were reported in Environmental Health Perspectives in March 2010. From 50,000 participants involved in a four-year study, findings were that women who were fed soy milk in infancy had a 25 percent higher incidence of uterine fibroids by age 35.30
Dangers of Soy Allergens
Another factor to consider when looking at soy protein is that there is actually no such thing as "soy protein" or any other "type" of protein, for that matter. Each source of protein is actually a conglomeration of several protein fractions that we lump together under their source name. Dairy protein, for example, actually describes a group of proteins that includes casein (which itself is a conglomeration of alpha caseins 1&2, beta casein, and kappa casein), alpha-lactalbumin, beta-lactoglobulin, and bovine serum albumin. Soy protein, likewise, is a mix of a number of protein fractions, although the names for the soy fractions are more utilitarian than for dairy, more prosaic if you will. Soy protein fractions include: 28 kD, 30-34 kD, 37 kD, 49 kD, and 50 kD. It's not necessary to know the names of all the different protein fractions in the different types of protein, but it is vital to know that they exist. Why? Because the different fractions have different degrees of digestibility and promote different degrees of allergic response. The prime culprit in soy, for example, is most likely 30-kD allergen (Gly m Bd 30).31 Ultimately, the quality of a protein source (and its tendency to cause allergic response) is determined by how your body handles each and every fraction in that source. With at least 16 allergenic proteins (with some estimates as high as 25 to 30), soy ranks as one of the most allergenic proteins in existence.
Mildly allergic people may have itching and a few hives, while those who are severely allergic may experience severe, life-threatening symptoms such as breathing problems or swelling of the throat. But most people fall below those two levels of response -- into the "almost" unnoticeable level. At this level, symptoms, which may include gas, bloating, and low level irritation of intestinal tissue, are often not even identified at a conscious level and are almost never connected to the soy that causes them. The problem with low level allergic responses does not stem from taking soy occasionally, but if it is used as a regular component of the diet. Then these low level "unconscious" conditions can become chronic illness -- that magically "seems" to appear out of nowhere and for no particular reason.
Soy in the U.S. is Almost All Genetically Modified
The first applications for the development of genetically engineered soy did not even appear until 1987. By the year 2000, over 50% of all soybeans planted in the U.S. were, according to current terminology, genetically modified organisms (GMO). By 2007, that number had soared to an astounding 91%. It's important to understand that soybeans have not been modified to improve their nutritional value, but rather to improve crop yields. In fact, one of the primary genetic modifications is to make soybeans "Roundup Ready." Roundup is an herbicide that kills weeds. "Roundup Ready" means that the soy has been genetically modified so that it is unaffected by the herbicide. This allows farmers to spray Roundup to their heart's content to kill weeds, thus increasing farming efficiency. Unfortunately, this means that your soy comes packed with Roundup…and its genetic modification.
And as Dr. Joseph Mercola points out, not only is GM soy linked to an increase in allergies, but "the only published human feeding study on GM foods ever conducted verified that the gene inserted into GM soy transfers into the DNA of our gut bacteria and continues to function. This means that years after you stop eating GM soy, you may still have a potentially allergenic protein continuously being produced in your intestines.32" In other words, if you eat GMO soy, there is a high likelihood that you will be genetically modified too.
The problem is that the benefits of soy are not miraculous. Yes, if you eat small amounts of organic, fermented versions, it actually provides some substantial health benefits. But if consumed as a primary protein source in unfermented forms -- such as soy milk and tofu -- its health and safety values are much more suspect. The dangers of soy are not overwhelming, but they cannot be ignored. I know there are soy fanatics out there -- even many who read my newsletters -- but if it were me (and it is):
- I would not consume more than one ounce of soy a day -- if at all.
- I would eat only the fermented forms -- tempeh, natto, miso, and "real" soya sauce.
- I would absolutely not use soy milk because it is too easy to consume too much soy that way. Personally, I now use almond milk. It's low carb, low fat, and low calorie. On the downside it's also low protein, and if you have a nut allergy, it's undoable. Other options are coconut milk and rice milk -- but I would use those in lesser amounts because of their respective fat content and carb contents. And if you opt for dairy, make sure it's organic, raw, and grass fed --if you can get it.
- I would eat only organic soy. I would not touch the GMO version -- although that's getting harder and harder to avoid as many organic soy crops are becoming contaminated as GMO pollen spreads.33
- I would not use soy isolate as a protein supplement. As I have said previously, my preference is for a rice/pea protein blend, although 70% hemp protein is emerging as an interesting alternative. I would even use organic, grass fed, cold processed whey before I opted for soy. (Note: although I like rice/pea protein for adults, I would not recommend it for children.)
Again, if you choose to partake of the benefits of soy, restrict your consumption to small amounts and eat only organically grown fermented products. At least that will provide you a hedge against unignorable soy dangers.
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- 20. Arbor 2009.
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- 32. Joseph Mercola. "This "Miracle Health Food" Has Been Linked to Brain Damage and Breast Cancer." Mercola.com 18 Sept 2010. (Accessed 10 Sept 2012.) http://articles.mercola.com/sites/articles/archive/2010/09/18/soy-can-damage-your-health.aspx
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