Lignans and breast cancer
Fruits, meats, and colon cancer
Flavonoids lower heart deaths
Second hand smoke risks
Alcohol, aneurysm, and breast cancer
Meat protein and endometrial cancer
Ask Dr. J: Ipriflavone and hormones
Lignans are estrogen-like compounds found in plant foods
such as seeds, nuts, fruits, vegetables, whole grains, and
beans. Lignans (plant-based estrogens) from non-soy sources
are far more common in the Western diet than those from soy
foods. Flax and sesame seeds contain the far more lignans
than most other good sources. Flax seeds contain 85 mg per
ounce, and sesame seeds contain 11 mg per ounce, while other
food sources contain less than 1 mg per serving.
A study from France, published in the Journal of the National
Cancer Institute, shows that post-menopausal women who consume
large amounts of lignans have a lower risk of breast cancer.
Risk reduction was 17 percent for women with the highest
lignan intake (greater than 1.4 mg per day) compared to those
with the lowest intake. (Touillaud MS, et al., Dietary lignan
intake and postmenopausal breast cancer risk by estrogen
and progesterone receptor status. J Natl Cancer Inst. 2007
This study involved 58,049 post-menopausal women followed
for an average of 7.7 years. Over that time there were a
total of 1469 cases of diagnosed breast cancer. Earlier studies
were unclear on the relationship of lignans to breast cancer,
but in this study, they are clearly helpful in this age group.
After flax and sesame seeds, the best sources of lignans
are brassica family foods (kale, broccoli, and cabbage),
apricots, strawberries, and whole grains. These lignan-rich
foods are also high in fiber, vitamins, minerals, antioxidants,
and other phyto-chemicals that protect against heart disease
and other cancers.
Polyps in the colon are benign growths that have a tendency
to lead to malignancies. Larger polyps are more likely to
harbor malignant cells. A new study shows that a diet high
in fruit and low in meat appears to protect against the development
of colorectal polyps and cancers. In this study, vegetables
or moderate reduction of meat in the diet did not appear
to offer the same protection as the high-fruit, very-low-meat
combination. Other studies have also shown an association
of meat eating with colon cancer.
Researchers at the University of North Carolina evaluated
725 patients who had just had colonoscopies. Those who ate
large or moderate amounts of meat had a 70 percent greater
risk of having polyps found during the examination, compared
to those who ate a lot of fruit and very little meat. (Austin
GL, et al., A diet high in fruits and low in meats reduces
the risk of colorectal adenomas. J Nutr. 2007 Apr;137(4):999-1004.
Flavonoids are plant pigments that have antioxidant activity
and other healthful properties, including reducing both LDL
cholesterol levels and inflammation. A wide variety of these
phytochemicals (also called bioflavonoids) is found in many
plant foods. The Iowa Women’s Health Study reports
that women who had the highest intake of flavonoids had a
lower risk of death from heart disease and a lower incidence
of heart and blood vessel diseases.
The study evaluated 34,489 women over 16 years and specifically
looked at intake of three kinds of flavonoids – anthocyanins,
flavones, and flavanones. Specific foods that were helpful
included bran from whole grains, apples, red wine, pears,
strawberries, and grapefruit. (Mink PJ, et al., Flavonoid
intake and cardiovascular disease mortality: a prospective
study in postmenopausal women. Am J Clin Nutr. 2007 Mar;85(3):895-909.)
Risk reduction ranged from 10 to 22 percent. Although this
may seem small, reducing heart deaths by this amount could
prevent 50 to 100,000 deaths per year in the United States.
Also, adding many small benefits through health habit changes
gives you much greater control of your health future.
While I am skeptical of the value of many meta-analysis
studies (a review of other studies) they are useful on the
occasions when they provide confirmation of the weight of
other evidence or new insights. A meta-analysis of the dangers
of second-hand smoke (environmental smoke) shows that non-smokers
exposed to such smoke have a 24 percent increase in lung
Long-term exposure (30 years) led to a 50 percent increase,
and those considered to be heavily exposed to the smoke of
others (restaurant and bar workers) have a 100 percent greater
risk of developing lung cancer than non-smokers. Researchers
evaluated studies from many countries (Stayner L, et al.,
Lung cancer risk and workplace exposure to environmental
tobacco smoke. Am J Public Health. 2007 Mar;97(3):545-51.)
Passive exposure to tobacco smoke is also associated with
asthma and other respiratory ailments.
The wall of the aorta where it passes through the abdomen
is sometimes weakened and bulges out to form an aneurysm.
This is usually the result of atherosclerosis, and leads
to a life-threatening risk of rupture. A new study shows
that moderate alcohol consumption (two drinks a day) is associated
with an increased risk of developing such aneurysms. (Wong
DR, et al., Smoking, hypertension, alcohol consumption, and
risk of abdominal aortic aneurysm in men. Am J Epidemiol.
2007 Apr 1;165(7):838-45.)
This Harvard study of 39,352 men for 16 years showed that
the aortic aneurysm risk was 21 percent higher when considering
alcohol use at the start of the study. When evaluation of
alcohol consumption was updated every four years, the risk
was 61 percent higher than for non-drinkers.
Another Harvard study shows that as little as one drink
per day increases a woman’s risk of invasive breast
cancer by 9 percent, while two drinks per day (other than
red wine) increases the risk by 43 percent. (Zhang SM, Alcohol
consumption and breast cancer risk in the Women's Health
Study. Am J Epidemiol. 2007 Mar 15;165(6):667-76.) This is
data from the Women’s Health Study of 38,454 subjects
followed for an average of 10 years.
The evidence for the value of reducing or eliminating meat
from the diet is pretty clear by now, and it keeps accumulating.
A study from Shanghai, China showed that the women who consumed
the most protein from animal sources had double the risk
of endometrial cancer as women who consumed the least animal
protein. High levels of animal fat in the diet boosted the
risk by 50 percent. High total calorie intake was also associated
with greater risk. (Xu WH, et al., Nutritional factors in
relation to endometrial cancer: a report from a population-based
case-control study in Shanghai, China. Int J Cancer. 2007
On the other hand, women who consumed most of their protein
from vegetable sources cut their risk by 30 percent. The
study compared 1204 women with newly diagnosed endometrial
cancer with 1212 healthy women. Saturated fat was related
to increased risk, but no association was found with polyunsaturated
fats. The researchers also found that vitamins A, C, and
E, as well as fiber and beta-carotene all reduced the risk,
whether they were derived from food or supplements.
Q: I have been told to take ipriflavone to improve my bone
density, but I am concerned about risks. Will I need to take
progesterone to protect against uterine cancer?
L.B. California, via email
A: Ipriflavone is similar to soy isoflavones but has been
modified to increase its beneficial effect on bone. Depending
on the studies you look at it appears to help rebuild bone
or at least to halt the progression of bone loss. However,
even though it has some similarities to plant-derived estrogens,
it does not have estrogenic effects in the body. I have seen
only one side effect reported, which is a lowered white blood
cell count in a few patients. Whether this is clinically
significant is not clear.
Natural bio-identical progesterone (not the synthetic derivatives
that until recently have been heavily prescribed) is a very
safe hormonal treatment. Even if you don’t need it
because of the ipriflavone, it may still be worth taking.
In itself it helps to maintain bone density. Therefore it
can work quite well with ipriflavone to support the bones.
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