Kidney stones account for more than 650,000 emergency room treatments every year, according to the Urology Center of the Rockies. People develop different kinds of kidney stones because of hereditary, dietary and other factors. Apple juice can decrease the recurrence of brushite kidney stones. However, for people who have already had certain types of calcium kidney stones, consumption of apple juice increases the risk of developing more.
An estimated 2 to 3 percent of people develop kidney stones in their lifetimes, and about half of those who do develop more stones within a five-year period, notes the "Saudi Medical Journal." Rick factors include a family history of kidney stones, urinary tract infections, kidney disorders, Crohn's disease and metabolic disorders. Certain inherited conditions also heighten the risk of developing kidney stones, including renal tubular acidosis, hyperoxaluria and cystinuria. Specific surgical procedures, such as intestinal bypass or ostomy surgery, also increase the risk for kidney stones.
Kidneys remove toxins, waste and surplus water from your bloodstream, transforming these substances into urine, which it sends down tubes called ureters to your bladder for excretion. Your kidneys perform various other functions as well, including regulating:
1) the amount of water in your blood, body and skin.
2) minerals such as calcium, potassium, magnesium and phosphorus.
3) blood pressure.
Kidney stones occur when crystals in urine form into tiny masses. Normally, various factors inhibit the formation of these hard masses or keep the stones small enough that you can pass them without experiencing pain when you urinate. Calcium stones form when calcium in your urine combine with carbonate or oxalate derived from food you eat. Calcium also can combine with dietary phosphates to form brushite stones. Certain medical conditions, such as cystinuria, gout or urinary tract infections, contribute to the formation of cystine, stucite and uric acid stones.
Apple Juice and Stone Formation
Many fruits, including oranges, lemons, tangerines and limes, contain citrate, a compound that inhibits the development of calcium oxalate and carbonate stones. Citrus juices increase citrate levels and lower the acidity of urine, which decreases the risk of developing more stones. While apple juice contains a small amount of citrate, it does not appear to decrease the acidity of urine, nor decrease the risk of stone formation, according to a 1994 study reported in "American Journal of Epidemiology." In fact, the opposite is true. The risk of stone formation increased 35 percent for each 240 ml daily serving of apple juice. The March 1, 2010, edition of "The New York Times" reported that apple juice generally increases the risk of developing the most common types of recurrent kidney stones but decreases the risk of the relatively rare brushite kidney stones. To further complicate matters, brushite stones thrive in alkaline environments, in contrast to calcium oxalate and carbonate stones, which grow in acidic environments.