Diets high in calcium and potassium may help prevent recurring symptomatic kidney stones
Not only can kidney stones cause excruciating pain, but they are also associated with chronic kidney disease, osteoporosis, and cardiovascular disease. If you have ever had a kidney stone, you have a 30% chance of having another kidney stone within five years.
Typically, doctors prescribe dietary changes to prevent recurring symptomatic kidney stones. Unfortunately, there is little research available regarding dietary changes for those with one incident of kidney stone formation compared to those with recurring incidents.
A kidney stone is a pebble-like piece of solid material that can form in one or both of your kidneys when your urine contains high levels of certain minerals.
Therefore, Mayo Clinic researchers designed a prospective study to investigate the impact of dietary changes. According to their findings, enriching diets with foods rich in calcium and potassium can prevent recurring symptomatic kidney stones.
411 patients who had had symptomatic kidney stones for the first time and a control group of 384 people participated in the study. The dietary factors were based on a questionnaire administered to participants, all of whom were seen at Mayo Clinic in Rochester and Mayo Clinic in Florida between 2009 and 2018. The results, which will be published today (August 1) in Mayo Clinic Proceedingsshow that low dietary calcium and potassium, as well as low fluid, caffeine and phytate intake, are associated with a higher likelihood of having a first symptomatic kidney stone.
Of the patients who had stone formation for the first time, 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 recurrence.
“These dietary findings may have particular significance because recommendations for preventing kidney stones have been based primarily on dietary factors associated with initial rather than recurrent stone formation,” says Andrew Rule, MD, Mayo Clinic nephrologist and author. principal of the study. “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.”
Fluid intake of less than 3,400 milliliters a day, or about nine 12-ounce glasses, is associated with the first formation of stones, as well as caffeine and phytate intake, according to the study. 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 healthcare professional.
Low fluid and caffeine intake can cause low urine volume and increased urine concentration, contributing to stone formation. Phytate is an antioxidant compound found in whole grains, nuts, and other foods that may cause increased calcium absorption and urinary calcium excretion.
“Changing your diet to prevent kidney stones can be very difficult,” says Dr. Rule. “So knowing the most important dietary factors in preventing kidney stone recurrence can help patients and providers know what to prioritize.”
Low dietary intake of calcium and potassium was a stronger predictor than fluid intake of recurrent kidney stone formation, says Api Chewcharat, MD, first author of the paper and postdoctoral researcher at Mayo Clinic at the time of the article. ‘study. “That’s not to say high fluid intake isn’t important. We just didn’t find any benefit from increasing fluid intake in 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 early kidney stones and recurrent kidney stones. This daily intake is in line with the daily nutrition recommended by the Ministry of Agriculture.
Although a higher potassium intake is also recommended, the USDA does not make a recommendation for daily potassium intake. The study also does not recommend a level of intake.
Dr Chewcharat says the takeaway is that patients should add more fruits and vegetables rich in calcium and potassium to their diet. Potassium-rich fruits include bananas, oranges, grapefruits, cantaloupes, honeydew melons and apricots. Vegetables include potatoes, mushrooms, peas, cucumbers and zucchini.
Reference: “Dietary Risk Factors for Incident and Recurrent Symptomatic Kidney Stones” August 1, 2022, Mayo Clinic Proceedings.
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 the Mayo Clinic – and Erin Taylor, MD, of the VA Maine Healthcare System. Dr. Schulte reports personal fees from OxThera Inc. outside of work on this study. Dr. Lieske reports grants and/or other fees from pharmaceutical and related companies identified in the article – all outside of this study and all paid to Mayo Clinic. The other authors report no competing interests.