A research team from the University of Texas MD Anderson
Cancer Center has reported new evidence showing that phytoestrogens
are associated with a decrease in risk of lung cancer, in
the Journal of the American Medical Association (JAMA).
A complete copy of the original contribution can be found
online at the website for the Journal
of the American Medical Association
The research team examined the relationship
between dietary intake of phytoestrogens and risk of lung
cancer within an ongoing U.S. case-control study of 1,674
patients with lung cancer and 1,735 matched healthy controls.
All participants were interviewed frequently to determine
the dietary intake of 12 individual phytoestrogens for a
time period between July 1995 and October 2003.
The research team found the risk cancer
to be 46 per cent lower for those with the highest phytoestrogens
intake from all foods, or 21 per cent if they had a high
intake of phytosterols. Phytosterols are components added
to products to lower cholesterol.
The research team from the University of
Texas MD Anderson Cancer Center noted the limitations and
concerns regarding case-control studies of diet and cancer,
though feel their data adds to the growing epidemiologic
evidence that phytoestrogens are associated with a decrease
in risk of lung cancer.
Confirmation of these findings is still
required in large-scale, hypothesis-driven, prospective
Phytoestrogens are naturally occurring
plant compounds that are similar in some ways to estradiol,
the most potent naturally occurring estrogen. However, phytoestrogens
tend to have weaker effects than most estrogens, are not
stored in the body, and can be easily broken down and eliminated.
Observational studies have found a lower
prevalence of breast cancer, heart disease, and hip fracture
rates among people living in places like Southeast Asia,
where diets are typically high in phytoestrogens. As a result
of these studies, a great deal of interest has been generated
in the United States about the health benefits of phytoestrogens.
According to the Food and Drug Administration, the sale
of soy foods, a major source of phytoestrogens, has increased
dramatically in the past decade.
Dietary Sources of Phytoestrogens
Phytoestrogens consist of more than 20
compounds and can be found in more than 300 plants, such
as herbs, grains, and fruits. The three main classes of
dietary phytoestrogens are isoflavones, lignans, and coumestans:
daidzein, glycitein, and equol) are primarily found
in soy beans and soy products, chickpeas, and other legumes.
and enterodiol) are found in oilseeds (primarily flaxseed),
cereal bran, legumes, and alcohol (beer and bourbon).
can be found in alfalfa and clover.
Most food sources containing these compounds
typically include more than one class of phytoestrogens.
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