• Calcium Oxalate Stones, Nephrolithiasis, Renal Calculi, Urinary Calculi, Urolithiasis
If you've ever passed a kidney stone, you do not want to repeat the experience! The sharp and irregular stones travel down the slender tube (ureter) leading from the kidney to the bladder, and from the bladder to the urethra, following the path by which urine exits the body. While tiny stones may pass unnoticed, a larger stone can induce some of the worst pain that humans experience.
Most kidney stones are composed of calcium and oxalic acid, substances present in the urine that can crystallize inside the kidneys. Although these chemicals occur in everyone's urine, our natural biochemistry is usually able to prevent them from crystallizing. However, sometimes these protective methods fail and a stone develops. This article focuses mainly on these calcium oxalate stones .
Less commonly, kidney stones may be made from calcium and phosphate, from another substance called struvite (usually the result of an infection) or, rarely, from uric acid or cystine.
It isn't known why some people develop kidney stones and others do not. However, once you've had a stone, you are fairly likely to develop another.
Low fluid intake greatly increases the risk of developing virtually all types of stones.
High intakes of sodium
Conventional treatment for kidney stones varies depending on symptoms as well as the location and chemical composition of the stones. For those who pass a stone spontaneously, the main treatments are painkillers and fluids. The chemical composition of passed stones can be analyzed to determine their cause. Other stones may be detected earlier, when they are still in the kidney. Treatment depends on their location and symptoms. Those causing problems may be treated with extracorporeal shock-wave lithotripsy , a technique that can break up these stones from outside the body, allowing them to pass more easily. Occasionally, however, surgery may be necessary.
"Silent" stones, or those causing no symptoms, are often treated with preventive measures alone. These methods include increasing fluids, modifying the diet, and taking drugs or supplements to alter the chemistry of the urine.
Principal Proposed Natural Treatments
Citrate, or citric acid, is an ordinary component of our diet, present in high amounts in citrus fruits. Citrate binds with calcium in the urine, thereby reducing the amount of calcium available to form calcium oxalate stones. It also prevents tiny calcium oxalate crystals from growing and massing together into larger stones. Finally, it makes the urine less acidic, which inhibits the development of both calcium oxalate and uric acid stones.
What Is the Scientific Evidence for Citrate?
One form of citrate supplement, potassium citrate, was approved by the FDA in 1985 for the prevention of two kinds of kidney stones: calcium stones (including calcium oxalate stones) and uric acid stones.
In a 3-year,
study of 57 people with a history of calcium stones and low urinary citrate levels, those given potassium citrate developed fewer kidney stones than they had previously. In comparison, the group given
Potassium-magnesium citrate was studied in a 3-year trial involving 64 participants with a history of calcium oxalate stones.
Citrate is available in the form of calcium citrate. Besides increasing citrate in the urine, this supplement has the advantage of being a readily absorbed form of calcium for those seeking to increase their calcium intake for other health reasons.
Some physicians have proposed drinking citrus juices as a means of increasing urinary citrate levels. Like potassium citrate, orange juice decreases urinary acidity and raises urinary citrate, but it also raises urinary oxalate, which might tend to work against its beneficial effects.
It was first thought that citrate supplements were only helpful against kidney stones in individuals who didn't excrete the normal amount of citrate in their urine.
The proper dosage of citrate depends on the chemical form and should be individualized under medical supervision.
Potassium citrate can irritate the gastrointestinal tract, causing upset stomach or bloating in 9% to 17% of people.
Supplements containing potassium have the potential to raise blood levels of potassium too high, primarily in people with impaired kidneys or those taking a
Citrate-induced reduction of urinary acidity can lead to decreased blood levels and effectiveness of numerous drugs, including
Other Proposed Natural Treatments
Two studies performed in Thailand hint that
A variety of herbs are often recommended for kidney stones, on the theory that they increase urine flow, which will help pass kidney stones. These include asparagus, birch leaf, bishop's weed fruit,
One study claimed to find trigger point injection (a form of treatment somewhat related to
According to some, but not all research, use of
supplements can slightly raise levels of oxalate in the urine,
Some evidence hints that excessive consumption of phosphorus in the form of soft drinks might increase kidney stone risk, but study results are contradictory, and if there is an effect, it appears to be small.
As noted above, regular consumption of grapefruit juice may significantly increase risk of stones.
36. Baggio B, Gambaro G, Marchini F, et al. Correction of erythrocyte abnormalities in idiopathic calcium-oxalate nephrolithiasis and reduction of urinary oxalate by oral glycosaminoglycans. Lancet . 1991;338:403-405.
41. Traxer O, Adams-Huet B, Pak CY, et al. Risk of calcium oxalate stone formation with ascorbic acid ingestion. Presented at: American Urological Association 2001 Annual Meeting; June 2-7, 2001; Anaheim, CA.
48. Curhan GC, Willett WC, Speizer FE, et al. Comparison of dietary calcium with supplemental calcium and other nutrients as factors affecting the risk for kidney stones in women. Ann Intern Med . 1997;126:497-504.
60. Allie-Hamdulay S, Rodgers AL. Prophylactic and therapeutic properties of a sodium citrate preparation in the management of calcium oxalate urolithiasis: randomized, placebo-controlled trial. Urol Res. 2005 May 4. [Epub ahead of print]
Last reviewed April 2009 by EBSCO CAM Review Board
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
Copyright © 2007 EBSCO Publishing All rights reserved.