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Think Soy is Healthy? Here’s Why it’s Not as Good as You Think

April 21, 2004 | 44,908 views
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By Dr. Joseph Mercola

Soy has gained the reputation as a health food, in large part, because of the numerous health claims surrounding its products. Interestingly, a friend of mine forwarded a pro-soy article to me to refute and I was surprised to find my name mentioned in it as "an ardent advocate of eating beef, chicken, turkey, ostrich, and other meats."

The article is What About Soy? by John Robbins, who I believe is one of the most avid soy supporters out there. He brings up dozens of points, and even mentions me in the article, so I thought refuting his article would be a good way to answer the other critics out there as well.

Lowering Cholesterol

Robbins ascribes soy's potential to lower cholesterol as beneficial. However, while this may be helpful in some, it can be certainly cause disease in others. Low cholesterol does not necessarily imply good health. Please review some of the well-documented dangers of low cholesterol if you are not familiar with them

This is because we all need cholesterol and levels below optimal can cause serious problems. Much of the hype about cholesterol has been generated by self-serving research used to support the massive profit structure of pharmaceutical companies supplying drug-based "solutions."

For example, I happen to have a genetically low cholesterol and it has been as low as 75 at times. This is very dangerous and it took me many years to understand how to normalize it and now my cholesterol is about 100 points higher and a far healthier 175.

Robbins also says, "Soy beverages are cholesterol-free, while cow's milk contains 34 mg of cholesterol per cup, which again means that cow's milk is far worse for your heart and cardiovascular system." This is not a strong argument for soy, as, again, we all need cholesterol--without it we suffer major health problems. It is also important to realize that I do not advocate drinking commercial milk, only non-pasteurized raw milk if one is able to tolerate it.

Animal Study Circular Arguments

Robbins cites a number of studies to support the concept that different animal species respond uniquely to soy or other variables. No argument here.

But, Robbins uses a circular argument that doesn't hold water by giving examples of drugs that were safe in animals but dangerous in humans. For instance:

"When the arthritis drug Opren was tested on monkeys, no problems were found, but it killed 61 people before it was withdrawn. Cylert was fine for animals, but when it was given to hyperactive children it caused liver failure."

This doesn't prove the converse that soy that is safe in animals is safe in humans.

Phytic Acid

According to Mary Enig and Sally Fallon, soybeans are high in phytic acid, which, in large amounts, can block the uptake of essential minerals like calcium, magnesium, copper, iron and especially zinc in the intestinal tract. This is one area where I disagree with Enig and Fallon partially in that the phytic acid in soy (and other plant products like beans, nuts and seeds) may be beneficial or detrimental, it just depends.

For men phytic acid is probably very helpful as nearly all adult males have excess iron as we never had menstrual periods. I personally take a phytic acid supplement to lower my iron levels. However, in menstruating women and children the phytic acid in soy can be a serious negative.

In his arguments Robbins correctly points out that fermented soy products have lower phytic acid than commercial soy products. However, he does so as to contradict Fallon and Enig, but this is exactly what they also state. They have no problems with fermented soy products and encourage their consumption.

Osteoporosis

Robbins' comments that people consuming soyfoods have reduced rates of osteoporosis are a red herring as there are many factors other than soy consumption that are far more powerful influences on optimal bone density. I actually have a book in progress in this area.

For instance, vitamin K is one of the most important nutritional interventions for improving bone density and vitamin K2, which is made in your body and also produced by fermented foods, is a superior form. Fermented soy products may indeed be beneficial, but the typical store-bought soy, like soy meat substitutes, soy milk, soy ice cream and so on, will not produce this effect. You can also get this beneficial form of vitamin K by making your own fermented foods.

Cancer

I would never recommend or encourage non-fermented soy for cancer prevention. However, you can certainly include fermented soy as part of a healthy diet that contributes to cancer prevention.

The exception here is if you already have cancer. In this case, certain constituents from soy can certainly be used therapeutically to help treat the cancer, but that is a completely different application than consuming commercial soy products.

Even Robbins admits that it is wise to avoid large doses of isoflavones:

"When manufacturers of soy protein isolates and supplements recommend that people consume 100 grams of soy protein a day (the equivalent of 7 or 8 soyburgers), they are ignoring the unknown effects of overdosing on isoflavones. I believe it's probably safer, until more is learned, to avoid concentrated soy supplements entirely."

Birth Defects

At least one study has found that soy phytoestrogens appear to increase the risk of birth defects by as much as 500 percent. Further, soy formula exposes infants to very high levels of hormones that can have negative influences on them as they grow older.

The link between soy and birth defects does need to be studied further, as this connection may or may not be true. However, the uncertainty of the association in no way detracts from the other arguments presented here and in other sources against the use of non-fermented soy.

Alzheimer's Disease

One study of close to 4,000 elderly Japanese-American men found that those who ate the most tofu during midlife had more than double the risk of later developing Alzheimer's disease.

Similar to the birth defects and soy argument above, soy may or may not increase the risk of Alzheimer's, as more studies should be done to truly prove this association. But whether or not this is true does not make non-fermented soy any better to consume.

Soy Formula

This is the most critical issue in the entire soy debate, and even Robbins states that "In my view, there is some basis here for concern."

However, because of his pro-soy stance he fails to document just how bad soy formula is for infants. He mentions that "a major study published in the August, 2001, Journal of the American Medical Association found that infants fed soy formula grow to be just as healthy as those raised on cow's milk formulas." Dr. Enig wrote a rebuttal to this study that is most helpful.

Aluminum

In his earlier argument on Alzheimer's Robbins freely admits the connection of aluminum to Alzheimer's, yet he fails to understand that soy has 11 times (1100 percent) more aluminum than traditional formula.

Does that mean everyone should switch to regular formula? Absolutely not as that is based on pasteurized dairy and is fraught with its own complications. Robbins incorrectly asserts "the anti-soy crusader Sally Fallon would evidently prefer that an infant be fed a cow's milk formula rather than breastmilk." Nothing could be further from the truth. Fallon is a strong proponent of breastfeeding, and if that is not possible advocates using NON-pasteurized whole cow or goat milk supplemented according to this homemade formula recipe.

Manganese

Soy formula is loaded with excessive levels of manganese.

The reason manganese is such a concern is that it can be toxic in very high levels, even though it is essential for life, as it helps cells gather energy. For instance, high manganese can contribute to brain damage like Parkinson's disease. The levels of manganese differ considerably in different infant foods:

  • Breast milk contains 4 to 6 micrograms per liter (mcg/L)
  • Milk-based infant formula contains about 30 to 50 mcg/L
  • Some soy formula contain 200 to 300 mcg/L

Not Enough Vitamin A

Robbins in his defense of soy cites an incorrect fact: "Vitamin A is plentiful in plant-based diets."

Once again, nothing could be further from the truth. There is no vitamin A in plant-based diets, only beta-carotene precursors. While beta carotenes are essential for health they are not the same as vitamin A, as that is only available from animal-based foods. Vitamin A deficiencies can certainly lead to problems.

The Saturated Fat Myth

Robbins also says that cow's milk provides more than nine times as much saturated fat as soy beverages, so is far more likely to contribute to heart disease. This is another myth. Saturated fat is essential for human health and not the evil that many portray it to be.

Too Much Omega-6

According to Robbins, "Soy beverages provide more than 10 times as much essential fatty acids as cow's milk, and so provide a far healthier quality of fat."

This is pure nonsense and demonstrates he has not done his homework on fatty acid physiology. Yes, soy has essential fats, but they are the WRONG type. It is loaded with omega-6 and that is the wrong type for nearly everyone.

Around the year 1900 we consumed less than one pound of vegetable fat per person per year, but by 2000 that had increased to over 75 pounds of vegetable fat per year. Nearly all vegetable fat is loaded with omega-6 fats and it's the ratio of omega-6 to omega-3 fats that determines ideal health. Ideally, our ratio of omega-6 to omega-3 should be 1:1, but most Americans eat a dietary ratio that falls between 20:1 and 50:1.

Genetically Modified Soy

Even Robbins capitulates here. How could he do anything but when over two-thirds of the U.S. soy crop is genetically modified. He says:

"According to Monsanto's own tests, Roundup Ready soybeans contain 29 percent less of the brain nutrient choline, and 27 percent more trypsin inhibitor, the potential allergen that interferes with protein digestion, than normal soybeans. I find it fascinating that compared to regular soybeans, the genetically engineered beans have more of the very things that are problematic, and less of the very things that are beneficial. To my eyes, this is certainly another reason to eat organic foods whenever possible. The best way to insure that any soyfoods you eat are not genetically engineered is if they are organically grown."

His conclusion really tends to support the bulk of my position on soy:

"The hype has also made us forget something important. We are eating soy products today at levels never before seen in history. Advances in food technology have made it possible to isolate soy proteins, isoflavones, and other substances found in the bean, and add them to all kinds of foods where they've never been before. The number of processed and manufactured foods that contain soy ingredients today is astounding.

It can be hard to find foods that don't contain soy flour, soy oil, lecithin (extracted from soy oil and used as an emulsifier in high-fat products), soy protein isolates and concentrates, textured vegetable protein (TVP), hydrolyzed vegetable protein (usually made from soy) or unidentified vegetable oils. Most of what is labeled "vegetable oil" in the U.S. is actually soy oil, as are most margarines. Soy oil is the most widely used oil in the U.S., accounting for more than 75 percent of our total vegetable fats and oils intake. And most of our soy products are now genetically engineered.

This has never before been done in human history. It is an experiment, and should be undertaken, if at all, with great humility, watchfulness, and caution. Instead, under the influence of an almost mystical belief in soy's virtues, we've tended to fall prey to an illusion that has haunted American culture in all kinds of ways--the illusion that if a little is good, then surely more must be better."

Soy and the Asian Diet

Asians tend to live longer than Americans, and they traditionally eat more soy than Americans. Thus, the link between the two is one of the most widely circulated reasons why soy must be healthy.

This theory is flawed, first off because soy in the Asian diet is primarily fermented soy, NOT the highly processed soy protein isolate, soy isoflavones and so on that make up soy in the American diet. There is a huge difference in this respect alone.

However, although there are many reasons why Asians typically live longer than Americans, I believe the primary one has nothing to do with their soy consumption but rather with the ratio of their omega-6:omega-3 fat consumption. The Asian ratio is 3:1 while in the United States, as I mentioned above, the ratio ranges from 20:1 to 50:1. Many Paleolithic experts believe it should be close to 1:1 for ideal health.

Traditionally, the Japanese have eaten plenty of clean fish, which is likely what contributed to their healthy fat ratio. But we are already starting to see the longevity of the Japanese decrease, and I suspect that it is due to the contamination of the fish supply with heavy metals like mercury and chemicals like PCBs.

Soy Industry

One fact that Robbins remains oblivious to is that the edible oil industry is a multibillion-dollar industry that is in many ways similar to the pharmaceutical industry. They have funded much of the research to support a strong soy recommendation so they can directly benefit from the increased sales of soy in this country.

To Wind Things Up

Clearly many people seem to improve when they start to include soy in their diet, but I don't believe this is an argument for soy. My guess is that this is likely more related to what people have excluded from their diet to make room for the soy.

I want to reemphasize here that I am in no way opposed to soy consumption, only improper soy consumption.

I firmly believe that fermented soy, which includes natto, miso, tempeh and soybean sprouts, is a health food for most and should be consumed by the masses. However, soy formula is an abomination that has caused much damage to the children of this country and should be immediately banned for sale in every country.

For even more information on soy and health, I encourage you to look through the links below and also to use the search feature on this site. You will find numerous studies on the topic that will help you to make an informed decision about soy for yourself.

Related Articles:

Why Soy Can Damage Your Health

How Safe is Soy Infant Formula?

Caution Urged on Soy Menopause Remedies

Soy Formula: The Popular Food You Should Never, Ever Feed Your Baby

Low Cholesterol and Suicide Risk

Soy: Too Good to be True

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