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 Organ-on-a-chip mimics heart's biomechanical properties
23.02.2017 | Vanderbilt University

nachricht Researchers identify cause of hereditary skeletal muscle disorder
22.02.2017 | Klinikum der Universität München

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>