Diets with more calcium and potassium may help prevent recurring symptomatic kidney stones
Kidney stones can not only cause excruciating pain, but they have also been linked to chronic kidney disease, osteoporosis, and cardiovascular disease. Once you’ve had a kidney stone, you have a 30% chance of getting another kidney stone within five years.
Most often, doctors prescribe dietary changes to prevent recurring symptomatic kidney stones. Unfortunately, little research is available regarding dietary changes for those who have one incident of kidney stone formation versus those who have recurrent incidents.
A kidney stone is a firm, pebble-like piece of material that can form in one or both kidneys when your urine is high in certain minerals.
Therefore, Mayo Clinic researchers designed a prospective study to examine the impact of dietary changes. According to their results, fortifying diets with foods high in calcium and potassium can prevent recurrent symptomatic kidney stones.
411 patients who had experienced symptomatic kidney stones for the first time and a control group of 384 people participated in the study. Dietary factors were based on a questionnaire administered to the participants, all of whom were seen at the Mayo Clinic in Rochester and Mayo Clinic in Florida between 2009 and 2018. The findings, published today (August 1) in Procedures at the Mayo Clinicshow that lower dietary calcium and potassium, as well as lower intakes of fluids, caffeine and phytate, are associated with a greater chance of experiencing a first symptomatic kidney stone.
Of the first-time stone formation patients, 73 experienced recurrent stones within a median of 4.1 years of follow-up. Further analysis revealed that lower levels of dietary calcium and potassium predicted a recurrence.
“These nutritional findings may be of particular interest because recommendations for preventing kidney stones are based primarily on dietary factors associated with first time rather than recurrent stone formation,” says Andrew Rule, MD, a Mayo Clinic nephrologist and senior author. of the research. “Patients probably won’t change their diet to prevent the occurrence of kidney stones, but they are more likely to do so if it can help prevent recurrence.”
Fluid intake of less than 3,400 milliliters a day, or about nine 12-ounce glasses, is associated with first stone formation, along with caffeine intake and phytate, the study finds. Daily fluid intake includes intake of foods such as fruits and vegetables.
Drink plenty of water if you have kidney stones, unless otherwise directed by a health care professional.
Low intake of fluids and caffeine can result in low urine volume and increased urine concentration, contributing to the formation of stones. Phytate is an antioxidant found in whole grains, nuts 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,” says Dr. rule. “So knowing the dietary factors most important to prevent kidney stone recurrence can help patients and caregivers know what to prioritize.”
Low dietary calcium and potassium levels were a more important predictor than fluid intake of recurrent kidney stone formation, says Api Chewcharat, MD, the paper’s lead author and a postdoctoral researcher at Mayo Clinic at the time of the study. “This isn’t to say that high fluid intake isn’t important. We just haven’t found any benefits of increasing fluid intake in those patients with a history of kidney stone formation.”
The study concludes that diets with a daily intake of 1,200 milligrams of calcium can help prevent the first and recurrent kidney stones. This daily intake is in line with the daily recommended diet of the Ministry of Agriculture.
While a higher potassium intake is also recommended, the USDA does not recommend daily potassium intake. The study also does not recommend an intake level.
dr. Chewcharat says the takeaway is for patients to add more fruits and vegetables high in calcium and potassium to their diets. Fruits high in potassium include bananas, oranges, grapefruits, melons, honeydew melons and apricots. Vegetables include potatoes, mushrooms, peas, cucumbers and zucchini.
Reference: “Dietary Risk Factors for Occasional and Recurrent Symptomatic Kidney Stones” Aug 1, 2022, Procedures at the Mayo Clinic.
Co-authors with Drs. Rule and Chewcharat are Charat Thongprayoon, MD; Lisa Vaughan; Ramila Mehta; Phillip Schulte, Ph.D.; Helen O’Connor; and John Lieske, MD — all of Mayo Clinic — and Erin Taylor, MD, of VA Maine Healthcare System. dr. Schulte reports OxThera Inc. personal fees. outside of work on this study. dr. Lieske reports grants and/or other reimbursements from pharmaceutical and related companies mentioned in the article – all outside of this study and all paid to Mayo Clinic. The other authors report no competing interests.