Mayo study finds dietary habits that may help prevent kidney stones

The results of a study conducted by Mayo Clinic suggest that diets with foods that are high in calcium and potassium may help prevent recurrent symptomatic kidney stones.1

“These dietary findings may have particular importance, because recommendations for preventing kidney stones have been based primarily on dietary factors associated with first-time, rather than recurrent stone formation,” Andrew Rule, MD, a Mayo Clinic nephrologist, said in a statement. “Patients may not be likely to adjust their diet to prevent an incidence of kidney stones, but they are more likely to do so if it can help prevent recurrence.”

There is about a 30% change of having another kidney stone within 5 years after experiencing a kidney stone once, according to the statement.

Dietary changes are often recommended to prevent recurrent symptomatic kidney stones, but there had been little of this research available on individuals who had 1 incident of kidney stones or recurrent incidents.

Investigators at Mayo Clinic designed the study to help understand the impact of dietary changes on kidney stones.

Dietary factors were based on a questionnaire administered to 411 individuals who had experienced first-time symptomatic kidney stones and a control group of 384 participants. All were seen at a Mayo Clinic location between 2009 and 2018.

The results, which were published in Mayo Clinic Proceedings, showed that lower dietary calcium and potassium, as well as lower intake of fluids, caffeine, and phytate, are associated with higher odds of experiencing a first-time symptomatic kidney stone.

Of those who had 1 kidney stone, 73 experienced recurrent stones within a median of 4.1 years of follow-up. Further analysis showed that lower levels of dietary calcium and potassium predicted recurrence.

Fluid intake of less than 3400 mL a day, which is about 9 12-oz glasses, is associated with first-time kidney stone formation. Daily fluid intake also includes intake from foods, such as fruits and vegetables.

Additionally, caffeine intake and phytate are also associated with first-time kidney stone formation.

Low caffeine and fluids intake can result in increased urine concentration and low urine volume, contributing to stone formation, while phytate is an antioxidant compound found in nuts, whole grains, and other foods that can lead to increased calcium absorption and urinary calcium excretion.

“Changing your diet to prevent kidney stones can be very difficult,” Rule said. “Thus, knowing the dietary factors that are most important for preventing kidney stone recurrence can help patients and providers know what to prioritize.”

Diets with a daily intake of 1200 milligrams of calcium may help prevent first-time and recurrent kidney stones, investigators said.

They also recommend higher potassium intake, but they do not recommend an intake level.

The key takeaway is that individuals should add more fruits and vegetables that are high in calcium and potassium to their diets, according to investigators.

Fruits high in potassium include bananas, cantaloups, grapefruits, and oranges, while vegetables high in potassium include cucumbers, mushrooms, peas, and potatoes.

Reference

1. Diets higher in calcium and potassium may help prevent recurrent symptomatic kidney stones, News release. Mayo Clinic study finds. EurekAlert. August 1, 2022. Accessed August 3, 2022. https://www.eurekalert.org/news-releases/960252