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 Scientists track ovarian cancers to site of origin: Fallopian tubes
23.10.2017 | Johns Hopkins Medicine

nachricht Researchers release the brakes on the immune system
18.10.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Symposium on Driving Simulation

23.10.2017 | Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

 
Latest News

Introduction of a novel system for in vitro analyses of zebrafish oligodendrocyte progenitor cells

23.10.2017 | Life Sciences

Did you know how many parts of your car require infrared heat?

23.10.2017 | Automotive Engineering

3rd Symposium on Driving Simulation

23.10.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>