Eating more of this may prevent kidney stones

If you are prone to kidney stones, you may want to stock up on bananas and yogurt.

A small study conducted at the Mayo Clinic published in Science Daily found that a diet enriched with foods high in calcium and potassium may prevent a recurrence of the painful condition.

Researchers administered a questionnaire to 411 patients with first-time symptomatic kidney stones and results showed that 73 experienced recurrent stones within 4.1 years of follow-up. The study also showed lower dietary calcium and potassium, lower intake of fluids, caffeine and phytate were associated with higher chances of a first-time symptomatic stone.

Researchers concluded that diets with a daily intake of 1,200 milligrams of calcium may help prevent recurrent kidney stones in addition to first-time stones.

“This study is talking about the most common type of kidney stones, which are calcium oxalate stones,” said John J. Homa, DO, FACOS, a urologist with Urology Associates of Cape Cod. “Other types of stones include uric acid, cystine stones, and struvite stones.”

Historically, people who had a calcium oxalate stone were told to reduce their calcium intake, he said. That concept is outdated, and the current recommendation is to maintain a good dietary intake of calcium and reduce your intake of oxalate. The calcium binds with oxalate in the gut and reduces the amount of oxalate that ends up in your urine to precipitate and form stones.

“We give patients information on low oxalate diets,” said Dr. Homa. “Unfortunately, foods high in oxalate are many of the healthier foods such as green leafy vegetables including kale, spinach, blueberries, blackberries and nuts.”

“Statistically, the average person who has one stone may have a 50% chance over 10 years of having another stone,” said Dr. Homa.

Preventing Stones

Kidney stones are mineral deposits that form crystals in your urine, according to Dr. Homa. “This can happen when your urine is concentrated. If you can dilute your urine with more water, then precipitation of crystals is less likely to occur. The hallmark of stone prevention is drinking a lot of fluids.”

The amount to drink is usually based on the urine output, according to Dr. Homa. In some cases, a 24-hour urine collection can be done to measure urine output. You should be making about 2-2 ½ liters of urine per day, which is about 2-2 ½ quarts or 64-80 fluid ounces. That correlates to drinking a little more than that.

When a stone forms in the kidney, it can remain small, or grow larger according to the Urology Care Foundation. Some will pass from the kidney down the ureter into the bladder and pass through the urine. Larger ones may get lodged in the ureter causing the urine to back up into the kidney and cause pain.

Symptoms and Treatment

The most common symptom of kidney stones is flank pain that will often radiate around to the front into the groin area and some patients will have blood in their urine, said Dr. Homa.

Removal depends on the size. Stones less than 4-5 mm have a good chance of passing and stones larger than that often won’t pass, according to Dr. Homa.

“Kidney stone surgery is one of the most common procedures we do at Cape Cod Hospital. We do them almost daily,” he said.

Many may be aware of the old-fashioned sound wave lithotripsy to fragment stones so they could be removed, said Dr. Homa. This type of lithotripsy has been declining in use. In the past several years, camera technology and laser fiber technology and laser lithotripsy has resulted in a higher success rate and the results are more definitive than sound waves. These are most of the procedures we do now. It is minimally invasive, and patients go home the same day.