Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dietary calcium is better than supplements at protecting bone health

21.06.2007
Women who get most of their daily calcium from food have healthier bones than women whose calcium comes mainly from supplemental tablets, say researchers at Washington University School of Medicine in St. Louis. Surprisingly, this is true even though the supplement takers have higher average calcium intake.

Adequate calcium is important to prevent osteoporosis, which affects an estimated 8 million American women and 2 million American men. Another 34 million Americans have low bone mass, placing them at increased risk for osteoporosis. Calcium consumption can help maintain bone density by preventing the body from stealing the calcium it needs from the bones.

The researchers' conclusions about calcium intake, published in the May issue of the American Journal of Clinical Nutrition, came from a study of 183 postmenopausal women. The researchers asked the women to meticulously detail their diet and their calcium supplement intake for a week. "We assumed that this sample represented each woman's typical diet," says senior author Reina Armamento-Villareal, M.D., assistant professor of medicine in the Division of Bone and Mineral Diseases and a bone specialist at Barnes-Jewish Hospital. "In addition to analyzing the volunteers' daily calcium intake, we tested bone mineral density and urinary concentrations of estrogen metabolites."

The researchers found that the women could be divided into three groups: one group, called the "supplement group," got at least 70 percent of their daily calcium from tablets or pills; another, the "diet group," got at least 70 percent of their calcium from dairy products and other foods; and a third, the "diet plus supplement group," consisted of those whose calcium-source percentages fell somewhere in between these ranges.

The "diet group" took in the least calcium, an average of 830 milligrams per day. Yet this group had higher bone density in their spines and hipbones than women in the "supplement group," who consumed about 1,030 milligrams per day. Women in the "diet plus supplement group" tended to have the highest bone mineral density as well as the highest calcium intake at 1,620 milligrams per day.

The hormone estrogen is known to maintain bone mineral density. But the standard form of estrogen is broken down or metabolized in the liver to other forms - some active and some inactive. Urinalysis showed that women in the "diet group" and the "diet plus supplement group" had a higher ratio of active to inactive estrogen metabolites than women in the "supplement group."

"This suggests that dietary calcium is associated with a shift in estrogen metabolism that favors production of active forms of estrogen," says Armamento-Villareal. "Although we're not yet certain what underlies this effect, it could be that nutrients other than calcium cause this shift. It's also known that dairy products, which are a major source of calcium, can contain active estrogenic compounds, and these can influence bone density and the amount of estrogenic metabolites in the urine."

Calcium supplements differ in how well their calcium can be absorbed, and this also could play a role in the study's findings, according to its authors. For example, calcium carbonate tablets need to be taken with a meal so that stomach acid can facilitate absorption, but calcium citrate tablets don't have this limitation. If the study participants taking calcium carbonate weren't conscientious about the timing of their supplements, they might not have received the highest benefit from them.

"Only about 35 percent of the calcium in most supplements ends up being absorbed by the body," Armamento-Villareal says. "Calcium from the diet is generally better absorbed, and this could be another reason that women who got a high percentage of calcium in their food had higher bone densities."

Although dairy foods are excellent sources of calcium, Armamento-Villareal suggests that individuals with dairy sensitivities could consume other calcium-rich food sources such as calcium-fortified orange juice. Dark green leafy vegetables also contain calcium, but it is not as readily absorbed as calcium from dairy sources.

Gwen Ericson | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Health and Medicine:

nachricht Laser activated gold pyramids could deliver drugs, DNA into cells without harm
24.03.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences

nachricht What does congenital Zika syndrome look like?
24.03.2017 | University of California - San Diego

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>