Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Soy intake associated with reduced risk of breast cancer

05.04.2006
But meta-analysis does not uncover enough benefits to recommend use of soy supplements

Because some studies have suggested that soy contains chemicals that may help ward off breast cancer, increasing numbers of women are using soy supplements as a potential tumor preventive. But although a new meta-analysis of all available published data finds that while soy intake may be associated with a small reduction in the risk of breast cancer, there is no evidence to recommend the use of supplements, say scientists at Georgetown University Medical Center and Johns Hopkins School of Medicine. The research team will publish its findings in the April 5 issue of the Journal of the National Cancer Institute.

This conclusion may come as a surprise to many women who have come to depend on soy supplements to limit their risk of either developing breast cancer, or reducing breast cancer recurrence, says Robert Clarke, Ph.D., D.Sc., a professor at Georgetown’s Lombardi Comprehensive Cancer Center.

"Soy supplements contain high levels of isoflavones, such as genistein, that have estrogenic properties, while in soy foods isoflavones are just a part of the package. "Estrogens make the breast tumor cells grow," says co-author Leena Hilakivi-Clarke, PhD, a professor of Oncology whose laboratory at Lombardi has long studied the role of food-based estrogens in cancer prevention. "We found that soy food intake was associated with a reduced breast cancer risk. However, we have no idea what soy supplements might do," she adds

After research more than a decade ago showed that soy could play a role in decreasing LDL (known as the "bad" cholesterol) levels in humans, U.S. sales of soy-based food, drinks and supplements increased. But although U.S. sales of soy-based food and drinks were $3.9 billion in 2003, sales have slowed in recent years, according to the Soyfoods Association of North America, an association funded by the soy industry.

"Because soy foods and soy supplements are widely used, we conducted this first true meta-analysis to understand what role soy foods might have on breast cancer risk," said Clarke. "This objective examination of all of the studies tells us that currently, the data are not adequate to provide a clear answer to recommend soy foods to prevent breast cancer."

Although the study did not address the link between soy use and breast cancer recurrence, Clarke and Hilakivi-Clarke again cautioned against overuse of soy supplements, particularly by women at high risk for breast cancer or breast cancer survivors.

In the same way that estrogen-based hormone replacement therapy may be contraindicated for some women at high risk to develop breast cancer, soy isoflavone supplementation may not be a good idea for these women either, the researchers said. Co-author Bruce Trock, PhD, of the Johns Hopkins School of Medicine added, "High-dose soy or isoflavone supplements have biological effects that are different from normal soy foods, and no one has studied the effect of long-term consumption of such supplements."

"Soy foods like tofu and soy milk are readily available now if women want to add them to their diet," Trock said.

Because soy has recently become a widely used food additive in the United States, many Americans get some soy that they are not aware of, said Hilakivi-Clarke. "Our data suggests that women do not need to consume very much soy to possibly benefit from it. Higher soy intake does not provide additional risk reduction," she said.

To conduct the meta-analysis, Clarke, Hilakivi-Clarke, and Trock looked at 18 epidemiologic studies published between 1978 and 2004 that examined the association between soy intake and breast cancer risk. Some of these studies were based on the hypothesis that Asian women have reduced incidence of breast cancer, compared to American women, because they have traditionally eaten a diet rich in soy foods, such as tofu. In some studies, soy foods were just one of the food items studied in connection to breast cancer risk.

The results of the meta-analysis indicated a small association between soy intake and a reduced risk of breast cancer. Risk appeared to be reduced to a somewhat greater extent in premenopausal than postmenopausal women, however only 10 of 18 studies evaluated the effect separately by menopausal status. Studies that did not address menopausal status provided less evidence for the risk reducing effect.

While the data were too inconsistent to recommend soy as a breast cancer preventive, the authors say there is no evidence to suggest that consumption of soy foods in amounts consistent with an Asian diet is detrimental to breast health. Any overall health benefits offered by traditional soy foods in the diet, modest though they may be, likely outweigh any risks for the population as a whole, the authors said.

Liz McDonald | EurekAlert!
Further information:
http://lombardi.georgetown.edu
http://www.georgetown.edu

More articles from Life Sciences:

nachricht Flow of cerebrospinal fluid regulates neural stem cell division
22.05.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Chemists at FAU successfully demonstrate imine hydrogenation with inexpensive main group metal
22.05.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>