What Can Cause Kidney Stones?

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Kidney stones are hard deposits of minerals and salts found in urine that stick together to form a stone. Several factors can cause kidney stones to form. The actual cause may never be determined unless you pass a stone, collect it, and give it to your doctor for analysis. By doing so, you also may be able to find out how to prevent kidney stones in the future. Learn more about common causes of kidney stones and how to reduce your risk of developing a kidney stone.

Common Kidney Stone Causes

Without knowing the type of kidney stone, it’s hard to determine exactly what causes kidney stones, but there are some common causes:

  • An excessive amount of calcium, oxalate, cystine and/or uric acid in the urine
  • A lower urine pH level
  • A deficiency of stone-inhibiting elements that prevent stones from forming
  • Acid urine or chronic urinary infections

Types of kidney stones

There are four common types of kidney stones:

  • Calcium: Calcium kidney stones are the most common type of kidney stones. These stones actually are not the result of ingesting too much calcium. Instead, it’s the result of too much calcium oxalate, which is made daily by your liver and is also found in certain foods.
  • Uric acid: A waste product of chemical reactions in the body, uric acid will begin to form crystals when mixed with urine. “Having acidic urine may be due to obesity, type 2 diabetes, gout, or a diet too high in animal protein,” says S. Adam Ramin, M.D., medical director of Urology Cancer Specialists in Los Angeles.
  • Struvite: Made of calcium ammonium, struvite kidney stones typically form as a result of an infection.
  • Cystine: Cystine kidney stones are caused by a hereditary disorder wherein the kidneys do not reabsorb cysteine, an amino acid, from the urine.

Reducing Your Risk of Kidney Stones

Although not entirely preventable, there are certain things you can do to reduce your risk of developing a kidney stone. Kidney stone prevention tips include:

  • Stay hydrated. “If you are prone to stones, having at least two to three liters of urine output per day is helpful,” says Michael D. Trotter, M.D., owner of Midtown Urology Associates in Austin, Texas.
  • Maintain a diet low in animal protein, carbohydrates and salt. “As you notice, this diet is really a heart-healthy diet,” says Robert C. Greenwell Jr., M.D., chief of nephrology at Mercy Medical Center in Baltimore. Limiting vitamin D milk intake as well as nuts and chocolate, which have a high oxalate content, also can help prevent kidney stones.
  • Maintain a healthy weight. Being overweight can cause your body to produce more uric acid and oxalate—both are contributing factors of kidney stones.
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 May 12
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