How To Prevent Calcium Kidney Stones

By Shaoqing Zhou, MD

Anne Arundel Urology

. https://aaurology.com/

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How To Prevent Calcium Kidney Stones

The weather hit 100 degrees recently, and summer is upon us. Maryland is situated at the edge of the geographic “stone belt” that straddles across the southern United States, where there is increased incidence of kidney stone disease. Some people are fortunate enough to pass stones spontaneously without need for intervention, others may require surgeries of various degrees of invasiveness. This is a medical problem that is best avoided.

Over 70% of stones that we encounter are made of calcium, either calcium oxalate or calcium phosphate. Statistically, patients who have had one stone have about 50% chance of having another stone within 10 years. There are many strategies for lowering the risk of recurrence, here are common ones below

Hydration, hydration, hydration. The most important factor in stone prevention is to ensure you're well hydrated. Recommendation from the American Urological Association is to target 2.5 Liters of urine a day for stone formers. The old adage of drinking “eight cups of water” may be a good start, but in the summer time you may be outside gardening or out on the boat, and that amount may not be enough. 2.5L is hard to measure, but if we take into account that the adult bladder is about 400-500cc in capacity, then the rule of thumb is to fill the bladder 5-6 times a day.

Lowering calcium in urine. The relationship between the calcium we take in by mouth and the level of calcium in urine is not a simple one. It is recommended for patients who have calcium stones to take in a normal, but not excessive, amount of calcium. An increased level of sodium can indirectly increase the output of calcium, so lowering salt intake can improve your stone risk.

Decrease oxalate intake. Oxalate is a metabolite that comes from many things we eat and drink. It is found at high levels in spinach, nuts, chocolate, potatoes to name a few. There are many lists from reputable sources on google. One thing to note is that vitamin C supplement can be metabolized into oxalate, so check the back of the bottle of your vitamins and make sure this is necessary.

Despite these strategies, patients can continue to get kidney stones. It's at that time that we perform a more thorough workup including urine studies, blood work, and an objective measurement of urine output. Medication may be necessary depending on the findings on the workup.

Remember to stay hydrated.