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Flax Lignans for Womens Health |
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Menopause
Flax lignans provide significant health benefits for women. Because lignans are phytoestrogens, they have the potential to help reduce symptoms of menopause. One study found that 40 grams of crushed flaxseed per day was as effective as HRT in alleviating mild menopausal systems.
Breast Health
Early research also
suggests lignans may
protect against hormone
related cancer
such as breast cancer.
Protective effects have
been shown in rats fed
flaxseed or purified
SDG from flax. As previously
discussed, SDG
is the main lignan
found in flaxseed and
when consumed is
converted to mammalian
lignans,
enterolactone and
enterodiol, that are
responsible for administering
the many
health benefits to the
body.
Studies in humans
are also suggestive of
protective effects but
are not conclusive at
this point. Observation
studies have found
that breast cancer
patients and people at
high risk of breast
cancer excrete less
mammalian lignans
than people with a
lower risk of breast
cancer. A study in
Finland found that
women with high
enterolactone levels in
their blood had a
lower risk of breast
cancer. High levels of
enterolactone (a mammalian
lignan) indicate
increased dietary
intake of plant lignans,
such as SDG.
These studies suggest
that eating a diet rich
in lignans may be protective
against breast
cancer.
 A recent human
clinical trial examined
the effects of flaxseed
on estrogen metabolism
in 28 postmenopausal
women.
Researchers looked at
two pathways of
estrogen metabolism
involving the production
of different
estrogen metabolites.
The ratio of these
metabolites is used as a
marker for breast
cancer risk. The
women were given 0, 5
or 10 grams of ground
flaxseed a day for
seven weeks. Those
who ate flaxseed had
an improved ratio of
estrogen metabolites,
suggesting that
flaxseed has protective
effects against cancer in postmenopausal
women. The higher
doses of flax led to a
greater positive
response. A similar
study was carried out,
this time in 16 premenopausal
women.
Again ten grams of
flaxseed per day was
given and found to
improve the ratio of
estrogen metabolites,
suggesting a chemoprotective
effect in
premenopausal
women.
A preliminary study
of 39 women with
newly-diagnosed
breast tumors examined
the effects of
flaxseed on breast
cancer growth.
Women were randomized
to eat daily a
muffin containing 0
or 25 grams of flaxseed
for a little over a
month. The women
who ate flaxseed
muffins demonstrated
reductions in breast
cell proliferation and
tumor growth at a rate
similar to effects seen
with tamoxifen (a
breast cancer drug)
treatments.
Authors of the
above studies indicate
that lignans played a
role, although it was
not directly proven
that lignans were the
only compounds producing
the beneficial
effects. However, lignans
have been shown
to inhibit estrogenstimulated
growth of
breast cancer cells in a
test tube. In addition,
purified lignans from
flax (SDG) were shown
to inhibit tumor
growth in rats. These
results suggest that
lignans do play a significant
role in the
anticancer activity of
flaxseed. These studies
discussed are not concrete
proof that
women who eat
flaxseed are less likely
to get breast cancer.
However, evidence is
accumulating that lignans
do contribute to
breast health.
Flax lignans may
promote breast health
by acting as a phytoestrogens
and also by
acting as antioxidants.
In addition, research
also suggests that flax
and its lignans may
decrease angiogenesis
or the growth of
blood vessels that
supply oxygen and
nutrients to tumors
for growth.
Bone Health
Research further indicates
that lignans may
promote and support
bone health. It is
known that hormone
deficiency is a risk
factor for osteoporosis
in postmenopausal
women. As phytoestrogens,
lignans are
reported to possesses
both weak estrogenic
and antiestrogenic
activities and may be a
natural alternative for
women in preserving
bone health. A study
to examine the effects
of flaxseed on bone
metabolism in postmenopausal
women
who were not on hormone
replacement
therapy stated that,
“observations suggest
flaxseed may exert
positive effects on
bone metabolism by
reducing the rate of
bone reabsorption,
resulting in a net bone
gain.” Additionally, its
positive effects on
bone metabolism may
be through improved
antioxidant status.
However, in a followup
study, there was no
effect of flaxseed on
bone metabolism in
postmenopausal
women. Therefore,
more research is
needed to determine
whether longer term
studies with lignans
will have a positive
influence on other
bone measurements
such as bone mineral
density.
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