Kidney stones are crystalline aggregates of waste material that form in urine when the concentration of crystal-forming substances, such as calcium oxalate and uric acid, exceed levels urine can dissolve. Successful stone passage depends on size and location; smaller stones and stones closer to the bladder are more likely to pass.
I perform a metabolic work-up on patients who have a history of recurrent kidney stones and on first-time patients with multiple stones. We then devise an algorithm including dietary and lifestyle changes, and medications if indicated.
To prevent calcium-oxalate stones, the most common form of kidney stones, keep water flowing. Half of fluid intake should be water. Avoid alcohol, a diuretic that increases urine output and may cause dehydration. Moderate calcium consumption, about 1,800 mg or less daily, is generally OK. Research has even shown that women with high calcium intakes are less likely to develop stones because dietary calcium binds with oxalates in the gastrointestinal tract so that oxalates can't be absorbed from the intestine and excreted by the kidney to form stones. But vitamin D increases calcium absorption and calcium supplements should be taken with meals.
Don’t consume excess amounts of oxalate-containing foods, including cranberries, spinach, rhubarb, raspberries, teas, colas, chocolate, and peanuts. Also, more than 1 gram vitamin C daily may increase oxalate. Calorie-rich foods increase the burden on the kidneys and also produce acidic urine. Insufficient fiber intake, less than 25 to 30 grams daily, also increases the risk of calcium-oxalate stones.
–Mark W. McClure, MD, FACS, Founder, Landmark Urology Care, Raleigh, North Carolina
Kidney stones can build up in the kidneys and get caught along the ureters, obstructing the path of urine exiting the body. Low urine volume, due to low fluid intake or dehydration, is the most common cause. Risk factors include metabolic disturbances (bowel, endocrine, and renal problems) that increase blood and urinary calcium oxalate levels; obesity or high blood pressure; and urinary tract infections. Most stones pass within one to four weeks, but some may last much longer with or without symptoms. Symptoms can include side and back pain, bloody or cloudy urination, painful urination, or nausea and vomiting. You may also experience chills and fever if an infection is present.
Reduce the chance of getting kidney stones by drinking eight 8-counce glasses of water daily (drink other fluids, such apple and cranberry juice, in moderation because they contain oxalate, which can increase the risk of calcium oxalate stones). A diet low in salt and very low in animal protein also can reduce your chance of developing certain types of kidney stones.
At-home treatments, notably fluid consumption, are usually sufficient for treating most kidney stones. Drink 8 to 16 8-ounce glasses of water per day to help the stone pass through the body. Also, get tap water tested to ensure it is not too soft or too hard. Hard water contains more calcium and less magnesium, which can worsen some types of stones. Soft water contains less calcium and more magnesium, which can worsen other types of stones.
–Sarah Amer, MS, RD, CDN, Nutrition Director, Millennium Fitness Club, Ramsey, New Jersey
Normally urine contains chemicals that prevent or inhibit kidney stones from forming; however, these inhibitors do not work for everyone. A person with a family history of kidney stones may be more likely to develop them. In addition to genetics, two things favor stone formation: dehydration and the combination of high urine uric acid and low urine pH.
The high incidence of calcium-containing stones is directly associated with dietary patterns: consuming too little fiber and too much highly refined carbohydrates, alcohol, animal protein, and fat. Dietary management is effective, inexpensive, and free of side effects. The specific treatment is determined by the type of stone and may include reducing urinary calcium; reducing purine (a natural substance that is metabolized into uric acid, a chemical that can create crystals when present in excess); avoiding high oxalate foods, such as black tea, coffee, cocoa, spinach, strawberries, cranberries, and nuts; eating more foods with a higher magnesium to calcium ratio such as grains; and eating more foods that are rich in vitamin K, such as leafy greens.
For prevention, I recommend increasing magnesium in the diet or by supplementation up to 400 to 800 mg daily. Magnesium is powerfully antispasmodic on smooth muscles likes those that line the ureter. Or try 250 mg of the botanical extract of Ammi visnaga three times daily to relax the ureter and allow the stone to pass. Hydrangea, Peucedanum, Leptotaenia, and Ruta graveolens work in the same way.
– Donna M. Merrill, RN, BSN, Sage Herbal Healing, LLC, Middletown, Delaware