A kidney stone is a hard mass that forms from crystals in the urine. Normally, natural chemicals in the urine prevent stone formation. These are of following types:
calcium oxalate stones
calcium phosphate stones
uric acid stones
cystine stones
As the composition of kidney stones vary, dietary recommendations will also vary based on the minerals they contain. Almost 1 in 10 people will develop kidney stones in their lifetime. Dietary changes if followed can prevent further recurrence of kidney stones.
Though the dietary interventions can be specific to the type of kidney stones, here are a few dietary interventions to be followed in general.
- Staying hydrated: water helps to dilute the chemicals that form stones. One must drink at least 12 glasses of water a day.
- Calcium rich food: Most often, calcium is assumed to be the culprit for kidney stones but this is not true. Calcium actually binds with oxalate & reduces the chances of stone formation. Hence one can include good sources of calcium like milk, yogurt, cottage cheese, and other types of cheeses. Vegetarian sources of calcium include legumes, calcium-set tofu, dark green vegetables, nuts, seeds.
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Limit foods with high oxalate content: Foods such as nuts and nut products, peanuts, rhubarb, spinach, wheat bran are high in oxalate.
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Limit sodium intake: This can be obtained by limiting salt intake to 1,500 to 2,000 milligrams a day. Sodium and calcium shar e the same transport in the kidney eating high sodium foods will increase calcium leakage in the urine. Therefore, a high sodium diet can increase chances for developing kidney stones.
- Avoid Colas: Cola is high in phosphate, another contributor to formation of kidney stones.
- Limit intake of meat: High meat intake can increase uric acid, calcium, and oxalate concentrations in the urine, which can increase the risk of stone formation. It is recommended to only eat 6-8 oz of meat per day (inclusive of beef, pork, poultry, and seafood).
- Avoiding high purine food : Red meat, organ meats, and shellfish have high amounts of purines. High purine intake leads to a higher production of uric acid and a larger acid load for the kidneys to excrete. The high acid concentration of the urine favors stone formation. Thus, to prevent uric acid stones, one must cut down on high-purine foods such as red meat, organ meats, beer/alcoholic beverages, meat-based gravies, sardines, anchovies and shellfish.
- Consult a physician before starting any Supplements: Certain supplements like fish oil and vitamin B6 can help reduce the chance of getting them. It is always better to discuss with the physician before starting supplements especially if there is a history of kidney stones.
Thus, Kidney stones can be effectively managed and prevented with dietary interventions. Staying hydrated and avoiding certain foods that are high in salt and sugar, and pairing calcium with oxalate rich foods are important elements of a kidney stone diet.
References:
- Eating, Diet, & Nutrition for Kidney Stones | NIDDK (no date). Available at: https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-stones/eating-diet-nutrition (Accessed: 2 April 2022).
- Foods That Can Causes Kidney Stones: High Oxalate Foods to Avoid (no date). Available at: https://www.webmd.com/kidney-stones/kidney-stones-food-causes (Accessed: 2 April 2022).
- Gul, Z. and Monga, M. (2014) ‘Medical and dietary therapy for kidney stone prevention’, Korean Journal of Urology, 55(12), pp. 775–779. doi: 10.4111/KJU.2014.55.12.775.
- Han, H. et al. (2015) ‘Nutritional Management of Kidney Stones (Nephrolithiasis)’, Clinical Nutrition Research, 4(3), p. 137. doi: 10.7762/CNR.2015.4.3.137.
- Kidney Stones Diet and Nutrition Guidelines | Foods to Avoid (no date). Available at: https://www.pacehospital.com/kidney-stones-diet-and-nutrition-guidelines-foods-to-avoid (Accessed: 2 April 2022).
- Kidney stones - self-care: MedlinePlus Medical Encyclopedia (no date). Available at: https://medlineplus.gov/ency/patientinstructions/000135.htm (Accessed: 2 April 2022).
