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 have come across preliminary research that certain supplements may be helpful. These include aloe vera, probiotics, and IP6.

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.
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. 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. 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.

Aloe vera
Fresh Aloe vera gel (100 g) contains 96 mg of citrate and 158 mg of tartrate. This is mid-range for Thai fruits. Changes in chemical compositions of urine after aloe consumption shows its potential for preventing kidney stone formation among adults. J Med Assoc Thai. 2006 Aug. Effect of aloe (Aloe vera Linn.) on healthy adult volunteers: changes in urinary composition. Department of Pediatrics, Faculty of Medicine, Khon Kaen University, Thailand.

Probiotics
Patients with inflammatory bowel disease have a 10- to 100-fold increased risk of nephrolithiasis, with enteric hyperoxaluria being the major risk factor for these and other patients with fat malabsorptive states. Endogenous components of the intestinal microflora can potentially limit dietary oxalate absorption. Manipulation of gastrointestinal (GI) flora can influence urinary oxalate excretion to reduce urinary supersaturation levels. These changes could have a salutary effect on stone formation rates. Further studies will be needed to establish the optimal dosing regimen. Kidney Int. 2005 Sep. Use of a probiotic to decrease enteric hyperoxaluria. Lieske JC, Goldfarb DS, De Simone C, Regnier C. Division of Nephrology and Hypertension, Mayo Clinic, Mayo Hyperoxaluria Center, and Mayo Complementary and Integrative Medicine Program, Rochester, Minnesota 55905, USA.

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.
   Kidney stones are on the rise in children, due in part to a poor diet, physical inactivity, and rising rates of childhood obesity.
   High dose turmeric spice ingestion may increase the risk for oxalate 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.

Drinking diet soda?
Certain diet sodas may have the potential to prevent the most common type of kidney stone. Researchers found that the diet versions of several popular citrus-flavored sodas -- like 7Up, Sunkist and Sprite -- contained relatively high amounts of a compound called citrate. Citrate, in turn, is known to inhibit the formation of calcium oxalate stones, the most common form of kidney stone. One reason that certain people are prone to being "stone-formers" is that their urine contains relatively little citrate. Dr. Brian H. Eisner, a urologist at Massachusetts General Hospital in Boston  says potassium citrate supplements have long been a common treatment for preventing calcium oxalate stones, as well as another type of stone called uric acid stones, in people who are prone to them.  The goal of the current study by Dr. Brian H. Eisner was to see whether any commercially available drinks had a similar citrate content. The study found citrus-based diet sodas -- including 7Up, Sunkist Orange, Sprite, Fresca and Canada Dry ginger ale -- had somewhat higher citrate levels than homemade lemonade. Dark colas, on the other hand, had little to no citrate. Whether citrus-flavored diet sodas can actually help prevent kidney stones is still unknown. Journal of Urology, online April 19, 2010.

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. The pain may begin suddenly as a 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.
     Most kidneys stones are very small and pass without causing a symptom.
     Can a kidney stone symptom include constipation or diarrhea? Highly unlikely, the gastrointestinal symptom of kidney stone that occurs most commonly is nausea and sometimes vomiting.

Research studies
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.

Supplements and herbs for urinary tract infections
Herbs used in urinary tract infections or bladder infections including cranberry
Bearberry herb
Cranberry herb is available as a supplement in capsule form.