Lowdown on Soy as a protein source

It's not as good for you as we thought.

The Chinese did not eat unfermented soybeans as they did other legumes such

as lentils because the soybean contains large quantities of natural toxins or

"anti-nutrients". First among them are potent enzyme inhibitors that block

the action of trypsin and other enzymes needed for protein digestion. These

inhibitors are large, tightly folded proteins that are not completely

deactivated during ordinary cooking. They can produce serious gastric

distress, reduced protein digestion and chronic deficiencies in amino acid

uptake. In test animals, diets high in trypsin inhibitors cause enlargement

and pathological conditions of the pancreas, including cancer. Soybeans also

contain haemagglutinin, a clot-promoting substance that causes red blood

cells to clump together.

Trypsin inhibitors and haemagglutinin are growth inhibitors. Weanling rats

fed soy containing these antinutrients fail to grow normally.

Growth-depressant compounds are deactivated during the process of

fermentation, so once the Chinese discovered how to ferment the soybean,

began to incorporate soy foods into their diets. In precipitated products,

enzyme inhibitors concentrate in the soaking liquid rather than in the curd.

Thus, in tofu and bean curd, growth depressants are reduced in quantity but

not completely eliminated. Soy also contains goitrogens - substances that

depress thyroid function.

Soybeans are high in phytic acid, present in the bran or hulls of all seeds.

It's a substance that can block the uptake of essential minerals - calcium,

magnesium, copper, iron and especially zinc - in the intestinal tract.

Although not a household word, phytic acid has been extensively studied;

there are literally hundreds of articles on the effects of phytic acid in the

current scientific literature. Scientists are in general agreement that

grain- and legume-based diets high in phytates contribute to widespread

mineral deficiencies in third world countries. Analysis shows that calcium,

magnesium, iron and zinc are present in the plant foods eaten in these areas,

but the high phytate content of soy- and grain-based diets prevents their

absorption. The soybean has one of the highest phytate levels of any grain or

legume that has been studied, and the phytates in soy are highly resistant to

normal phytate-reducing techniques such as long, slow cooking. Only a long

period of fermentation will significantly reduce the phytate content of

soybeans. When precipitated soy products like tofu are consumed with meat,

the mineral-blocking effects of the phytates are reduced. The Japanese

traditionally eat a small amount of tofu or miso as part of a mineral-rich

fish broth, followed by a serving of meat or fish.

Vegetarians who consume tofu and bean curd as a substitute for meat and dairy

products risk severe mineral deficiencies. The results of calcium, magnesium

and iron deficiency are well known; those of zinc are less so. Zinc is called

the intelligence mineral because it is needed for optimal development and

functioning of the brain and nervous system. It plays a role in protein

synthesis and collagen formation; it is involved in the blood-sugar control

mechanism and thus protects against diabetes; it is needed for a healthy

reproductive system. Zinc is a key component in numerous vital enzymes and

plays a role in the immune system. Phytates found in soy products interfere

with zinc absorption more completely than with other minerals. Zinc

deficiency can cause a "spacey" feeling that some vegetarians may mistake for

the "high" of spiritual enlightenment.

Milk drinking is given as the reason why second-generation Japanese in

America grow taller than their native ancestors. Some investigators postulate

that the reduced phytate content of the American diet - whatever may be its

other deficiencies - is the true explanation, pointing out that both Asian

and Western children who do not get enough meat and fish products to

counteract the effects of a high phytate diet, frequently suffer rickets,

stunting and other growth problems.


Soy processors have worked hard to get these anti-nutrients out of the

finished product, particularly soy protein isolate (SPI) which is the key

ingredient in most soy foods that imitate meat and dairy products, including

baby formulas and some brands of soy milk.

SPI is not something you can make in your own kitchen. Production takes place

in industrial factories where a slurry of soy beans is first mixed with an

alkaline solution to remove fibre, then precipitated and separated using an

acid wash and, finally, neutralised in an alkaline solution. Acid washing in

aluminium tanks leaches high levels of aluminium into the final product. The

resultant curds are spray- dried at high temperatures to produce a

high-protein powder. A final indignity to the original soybean is

high-temperature, high-pressure extrusion processing of soy protein isolate

to produce textured vegetable protein (TVP).

Much of the trypsin inhibitor content can be removed through high-temperature

processing, but not all. Trypsin inhibitor content of soy protein isolate can

vary as much as fivefold. (In rats, even low-level trypsin inhibitor SPI

feeding results in reduced weight gain compared to controls.) But

high-temperature processing has the unfortunate side-effect of so denaturing

the other proteins in soy that they are rendered largely ineffective. That's

why animals on soy feed need lysine supplements for normal growth. Nitrites,

which are potent carcinogens, are formed during spray-drying, and a toxin

called lysinoalanine is formed during alkaline processing. Numerous

artificial flavourings, particularly MSG, are added to soy protein isolate

and textured vegetable protein products to mask their strong "beany" taste

and to impart the flavour of meat. In feeding experiments, the use of SPI

increased requirements for vitamins E, K, D and B12 and created deficiency

symptoms of calcium, magnesium, manganese, molybdenum, copper, iron and

zinc. Phytic acid remaining in these soy products greatly inhibits zinc and iron

absorption; test animals fed SPI develop enlarged organs, particularly the

pancreas and thyroid gland, and increased deposition of fatty acids in the

liver. Yet soy protein isolate and textured vegetable protein are used

extensively in school lunch programs, commercial baked goods, diet beverages

and fast food products. They are heavily promoted in third world countries

and form the basis of many food giveaway programs.

In spite of poor results in animal feeding trials, the soy industry has

sponsored a number of studies designed to show that soy protein products can

be used in human diets as a replacement for traditional foods. An example is

"Nutritional Quality of Soy Bean Protein Isolates: Studies in Children of

Preschool Age", sponsored by the Ralston Purina Company. A group of Central

American children suffering from malnutrition was first stabilised and

brought into better health by feeding them native foods, including meat and

dairy products. Then, for a two-week period, a drink made of soy protein

isolate and sugar replaced these traditional foods. All nitrogen taken in and

all nitrogen excreted was measured in truly Orwellian fashion: the children

were weighed naked every morning, and all excrement and vomit gathered up

for analysis. The researchers found that the children retained nitrogen and that

their growth was "adequate", so the experiment was declared a success.

Whether the children were actually healthy on such a diet, or could remain so

over a long period, is another matter. The researchers noted that the

children vomited "occasionally", usually after finishing a meal; that over

half suffered from periods of moderate diarrhoea; that some had upper

respiratory infections; and that others suffered from rash and fever.

It should be noted that the researchers did not dare to use soy products to

help the children recover from malnutrition, and were obliged to supplement

the soy-sugar mixture with nutrients largely absent in soy products -

notably, vitamins A, D and B12, iron, iodine and zinc.


Click here: article26</A>: ARE SOYA PRODUCTS HEALTHY?

I found this in: http://www.worldwidehealthcenter.net/

Alternative and Complementary Medicine Directory

For much, much more about soy and the soy industry, click here:


Soy Online Service Home Page

Now to the demanding task of reversing the damage done.