Kidney stones are bits of grit formed from minerals in the urine. They can be terribly painful, block urine flow, and damage kidneys. Diabetes is a major risk factor for kidney stones.
Stones start out small, like grains of sand. They may hurt, but they will pass by themselves. When they get larger than about 4 millimeters (about 0.2 inches) in diameter, they can get stuck in the ureters, the urine passageways. Then they can become agonizing, cause infection, and block urine in the kidney. This is a very serious complication.
Intense kidney stone pain is usually felt in the flank, the side of the mid- to lower back where the stone is. When pain is severe, it can cause vomiting leading to dehydration. These are serious problems for anyone, but especially for people with diabetes.
Kidney stones can form from several different minerals. The two main categories are calcium stones and uric acid stones. People with diabetes have higher rates of both, and much higher rates for the uric acid kind, because their urine tends to be more acidic. One study at the Mayo Clinic followed 3,500 patients for 20 years and concluded that those with diabetes developed 40% more uric acid kidney stones than those without diabetes
Scientists don’t know why diabetic urine is more acid. The American Society of Nephrology says insulin resistance has something to do with it. High levels of insulin in the blood are associated with acid urine. Bodies make buffers such as ammonium to neutralize the acid, and insulin resistance seems to lower the production of ammonium.
Other risk factors for stones include fatness, urinary tract infections, not drinking enough water, gastric bypass surgery, and high salt intake.
Most kidney stone prevention focuses on diet. The best supported results seem to come from the DASH (Dietary Approaches to Stop Hypertension) diet. DASH means high intake of fruits, vegetables, whole grains, and unsaturated fat. It restricts sodium, sugar, red meat, and processed meat.
In a study Web Editor Diane Fennell reported on here in 2009, researchers at Brigham and Women’s Hospital in Boston reviewed data on 242,000 health-care workers. Over 50 years of follow-up, those who closely followed DASH were between 40% and 45% less likely to develop kidney stones than those who did not. This decrease in risk was seen even after adjusting for factors such as age, body size, and fluid intake.
Beyond DASH, kidney stone diet advice can be confusing. According to the National Kidney Foundation, there is general agreement on these:
• Drink plenty of water. You should drink enough unsweetened fluid (water is best) to produce at least two quarts of urine per day. This is especially important if you are trying to lose weight, because weight loss releases acids, which can form stones.
• Reduce animal products as much as possible.
• Citrus fruits are good. That’s surprising. Isn’t acid the problem? Kidney stone specialist Dr. Allan Jhagroo of the University of Wisconsin explains that “Citrate in the urine may prevent the calcium from binding with other constituents that lead to stones. Also, some evidence suggests that citrate may prevent crystals that are already present from binding with each other, thus preventing them from getting bigger.” Dr. Jhagroo advises drinking minimally sweetened lemonade or limeade to get the benefits without raising blood sugars.
• Consume less sodium, less sugar, and less alcohol.
• Eat normal amounts of calcium. You don’t need to restrict it or supplement it.
• Avoid crash diets. The waste products can form stones.
• Apple cider vinegar and black cherry juice are advised by some herbalists, as are many other herbal approaches, which I cannot vouch for or against.
• Two kidney stone sufferers I talked with told me daily intake of chia seeds completely stopped their stones, which had put them in the hospital regularly for years.
Out of all these, by far the most important is the first one — stay hydrated! If the urine keeps moving, stones won’t have a chance to form or grow.
Although prevention is best, there are good treatments for kidney stones. They can be pulverized with shock waves, a treatment called ESWL (extracorporeal shock wave lithotripsy). They can be removed through a scope called a ureteroscope or by open surgery. Sometimes pain and vomiting are so severe that people are hospitalized. If you think you are having a kidney stone, see a doctor as soon as you can.