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 Malaria Already Endemic in the Mediterranean by the Roman Period
27.07.2017 | Universität Zürich

nachricht Serious children’s infections also spreading in Switzerland
26.07.2017 | Universitätsspital Bern

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: Abrupt motion sharpens x-ray pulses

Spectrally narrow x-ray pulses may be “sharpened” by purely mechanical means. This sounds surprisingly, but a team of theoretical and experimental physicists developed and realized such a method. It is based on fast motions, precisely synchronized with the pulses, of a target interacting with the x-ray light. Thereby, photons are redistributed within the x-ray pulse to the desired spectral region.

A team of theoretical physicists from the MPI for Nuclear Physics (MPIK) in Heidelberg has developed a novel method to intensify the spectrally broad x-ray...

Im Focus: Physicists Design Ultrafocused Pulses

Physicists working with researcher Oriol Romero-Isart devised a new simple scheme to theoretically generate arbitrarily short and focused electromagnetic fields. This new tool could be used for precise sensing and in microscopy.

Microwaves, heat radiation, light and X-radiation are examples for electromagnetic waves. Many applications require to focus the electromagnetic fields to...

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

Oestrogen regulates pathological changes of bones via bone lining cells

28.07.2017 | Life Sciences

Satellite data for agriculture

28.07.2017 | Information Technology

Abrupt motion sharpens x-ray pulses

28.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>