Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers find calcium intake contributing factor in formation of kidney stones

29.12.2004


Individuals with either calcium oxalate or calcium phosphate kidney stones should not take extra calcium on their own as suggested by previous research, but should check with their doctors to determine the dietary guidelines that work best for them, researchers at UT Southwestern Medical Center at Dallas have found.



Articles published by UT Southwestern researchers in the November issue of Kidney International and the December issue of the Journal of Urology showed that urinary calcium - the amount of calcium in a person’s urine - is an important contributing factor in the formation of both types of kidney stones. Earlier studies had downplayed the significance of calcium when compared to the levels of oxalate in urine, and even encouraged kidney stone patients to increase their dietary intake of calcium.

"We often see patients who tell us they have been advised to take more calcium; however, that could be a dangerous recommendation for some individuals," said Dr. Margaret Pearle, an author of the first study, professor of urology and internal medicine at UT Southwestern. "While we want to be cautious in asking anyone to restrict calcium intake because of the risk of bone disease, we also realize that urinary calcium has about the same influence as urinary oxalate in calcium oxalate stone formation, and we may want to recommend calcium restriction in patients who have moderately to severely elevated intestinal calcium absorption and urinary calcium levels," she said.


The same is true for patients with calcium phosphate stones, said Beverley Adams-Huet, an author of both studies, a faculty associate in internal medicine and a biostatistician in UT Southwestern’s General Clinical Research Center (GCRC). "The second study reaches a similar conclusion, which is that the level of urinary calcium has an important influence in the formation of calcium phosphate stones," she said. "This offers supportive evidence that people with calcium phosphate stones may need to carefully monitor their calcium dietary intake."

An estimated 10 percent of Americans will have a kidney stone some time in their lives, with men typically affected more frequently than women.

Kidney stones are solid deposits that form in the kidneys from substances excreted in urine. When waste materials in urine do not dissolve completely, microscopic particles begin to form and over time grow into kidney stones. The most common type of kidney stone contains calcium in combination with either oxalate or phosphate, with calcium oxalate stones accounting for about 60 percent and calcium phosphate about 20 percent of kidney stones.

Both studies looked at data from patients in UT Southwestern’s kidney stone registry, a computer database of medical information gleaned from more than 2,200 kidney stone patients evaluated at the GCRC during the past 27 years. The first study looked at data from 667 patients with predominantly calcium oxalate stones; the second considered data from 133 patients with predominantly calcium phosphate stones.

Calcium was not regarded as important as oxalate in kidney stone formation in earlier studies because a different "stability constant," or mathematical formula, was used to calculate urinary saturation of calcium oxalate, with results showing that less attention should be focused on calcium. Researchers at UT Southwestern, however, used a newer, lower stability constant, today regarded as the "gold standard" in the industry, yielding data that pointed to calcium’s more essential role.

Dr. Charles Y.C. Pak, lead author on both studies and former director of the Charles and Jane Pak Center for Mineral Metabolism and Clinical Research at UT Southwestern, urged patients to seek their physician’s advice before deciding whether to limit or increase calcium in their diets.

"For the patient, the message of these studies is that the recommendation for calcium intake cannot be generalized since the effect of calcium intake on stone formation depends on the type of stone, oxalate intake, presence of stones and the efficiency of calcium absorption from the bowel," said Dr. Pak. "Our future challenge is to understand various factors that modify the effect of calcium restriction on urinary calcium and stone-forming propensity, and to determine how best to use diet and drugs to control hypercalciuria (high urinary calcium) and stone formation."

Also participating in the first study were Dr. Orson W. Moe, director of the Charles and Jane Pak Center for Mineral Metabolism and Clinical Research; Roy D. Peterson, nurse administrator; and John R. Poindexter, software systems supervisor.

Both studies were supported by grants from the National Institutes of Health.

Donna Steph Hansard | EurekAlert!
Further information:
http://www.utsouthwestern.edu

More articles from Health and Medicine:

nachricht Penn vet research identifies new target for taming Ebola
12.01.2017 | University of Pennsylvania

nachricht The strange double life of Dab2
10.01.2017 | University of Miami Miller School of Medicine

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: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Satellite-based Laser Measurement Technology against Climate Change

17.01.2017 | Machine Engineering

Studying fundamental particles in materials

17.01.2017 | Physics and Astronomy

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>