Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study: Isoflavone-enriched soy proteins fail to increase bone mineral density in young women

24.10.2002


Soy protein enriched with isoflavones appears to have no effect on bone mineral content and bone mineral density in young women, according to a new study. Researchers say the finding will disappoint nutritionists hoping to document benefits from diets containing the nutrients, not to mention the soy industry.

A report on the study, conducted at the University of North Carolina at Chapel Hill, appears in the current (October) issue of the Journal of the American College of Nutrition. Isoflavones are chemicals made by plants, possibly to protect them against oxidation and organisms that might attack them, and soy beans are an especially good source.

"We had seen earlier reports that isoflavones had beneficial effects on the bones of women undergoing menopause or who already were postmenopausal," said Dr. John J.B. Anderson, professor of nutrition at the UNC schools of public health and medicine. "We felt that if this were true for older women, it might also be true for healthy young women and could help protect their bones over their lifetimes."



The study involved 28 young women in their early 20s. One group of 15 volunteers took soy protein supplements enriched with isoflavones for a year. The second group consumed an isoflavone-deficient soy protein diet, along with other foods over the same period. No one knew until the study ended who was in which group.

Researchers assessed the bone mineral content and density of each subject using dual-energy X-ray absorptiometric measurements at the beginning of the project, after six months and after a year, Anderson said. In other words, they scanned the young women’s whole bodies, spines and upper thighbones to determine how dense their bones were and if those measurements changed over time. The team also controlled for each woman’s body mass index -- a measure of how heavy she was for her height – along with her physical activity level and diet.

"We found no changes in bone mineral densities and contents after 12 months in either the isoflavone-treated group or the isoflavone deficient group," he said. "Other variables also remained essentially constant over the year, including normal menstrual patterns in both groups."

Isoflavones such as genistein are structurally similar to human estrogens and for that reason have some estrogen-like properties, Anderson said. Scientists and drug companies have become increasingly interested in them over the past few years since the naturally occurring chemicals seem to produce positive effects in bone without the negative impact, such as cancer, that estrogens are believed to have on reproductive organs in some women. The value of estrogens remains in dispute.

"We were surprised that we saw zero effect," he said. "We think we found nothing because our young women were menstruating normally and therefore had normal estrogen levels. The natural estrogen levels may simply have overwhelmed any possible effect of the isoflavones."

Repeating the small but intensive UNC study to confirm or refute the results should help clarify if the new findings are valid, the scientist said.

"A lot of women are taking these plant products because they are afraid of taking estrogens due to the possible cancer risks," Anderson said. "We need more data to be able to say that, yes, there’s a benefit, or no there’s not. Right now, we have a lot more questions than answers, but at least we don’t think soy isoflavones are harmful in any way."

Co-authors of the report are graduate Xiaowei Chen, who will receive his doctorate in nutrition in December; Dr. Agna Boass, former research associate; Dr. Michael Symons, professor of biostatistics; Dr. Martin Kohlmeier, research professor of nutrition; and Dr. Jordan B. Renner, associate professor of radiology, all at UNC. Dr. Sanford C. Garner of TPMC Inc., a Research Triangle Park-based research company, also collaborated in the study.


Support for the work came from the United Soybean Board of Chesterfield, Mo., and Protein Technologies International Inc. of St. Louis. The UNC researchers used the same soy isoflavones previously used in two studies at the University of Illinois and Iowa State University reporting beneficial effects of isoflavones in menopausal and post-menopausal women.

Note: Anderson can be reached at 919-966-7220 or jjb_anderson@unc.edu

David Williamson | EurekAlert!
Further information:
http://www.unc.edu/

More articles from Studies and Analyses:

nachricht Statistical method developed at TU Dresden allows the detection of higher order dependencies
07.02.2020 | Technische Universität Dresden

nachricht Novel study underscores microbial individuality
13.12.2019 | Bigelow Laboratory for Ocean Sciences

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: High-pressure scientists in Bayreuth discover promising material for information technology

Researchers at the University of Bayreuth have discovered an unusual material: When cooled down to two degrees Celsius, its crystal structure and electronic properties change abruptly and significantly. In this new state, the distances between iron atoms can be tailored with the help of light beams. This opens up intriguing possibilities for application in the field of information technology. The scientists have presented their discovery in the journal "Angewandte Chemie - International Edition". The new findings are the result of close cooperation with partnering facilities in Augsburg, Dresden, Hamburg, and Moscow.

The material is an unusual form of iron oxide with the formula Fe₅O₆. The researchers produced it at a pressure of 15 gigapascals in a high-pressure laboratory...

Im Focus: From China to the South Pole: Joining forces to solve the neutrino mass puzzle

Study by Mainz physicists indicates that the next generation of neutrino experiments may well find the answer to one of the most pressing issues in neutrino physics

Among the most exciting challenges in modern physics is the identification of the neutrino mass ordering. Physicists from the Cluster of Excellence PRISMA+ at...

Im Focus: Therapies without drugs

Fraunhofer researchers are investigating the potential of microimplants to stimulate nerve cells and treat chronic conditions like asthma, diabetes, or Parkinson’s disease. Find out what makes this form of treatment so appealing and which challenges the researchers still have to master.

A study by the Robert Koch Institute has found that one in four women will suffer from weak bladders at some point in their lives. Treatments of this condition...

Im Focus: A step towards controlling spin-dependent petahertz electronics by material defects

The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.

Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...

Im Focus: Freiburg researcher investigate the origins of surface texture

Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.

Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

70th Lindau Nobel Laureate Meeting: Around 70 Laureates set to meet with young scientists from approx. 100 countries

12.02.2020 | Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

 
Latest News

Scientists 'film' a quantum measurement

26.02.2020 | Physics and Astronomy

Melting properties determine the biological functions of the cuticular hydrocarbon layer of ants

26.02.2020 | Interdisciplinary Research

Lights, camera, action... the super-fast world of droplet dynamics

26.02.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>