Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Plant Estrogens in Soy Do Not Increase Breast Cancer Risk

07.07.2004


Research in monkeys suggests that a diet high in the natural plant estrogens found in soy does not increase the risk of breast or uterine cancer in postmenopausal women.

“This is convincing evidence that at dietary levels, the estrogens found in soy do not stimulate cell growth and other markers for cancer risk,” said Charles E. Wood, D.V.M., lead researcher, from Wake Forest University Baptist Medical Center. “The findings should be especially interesting to women at high risk for breast cancer who take soy products.”

The research is reported in the current issue of The Journal of Clinical Endocrinology & Metabolism.



Wood said there has been much debate about whether high levels of dietary soy are safe for postmenopausal women. Soy products are sold as a natural alternative to traditional hormone therapy. The most common form of hormone therapy, estrogen plus a progestin, has been shown to increase risk of breast cancer.

Soy and some other plants contain estrogen-like compounds called isoflavones or phytoestrogens. These plant estrogens are thousands of times weaker than the estrogen produced by the body, but may be present in much higher concentrations in the blood. Evidence about their safety has been mixed. It is known that populations that typically consume diets high in soy have lower rates of breast cancer. On the other hand, some studies have shown that soy isoflavones can stimulate breast cancer cells grown in the laboratory.

“Evidence from observational studies in women indicates that soy intake may help prevent breast cancer,” said Wood. “But there has still been reluctance to conduct research studies in women because of concerns that isoflavones may stimulate breast cell growth and increase the risk of breast cancer.”

Wood and colleagues measured how a diet high in soy isofllavones affected markers for breast and uterine cancer risk in postmenopausal monkeys. The monkeys ate one of three diets for three years: soy that didn’t contain isoflavones, soy with the isoflavones intact, or soy without isoflavones, but with Premarin, or estrogen therapy, added.

The isoflavone group consumed the human equivalent of about 129 milligrams a day, more than most people would get in a soy-rich diet.

The researchers measured breast density, numbers of dividing breast and uterine cells, and levels of the estrogen produced by the body – all markers for cancer risk. Monkeys on the soy plus estrogen diet had increased levels of all markers, while monkeys that ate soy with isoflavones did not.

In fact, the monkeys eating soy with isoflavones had lower levels of the estrogen produced by the body. High levels of this estrogen are considered an important predictor of breast cancer risk in postmenopausal women.

“These findings suggest that high dietary levels of soy isoflavones do not increase markers for breast and uterine cancer risk in postmenopausal monkeys and may contribute to an estrogen profile associated with reduced breast cancer risk,” said the researchers.
Wood said it is important to note that the research addressed the effects of plant estrogens on normal breast tissue, and not in breast cancer.

“A big unanswered question is whether it is safe for breast cancer survivors to turn to soy,” he said.

Researchers are not certain how plant estrogens and the estrogen produced by the body, or given in pills, act together. One theory is that the plant estrogens bind to cells that have estrogen receptors, such as breast tissue, and block the effects of the other types of estrogen. Isoflavones may also help reduce the amount of active estrogen in the body.

To investigate these ideas, Wood and colleagues are currently looking at whether soy may block breast cell proliferation induced by estrogen therapy.

Other researchers involved the study included J. Mark Cline, Ph.D., D.V.M., Mary S. Anthony, Ph.D., Thomas C. Register, Ph.D., and Nancy D. Kock, Ph.D., D.V.M., all from Wake Forest Baptist.

The research was funded by grants from the National Institutes of Health.

| newswise
Further information:
http://www.wfubmc.edu

More articles from Health and Medicine:

nachricht Why might reading make myopic?
18.07.2018 | Universitätsklinikum Tübingen

nachricht Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>