Isoflavones and Phytoestrogens
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Phytoestrogens
Plants contain numerous chemical compounds (also known as phytochemicals)
that are vital to their function. When it is observed that certain plants
have beneficial effects such as preventing disease or curing disease, scientists
attempt to discover what phytochemical or groups of phytochemicals are responsible
for these positive effects. One type of phytochemical that has interested
scientists is known as phytoestrogens.
Phytoestrogens are non-steroidal phytochemicals that exert weak,
estrogen-like effects on the body. One group of phytoestrogen
that has been observed to have and shown
experimentally to exert positive effects is known as
isoflavones.
Isoflavones
The most well-known isoflavones are Daidzein, Genistein and Glycitein.
As discussed in detail on the
Benefits of Soy web page, these isoflavones are found in soyfoods and
are believed to be largely responsible for soy's ability to help prevent some
forms of cancer, heart disease, and perhaps help prevent osteoporosis and
menopausal symptoms. These isoflavones are found in large amounts in soy products
and in much smaller amounts in other legumes. [See
USDA-Iowa State University Database on the Isoflavone Content of Foods - 1999.]
The isoflavone, genistein, has been shown to inhibit breast
and prostate cancer cell growth. Another group of phytoestrogens found
in soyfoods, lignans is also believed to have some anti-cancer
effects. The isoflavone, daidzein, has been found to enhance bone
formation leading scientists to believe that it may help prevent and treat
osteoporosis. Genistein has been shown to prevent bone loss in animals.
Use of Soy Products
Scientists are capable of isolating the effects of some phytochemicals
found in soy products. However, positive health effects from ingesting
plants are almost always due to a combination of the phytochemicals in
those plants. Clinicians who have extensive experience using plants to
help patients prevent and heal disease have found that
there are almost always major drawbacks to giving isolated phytochemicals
to patients as opposed to the giving them the whole plant (or an extract
of all of the phytochemicals). A couple of the drawbacks of using
isolated phytochemnicals include:
- Much greater likelihood of adverse reactions including subtle and detrimental
long-term health problems which can appear months or years later.
- The positive effects from the isolated phytochemical use often appear
more quickly, but this positive change is often not long-lasting
after the intake of the isolaed phytochemical is stopped.
When an isolated phytochemical comes on the market, it is often heavily-hyped
by certain organizations and by the media and then forgetten about several
months or years later after the positive effects do not match the hype.
Soy Foods Online! suggests focusing on the use of traditional
soy products (tofu, tempeh, miso, natto, tamari, soy milk, shoyu) to help
prevent disease rather than taking isolated phytochemicals. These traditional
soy products have had centuries of use. Clinical and epidemiological
evidence has shown disease prevention effects without any significant
adverse effects from life-long intake.
http://www.soyinfo.com/isoflav.shtml