Writings about the soybean date back to 3000
B.C., when the Emperor of China listed the virtues of soybean
plants for regenerating the soil for future crops. His praises
centered on the root of the plant, not the bean. These ancient
writing suggested that the Chinese recognized the unfitness
of soybeans for human consumption in their natural form. Now
5000 years later, we are once again catching on to the anti-nutritive
qualities of the soybean, and realizing that the only soybean
worth eating is one that has been fermented.
The key to releasing the nutrients of the soybean has been
known for thousands of years
About 1000 B.C. some smart person in China discovered that a
mold, when allowed to grow on soybeans, destroyed the toxins
present and made the nutrients in the beans available to the
body. This process became known as fermentation and led to the
creation of the still popular foods tempeh, miso, and natto.
A few centuries later, a simpler process was developed to prepare
soybeans for consumption. After lengthy soaking and cooking,
the beans were treated with nigari, a substance found in seawater.
The end product was tofu. During the Ming dynasty, fermented
appeared in the Chinese Materia Medica as a nutritionally
important food and an effective remedy for diseases.
Unfermented soybeans contain potent anti-nutrients
In their natural form, soybeans contain phytochemicals with
toxic effects on the human body. The three major anti-nutrients
are phytates, enzyme inhibitors and goitrogens.
These anti-nutrients are the way nature protects the soybean
plant so that it can live long enough to effectively reproduce.
They function as the immune
system of the plant, offering protection from the radiation
of the sun, and from invasion by bacteria, viruses, or fungi.
They make the soybean plant unappetizing to foraging animals.
All plants have some anti-nutrient properties, but the soybean
plant is especially rich in these chemicals.
If they are not removed by extensive preparation such as fermentation
or soaking, soybeans are one of the worst foods a person can
Unfermented soy has been linked to digestive distress, immune
system breakdown, PMS, endometriosis, reproductive problems
for men and women, allergies, ADD and ADHD, higher risk of heart
disease and cancer, malnutrition, and loss of libido.
Groups most at risk of experiencing negative effects from the
anti-nutrient properties of soy are infants taking soy baby
formula, vegetarians eating a high soy diet, and mid-life women
going heavy on the soy
foods thinking they will help with symptoms of menopause.
Soybeans contain high levels of phytates
All legumes contain phytate (also known as phytic acid) to some
extent, but the soybean is particularly rich in this anti-nutrient.
Phytate works in the gastrointestinal tract to tightly bind
minerals such as zinc, copper,
iron, magnesium and calcium. It has a particularly strong affinity
a mineral that supports wound healing, protein synthesis, reproductive
health, nerve function, and brain development. It is believed
that people living in developing countries are shorter than
those in developed countries because of zinc deficiency caused
by eating too many legumes. There is also evidence that mental
development can be negatively impacted by a diet high in phytate.
In most legumes such as other varieties of beans, soaking is
enough to break down most of the phytate content. However the
soybean requires that the enzymes be released in the fermentation
process to reduce its phytate content to the point where it
becomes fit for consumption. This means that fermented soy foods
like miso and tempeh have the lowest levels of phytate and are
the best choices for anyone wishing to eat soybean products.
Tofu is also a good choice, as long as care is taken to replenish
Whole soybeans, soy milk, soy chips, soy protein isolates, soy
flour and all the other myriad of products made from processed
soybeans and advertised as health foods have much higher levels
of phytate and are not worth eating.
Unfermented soy products are rich in enzyme inhibitors
When food is eaten, digestive enzymes such as amylase lipase
and protease are secreted into the digestive tract to help break
it down and free nutrients for assimilation into the body. The
high content of enzyme inhibitors in unfermented soybeans interferes
with this process and makes carbohydrates and proteins from
soybeans impossible to completely digest. When foods are not
completely digested because of enzyme inhibitors, bacteria in
the large intestine try to do the job, and this can cause discomfort,
bloating, and embarrassment. Anyone with naturally low levels
of digestive enzymes such as elderly people would suffer the
most from the enzyme inhibiting action of soy.
Soybeans can block production of thyroid
Soybeans have a high content of goitrogens, substances that
can block the production of thyroid hormone as well as cause
goiter formation. Low thyroid activity plagues women in America,
particularly middle-aged women. Thyroid hormone stokes the cellular
furnaces, known as mitochrondia. When thyroid production is
low, energy levels as well as body heat are also low. Low thyroid
level is what makes old people move so slowly and seem like
every action is a huge chore. Low thyroid means the action of
the heart is reduced, resulting in lack of oxygen to the cells,
a prime condition for cancer.
Genistein, an isoflavone found in soybeans, can also block thyroid
production. Phytate can accentuate these effects because it
binds up zinc and copper, leaving little of these important
minerals available to make thyroid hormone.
A transport protein called GLUT1 is shut down by genistein.
This protein sends glucose into the cells where it is used to
generate energy. Slowing the transport of glucose means less
energy production not only of thyroid hormone, but of every
other action in the body.
Another way in which soy isoflavones
reduce energy in the body is by inhibiting tyrosine kinases,
enzymes involved in the transfer of energy from one molecule
to another. These enzymes drive cell division, memory consolidation,
tissue repair, and blood vessel maintenance and regeneration.
It is this action of regulating cell division that made genistein
a popular substance for fighting cancer. When research on this
anti-cancer effect of genistein became know, the soy industry
feverishly developed products that would appeal to Western women
looking for genistein. In the middle of all this excitement,
little attention was paid to how the energy reducing effects
of genistein lowered cellular energy in normal cells.
The benefits of genistein come at a high cost
Women have been encouraged to use high genistein soy products
to alleviate symptoms of menopause and as a guard against bone
loss and breast
cancer. But given the full range of effects of genistein
in the body, high consumption could result in age-related memory
loss. Commercial soybean products offer genistein levels as
high as 20 to 60 mg per serving. Asians are presented as an
example of the benefits of eating soybean products because their
incidence of breast cancer and osteoporosis is low. However,
the Asian diet of fermented soybean products such as miso and
tempeh includes only around 5 mg of genistein a day.
Genistein slows the growth of blood vessels to tumors, another
action that makes it popular as a cancer fighter. However, it
has the same effect on blood vessels serving normal cells. Eating
a regular diet high in genistein could result in the starvation
of healthy blood vessels, resulting in a reduced supply of oxygen
to cells, setting up a cancer promoting situation.
In a graphic example of how genistein slows cellular energy,
a study found that eating high levels of it slowed hair growth
by 60 to 80 percent
A decade ago a study of 8,000 Asian men showed that those consuming
the highest amounts of tofu had smaller brain size and nearly
three times the rate of senile dementia as those who ate the
lowest amounts. These results suggest that eating foods high
in isoflavones such as soy protein isolates may accelerate the
aging of the brain.
Fermentation releases nutrients and transforms soybeans into
People filling up their shopping carts with raw or cooked soybeans,
milk, and other non-fermented soybean products do not realize
that the isoflavones they contain will not be available to their
bodies. Most of the isoflavones in soy products are bound to
carbohydrate molecules called glucosides. In this form genistein
is actually called genistin. It is fermentation that transforms
genistin into genistein. Many products in the U.S. do not distinguish
between genistin and genistein on their labels.
Even with fermented soy foods, a little goes a long way. The
nutrients found in miso, tempeh, and natto can be beneficial
in the moderate amounts found in the typical Asian diet, but
have the potential to do harm in higher amounts. In China and
Japan, about an ounce of fermented soy food is eaten on a daily
When fermented soy foods are used in small amounts they help
build the inner ecosystem, providing a wealth of friendly microflora
to the intestinal tract that can help with digestion and assimilation
of nutrients, and boost immunity.
Dr. John Lee, author of several books on the health of women,
recommended that women wishing to consume soy production eat
only miso, tempeh, natto. Tofu can also be eaten provided it
is accompanied by fish or some other protein source and some
seaweed or kelp to replenish bound minerals. Eating small amounts
of these foods will provide the cancer protective effects of
genistein without causing the other potential problems of genistein.
Dr. Lee recommended avoiding genistein and isoflavone supplements,
and soy protein isolates.