Kidney stones are hard substances formed by the chemical remnants in urine. Urine usually contains several waste products that are dissolved in it. A stone is formed when it has too much waste and too little liquid to dissolve in, leading to crystal formation. This crystal unless passed out with urine from the body, gets combined together with other elemental waste in the body forming a larger object leading to more serious conditions where medical therapy would be required.
The prevalence of kidney stone disease is 12% in total India's population, out of which 50% are affected severely leading to critical kidney damage and kidney loss (1).
Kidney stones are of different kinds based on the composition of the stone:
1. Uric acid stone - this is a common type of stone formed by high amounts of uric acid. Higher purine intake leads to formation of monosodium urate which causes stone-formation. This is mostly seen as hereditary.
2. Calcium-oxalate stone – this is the most commonly seen stone, where calcium is combined with oxalate in urine. Lack of adequate hydration is one of the major reasons for this stone formation.
3. Struvite stone - These are less common and are usually seen because of infections in upper urinary tract.
4. Cystine stone - these are rare and usually tends to be hereditary.
Based on the type of stone and size of it, these may be treated in various ways. Uteroscopy, shockwave lithotripsy etc., are few among the treatments. Usually, a small stone can be passed out through urine by increasing the water intake and limiting certain stone-causing foods.
Severe backpain, chills, fever, blood in urine, nausea, vomiting, cloudy looking urine are some of the most commonly seen symptoms of kidney stones.
Possible risk factors for kidney stone formation are:
Drinking very less water
Family history
Diets – excess sugar, protein and salt intake
Obesity
Digestive diseases and weight related surgeries
Certain medical conditions like cystinuria
Certain supplements and medications like excess usage of laxatives, calcium-based antacids.
How do you reduce the risk of kidney stone formation?
Drinking enough water helps to keep urine less concentrated. Darker urine is concentrated; hence your urine should look light yellow or clear if you are hydrated.
Limit the intake of foods with high amounts of fructose-corn syrup.
Include more fresh fruits and vegetables which makes the urine less acidic.
Reduce salt intake.
Avoid crash-diets and maintain healthy body weight by following a balanced diet
Include more plant-based protein, as animal-based protein leads to acidic urine.
Dietary guidelines for kidney stones:
Ample hydration – 3-3.5L per day. This includes water, lemon juice. These are shown beneficial to prevent kidney stones. However, avoid sodas and other fructose-based juices.
Limit high oxalate foods - These are spinach, ladies’ finger, nuts like almonds etc., soy beans and its products, peanuts, tea, wheat bran, buckwheat and dark chocolate. Soaking and cooking these oxalate rich foods thoroughly can lower the oxalate content.
Adequate calcium intake – Calcium intake helps to prevent calcium-oxalate stone formation. Include dairy as part of your meals. However, avoid calcium supplements.
Moderate your protein intake – Choose plant-protein over animal protein.
Limit sodium intake – High sodium intake can cause increased calcium intake in the body which increases the stone formation.
Limit vitamin C supplements – Excess of these produces oxalate content in the body.
Avoid tea, as it increases the risk of kidney stones.
Include at least 1 kind of fluid in every meal.
However, your diet needs to be stone specific. These are the preventive measures that you can follow. But consult your doctor or dietitian to manage the kidney stones affectively.
References:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6352122/
https://www.kidney.org/atoz/content/kidneystones
https://www.mayoclinic.org/diseases-conditions/kidney-stones/symptoms-causes/syc-20355755
https://www.kidneyfund.org/kidney-disease/kidney-problems/kidney-stones/