Herbs in alphabetical order
Soy Isoflavone Concentrate
Soy isoflavone concentrate is taken from
the beans of the soy plant.
The soybean contains several medicinally useful
chemicals, including isoflavones and lecithin. The isoflavones most
recognized as beneficial are daidzein and genistein, and the
closely related compounds daidzin and genistin. These
substances have been well researched for their antioxidant
and phytoestrogenic properties.
Soy isoflavones are used medicinally primarily because of
their estrogen-regulating properties.
Benefits of soy isoflavones for specific health conditions
include the following:
- Alzheimer's disease. Estrogen is believed to slow the
production of amyloid plaques in the brain and help preserve
memory, two problems closely associated with Alzheimer's
disease. Thus, soy isoflavones may help slow the progress
of Alzheimer's disease.
- Atherosclerosis. Soy
isoflavones prevent the formation of atherosclerotic plaques within
- Cancer. Because of its estrogen like properties, soy has
been shown to reduce the risk of hormone-dependent
cancers, such as breast and prostate cancers, as well as the risk
of other types of cancer. The similarity of soy isoflavones to
the human hormone estrogen allows isoflavones to attach to
estrogen receptors in human cells. This blocks actual human
estrogen from doing the same. The isoflavones are just
different enough from estrogen, however, that they do not
stimulate cells as estrogen does. This keeps estrogen away
from cells that are sensitive to estrogen, especially
cancerous cells in the bladder, breast, colon, prostate, and skin.
Daidzein is one such estrogen-blocking isoflavone. It
locks out estrogen from breast-cancer cells without
stimulating the cells to reproduce. It also fights cancer by causing
immature tumor cells to differentiate, or mature into forms
that have normal life spans and are then replaced. Daidzein
has been shown to be very potent in forcing differentiation
of human leukemia cells and of melanoma cells, even when
absorbed in very low concentrations.
Finnish researchers conducted decades of exacting
studies to explain why the people of Japan enjoy lower rates of
breast, ovarian, prostate, and other cancers. They
identified genistein as the common denominator. Genistein is
especially valuable in reversing cancer risk associated with
certain kinds of obesity in women. Women who are
physically inactive and have a genetic tendency toward
often develop insulin resistance, a condition in which the
body is forced to produce more and more insulin to
transport glucose to the cells where it is needed. In addition to
regulating blood sugar, insulin facilitates the transport
of fat into fat cells, and fatty tissue produces estrogen.
Thus, insulin indirectly activates estrogen and progesterone
receptors, an action that stimulates the growth of cells,
including estrogen-activated cancer cells. Since genistein
blocks estrogen from its receptors on cells, it helps fight the
cancer-promoting effects of excess estrogen production.
Genistein counteracts cancer development on several
levels. It deactivates a harmful protein called tyrosine
protein kinase, a key player in stimulating cell growth. This
keeps cancer cells from multiplying. Genistein also affects
other key enzymes involved in the cancer-formation
process. Like daidzein, genistein causes cancer cells to
differentiate, stopping wild multiplication. In addition, genistein
stops the process by which tumors develop their own
systems of blood vessels. This action deprives cancer cells of
nutrients and oxygen, keeping them small. There is also
evidence, at least in the case of certain kinds of
that genistein complements the action of the gene p53, a
"patrol gene" that deactivates cancer cells.
- Diabetic retinopathy. The genistein content of soy
isoflavones allows them to fight the development of diabetic
retinopathy, an eye disorder that is a complication of diabetes.
menopause-related problems, and
Through their estrogenic action, soy isoflavones help move
calcium from the bloodstream into the bones,
strengthening their resistance to fracture. The mild estrogenic activity
of soy isoflavones may ease menopause symptoms for
some women, without creating estrogen-related problems,
as well as having a positive effect in the prevention of
osteoporosis. A series of clinical trials around the world has
established that soy isoflavones are a useful and safe
alternative to estrogen therapy in treating low bone mass or
osteoporosis in women who have passed menopause.
- Psoriasis. The genistein in soy reduces the formation of
keratin, a skin protein associated with psoriasis.
The easiest way to get soy isoflavones is by taking soy
isoflavone concentrate. Soy germ also can be used, as can cooked
soybeans, miso, or tofu (soybean curd). Soy isoflavones are
also found in the herb kudzu. Of readily available soy foods, roasted
soybeans have the highest isoflavone content, about 167
milligrams for a 3.5-ounce serving. Tempeh is next, with 60
milligrams, followed by soy flour with 44 milligrams.
Processed soy products such as soy protein and soymilk
contain about 20 milligrams per serving. Although the
optimum dosage of isoflavones obtained from food is not
known, one study found that ingesting 62 milligrams of
isoflavones daily is sufficient to reduce cholesterol.
Further, we know that Japanese women eat up to 200
milligrams of isoflavones from soy foods daily.
Although it is not a purely herbal product, ipriflavone, a
chemically altered form of soy isoflavones, is a better
choice for preventing and treating osteoporosis, and for
preventing bone fractures in weight lifters and participants
in contact sports. Clinical testing in Japan has found that
treatment with ipriflavone, even without supplemental calcium, prevents bone
loss better than calcium supplementation alone.
Because isoflavones work somewhat like estrogen, there
are concerns that they may not be safe for women who
already have breast cancer. Preliminary studies and reports
have raised concerns that intensive use of soy products by
a pregnant woman could exert a hormonal effect that has
an impact on the developing fetus. Soy isoflavones could
theoretically interfere with the action of oral
contraceptives, although studies have not confirmed this.
Soy products may impair thyroid function or reduce
absorption of thyroid medication, at least in children.
People with impaired thyroid function should use soy in
moderation or under medical supervision.