Every year, about 1 out of 1,000 adults in the United States is hospitalized because of stones in the urinary tract. Stones may form because the urine becomes too saturated with salts that can form stones or because the urine lacks the normal inhibitors of stone formation. About 80 percent of the stones are composed of calcium; the remainder, of various substances, including uric acid, cystine, and struvite. Struvite stones--a mixture of magnesium, ammonium, and phosphate--are also called infection stones, because they form only in infected urine. Stones vary in size from too small to be seen with the eye alone to 1 inch or more in diameter.

Natural Supplements for Kidney Stone prevention
There's little research in this area, but when I come across more information I will make sure to update this section. For now, I found one potential supplement, IP6, that may be helpful.

Subscribe to a FREE Supplement Research Update newsletter. Twice a month you will receive an email with reviews of several studies on various supplements and natural medicine topics, including bearberry, and their practical interpretation by Ray Sahelian, M.D.

IP5, phytic acid, and kidney stones
I received an email from a health reporter that asked, "I'm doing an article on kidney stones, and would love to include a quote from you. Specifically, I'm looking at the role of IP-6 in preventing kidney stone formation. How does it work? What's the recommended dosage? Any other supplements that may be helpful in preventing kidney stone formations?"
   IP-6, also known as phytate, is is a carbohydrate found in cereal grains, beans, brown rice, corn, sesame seeds, wheat bran, and other high fiber foods. Dietary phytate is helpful in inhibiting crystallization of calcium salts in the urine and consequently may reduce the risk of kidney stone development. Does ingesting an IP-6 supplement help reduce the risk for kidney stones? As of October 2007, I have not come across such human research. I am not aware of extensive, long term human studies that have specifically looked at the reduction of kidney stones with the use of natural supplements. However, magnesium is one option that shows promise.
   I did a search on Medline for IP6, phytate, and kidney stones, and came across these articles.

Phytate acts as an inhibitor in formation of renal calculi.
Front Biosci. 2007 Jan 1;12:2580-7. Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS), University of Balearic Islands, Palma of Mallorca, Spain.
The aim of this study was to assess the inhibitory action of phytate in formation of renal calculi. Hypertension (induced by nicotine) combined with hypercalcemia (induced by D vitamin) was used to induce calcification in renal tissue in male Wistar rats that were fed a purified phytate free diet. Phytate non-treated rats developed significant calcium deposits in kidneys and papillae, as well as in kidney tubules and vessels, whereas calcium deposits were absent in control and phytate treated rats. Fragments of hydroxyapatite (HAP) calculi exhibited the capacity to induce the growth of calcium salts on their surfaces. Presence of 1.5 mg/L of phytate in the synthetic urine inhibited the formation of calcium oxalate monohydrate on HAP renal calculi in normocalciuric conditions. The findings show that the action of phytate as a crystallization inhibitor takes place both in the intrapapillary tissue and urine.

Urinary phytate in calcium oxalate stone formers and healthy people--dietary effects on phytate excretion.
Scand J Urol Nephrol. 2000 Jun;34(3):162-4. Grases F, March JG, Prieto RM, Simonet BM, Costa-Bauzá A, García-Raja A, Conte A. Laboratory of Renal Lithiasis Research, University of Balearic Islands, Palma de Mallorca, Spain.
The phytate urinary levels in a group of active calcium oxalate stone formers were studied and compared with those found in healthy people. Urinary phytate was significantly lower for stone formers. If deficit of the capacity to inhibit crystallization of calcium salts is considered an important factor related to calcium stone formation, the excretion of low phytate amounts could be an important risk factor in the development of this type of renal calculi. The influence of dietary phytate on urinary excretion was also studied. Clearly maintenance of a phytate-free diet significantly decreased the urinary excretion of phytate (about 50% after 36 h). This demonstrated the importance of dietary phytate in maintaining adequate urinary levels to permit effective crystallization inhibition of calcium salts and consequently preventing renal stone development.

Phytate (IP6) is a powerful agent for preventing calcifications in biological fluids: usefulness in renal lithiasis treatment.
Anticancer Res. 1999 Sep-Oct;19(5A):3717-22. Laboratory of Investigation into Renal Lithiasis, Faculty of Sciences, University of Illes Balears, Palma de Mallorca, Spain.
The extraordinary capacity of phytate (myo-inositol hexaphosphate), a substance present in blood, urine, interstitial and intracellular fluids, to inhibit crystallization of calcium salts (oxalate and phosphate) is discussed. Its role in preventing calcium renal stone formation is specifically presented and discussed. "In vitro" and "in vivo" experiments, as well as clinical studies clearly demonstrated that phytate plays an important role as a crystallization inhibitor of calcium salts in biological fluids and becomes a clear alternative in the treatment of calcium oxalate renal lithiasis.

However, I could not find any human research where an IP-6 supplement was given for any length of time to determine if it reduced the risk for kidney stones.

Cause of Kidney Stones
Recent studies suggest that the incidence of kidney stones is increasing, both in the U.S. and worldwide, and data compiled by researchers at the Mayo Clinic in Rochester, Minnesota, suggest that diabetes may be a predisposing factor, particularly for kidney stones composed of uric acid. Overweight individuals are more likely to have more acidic urine, as measured by a lower urinary pH, along with an increased risk of uric acid kidney stones. Low fluid intake is another cause of kidney stone. Excessive caffeine intake may increase calcium excretion through the kidneys, increasing the likelihood of a stone.
   Men who work in the steel industry and are exposed to high temperatures are prone to develop kidney or urinary stones,. low levels of citrate in urine occurred more often in men in the hot-area group than those in the room-temperature group. Men in the hot-area group were also twice as likely to have low urine volumes. Both these conditions are involved in stone formation.

Treatment of kidney stones
Small stones that aren't causing symptoms, obstruction, or an infection usually don't need to be treated. Drinking plenty of fluids increases urine production and helps wash out some stones; once a stone is passed, no other immediate treatment is needed. The pain of renal colic may be relieved with narcotic analgesics.

Often, a stone in the renal pelvis or uppermost part of the ureter that's ½ inch or less in diameter can be broken up by ultrasound waves (extracorporeal shock wave lithotripsy). The pieces of stone are then passed in the urine. Sometimes, a stone is removed through a small incision in the skin (percutaneous nephrolithotomy), followed by ultrasound treatment. Small stones in the lower part of the ureter may be removed by an endoscope (a small, flexible tube) inserted into the urethra and through the bladder.

Uric acid stones are sometimes dissolved gradually by making the urine more alkaline (for example, with potassium citrate), but other types of stones can't be removed this way. Rarely, larger stones that are causing an obstruction may need to be removed surgically.

Types of kidney stones and various forms of treatment
Kidney stones come in a variety of forms: Calcium oxalate monohydrate papillary, calcium oxalate monohydrate unattached, calcium oxalate dihydrate, calcium oxalate dihydrate/hydroxyapatite, hydroxyapatite, struvite infectious, brushite, uric acid, calcium oxalate/uric acid and cystine.
   Measures to prevent the formation of new kidney stones vary, depending on the composition of the existing stones. These stones are analyzed, and urine levels of substances that can form stones are measured.
   Rarely, calcium stones result from another disorder, such as hyperparathyroidism, sarcoidosis, vitamin D toxicity, renal tubular acidosis, or cancer. In such cases, the underlying disorder is treated.
   For kidney stones that contain uric acid, a diet low in meat, fish, and poultry is recommended, because these foods increase the level of uric acid in the urine. Allopurinol may be given to reduce the production of uric acid. Potassium citrate may be given to make the urine alkaline, because uric acid stones form when urine acidity increases. Drinking large amounts of fluids also helps.
   For struvite stones--which indicate a urinary tract infection--antibiotics are given.

Kidney Stone Treatment Complications
Shock wave lithotripsy (SWL) of renal and proximal ureteral stones appears to increase the risk of hypertension and diabetes on long-term follow-up. SWL may promote hypertension by causing scarring in the kidneys and altering the secretion of blood pressure-modulating hormones. The link with diabetes may relate to damage inflicted upon the pancreas, they add.

Symptom of kidney stones
Pain, usually extreme, is the first symptom of a kidney stone. The pain may begin suddenly as a kidney stone moves in the urinary tract, causing irritation or blockage. Typically, the beginning of a kidney stone symptom starts when a person feels a sharp, cramping pain in the back and side around the area of the kidney, or in the lower abdomen. The pain may spread to the groin. Sometimes a kidney stone symptom could include nausea or even vomiting.
     When the stone is too large to pass easily, the pain continues as the muscles in the wall of the tiny ureter try to squeeze the stone along into the bladder. As a stone grows or moves, blood may be found in the urine. As the stone moves down the ureter closer to the bladder, a person may feel the need to urinate more often or feel a burning sensation during urination.
     Signs of a kidney stone include: extreme pain in the back or side that will not go away, blood in the urine, vomiting, and fever and chills.
     Q. Does every kidney stone symptom include pain? A. Most kidneys stones are very small and pass without causing a symptom.
     Q. Can a kidney stone symptom include constipation or diarrhea? A. Highly unlikely, the gastrointestinal symptom of kidney stone that occurs most commonly is nausea and sometimes vomiting.

Kidney Stone Research Update
If animal studies apply to humans, people taking the weight loss drug Xenical might have an increased likelihood of developing kidney stones, especially if they have a high intake of oxalate-containing foods. Researchers from the Federal University of Sao Paulo, Brazil, and the Karolinska Institute, Sweden, tested the effect of Xenical (known generically as orlistat) in 39 adult rats that were given a diet rich in oxalate alone or combined with fat (soy oil). With Xenical, oxalate levels in the urine were four to eight times higher than the baseline value, "elevating the risk of stone formation," the team reports in the August 2004 issue of Kidney International.

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.

Kidney cancer and tea drinking
Coffee and tea drinkers appear to have a slightly reduced risk of developing kidney cancer. The findings, based on an analysis of 13 previous studies, suggest that coffee and tea may be protective against kidney cancer, while milk, soda and juice seem to have no effect one way or the other. International Journal of Cancer, November 15, 2007.

Chronic kidney disease cause
In healthy men of normal weight, small increases in weight increase the risk of chronic kidney disease. Chronic kidney disease is on the list of conditions that are associated with weight gain, including diabetes and high blood pressure. Journal of the American Society of Nephrology, September 2008.

Supplements helpful for kidney disease
Acacia gum may be helpful in chronic kidney disease.