Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Studies find no evidence that estrogens in soy increase uterine cancer risk

03.11.2005


Studies in monkeys and women suggest that unlike traditional estrogen therapy, a diet high in the natural plant estrogens found in soy does not increase the risk of uterine cancer in postmenopausal women, according to Mark Cline, D.V.M., Ph.D., an associate professor of comparative medicine at Wake Forest University Baptist Medical Center.



"These findings give us some confidence that dietary soy doesn’t promote uterine cancer and, in fact, may offer a protective effect in some cases," said Cline, who summarized the research studies today in Chicago at the 6th International Symposium on the Role of Soy in Preventing and Treating Chronic Disease.

Cline said there has been much debate about whether high levels of dietary soy are safe for postmenopausal women. Soy products are sometimes sold as a natural alternative to traditional estrogen therapy, which does increase the risk of endometrial cancer. The formulation of hormone therapy designed to address that risk – a combination of estrogen and progesterone –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. 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 and uterine tissue, and block the effects of the estrogen pills or estrogen made by the body.

Evidence about the safety of soy isoflavones has been mixed. It is known that populations that typically consume diets high in soy have much lower rates of uterine cancer. On the other hand, some laboratory studies in animals have shown that soy isoflavones can stimulate the growth of uterine cells, which is a marker for cancer risk.

Last year, researchers from Italy reported that six women who took soy tablets for up to five years had an increased occurrence of endometrial hyperplasia, a condition in which the lining of the uterus grows too much and may progress to cancer. The study involved 375 women – half took the soy pills and half took an inactive placebo tablet.

"This observation from this study and its interpretation should be carefully considered," said Cline. "Both human observational studies and several short-term trials of soy isoflavones have not shown any proliferation-inducing effect of soy isoflavones on the uterus."

Cline said that preliminary results from a two-year study of women who consumed 58 milligrams of soy isoflavones a day show no relationship between the soy and endometrial proliferation, and that investigators at other institutions have made similar findings. Similarly, Cline said, monkeys who received soy isoflavones at dietary doses for the equivalent of 10 human years did not show increased risk of endometrial hyperplasia. The monkeys ate one of three diets: 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 numbers of dividing 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 a short-term study, researchers gave monkeys 10 times the levels of isoflavones normally consumed through diet and again found no effects on the uterus.

Cline said that the results of these studies apply to dietary soy – and not to the high levels of isoflavones found in soy pills. He also noted that the studies cannot completely rule out the potential for risk. However, he concludes that "the bulk of the experimental evidence points to a protective effect of soy consumption on endometrial cancer risk."

Karen Richardson | EurekAlert!
Further information:
http://www.wfubmc.edu

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>