is a class of hormones present in women's bodies that induces
menstruation and female characteristics such as the development
of ovaries and
breasts. It is produced by the ovaries. During menopause,
the ovaries stop functioning and the body stops producing
estrogen. This can have long-range effects including osteoporosis
It may also cause symptoms such as hot flashes, irritability
and depression. Various forms of estrogen can be taken as
drugs to offset these symptoms. However, because estrogen
alone can cause a high risk of breast cancer, estrogen is
usually prescribed in combination with progestin
to lower the risk. This combination is called hormone
replacement therapy (HRT). HRT may reduce the risk of
osteoporosis and heart disease, but may increase the risk
of breast cancer and liver disease.
Estrogen has many effects on brain chemistry
and behavior. In animals, estrogen can increase the formation
of new connections between neurons,
which may be one way that the brain stores new information
during learning. Female rats given estrogen may learn tasks
faster than female rats deprived of estrogen. There is some
evidence that women with low levels of estrogen may show impaired
thought processes and increased risk of developing Alzheimer's
disease. Post-menopausal women taking HRT may show a reduced
risk of Alzheimer's disease. However, there is not yet enough
evidence from large-scale studies to be certain. Given that
estrogen (and HRT) are associated with some serious risks,
most doctors do not feel that estrogen should be taken solely
for the purpose of protection against Alzheimer's disease.
Instead, women should balance the known risks and benefits
of estrogen, such as osteoporosis, cancer and heart disease.
To avoid some of the known risks of estrogen,
some women take phytoestrogens, or plant-based estrogens.
These are found in foods such as whole grains, beans and soy
or in dietary supplements marketed as "natural" estrogen.
At this point, it is not at all clear what benefits and risks
are associated with these phytoestrogens. In fact, it is possible
that taking phytoestrogen supplements may carry the same long-term
risk of cancer as estrogen alone (see estrogen
replacement therapy). Until the safety of these supplements
is established, their long-term effects are unknown.
However, there is little risk associated
with eating a phytoestrogen-rich diet, since the associated
foods (whole grains, beans and soy) have many health benefits
-- some totally unrelated to estrogen. Meanwhile, research
is underway to document what, if any, risks and benefits are
associated with phytoestrogens.
Article : "ESTROGEN
by Catherine E. Myers. Copyright © 2006 Memory Loss and the Brain