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Preface and Contents

Stone Disease

Prevention of Stone Disease

132. Save Your Kidneys
Prevention of urinary stones

“Once a kidney stone former, always a stone former.” Urinary stones recur in about 50 to 70% of persons. On the other hand, with proper precautions and treatment the recurrence rate can be reduced to 10% or less. Thus, all patients who suffer from kidney stones should follow preventive measures.

General measures

Diet is an important factor that can promote or inhibit formation of urinary stones. General measures useful to all patients with urinary stones are:

For diagnosis of stones in the urinary tract, CT scan, sonography and X ray are the most important investigations.
1. Drink lots of fluid
  • A simple and most important measure to prevent formation of stone is to drink plenty of water, drink plenty of water and drink plenty of water. Drink 12 - 14 glasses (more than 3 liters) of water per day. To ensure adequate water intake throughout the day, carry a water bottle with you.
  • Which water to drink is a dilemma for many patients. But remember, to prevent formation of stone the quantity of water is more important than the quality of water.
  • For stone prevention, formation of a sufficient volume of urine per day is more important than the volume of fluid taken. To ensure that you are drinking enough water, measure the total volume of urine per day. It should be more than 2 - 2.5 liters per day.
  • Urine color or concentration may suggest how much water you are drinking. If you drink enough water throughout the day, the urine will be diluted, clear and almost watery. Diluted urine suggests a low concentration of minerals, which prevents stone formation. Yellow, dark, concentrated urine suggests inadequate water intake.
  • To prevent stone formation make it a habit to drink two glasses of water after each meal. It is particularly important to drink two glasses of water before going to bed and an additional glass at each night time awakening. If you need to wake up several times during the night to urinate, you have probably drunk enough fluids during the day and night.
  • Higher fluid intake is recommended in physically active people on hot days, because a significant amount of water is lost through perspiration.
  • Intake of fluids such as coconut water, barley or rice water, citrate- rich fluids such as lemonade and pineapple juice, helps in increasing total fluid intake and prevention of stone.
Plenty of fluid intake is the simplest and most essential measure for prevention and treatment of urinary stone.
134. Save Your Kidneys
Which fluids are preferred to prevent urinary stone?

Intake of fluids such as coconut water, barley or rice water and citrate- rich fluids such as lemonade, tomato juice or pineapple fruit juices helps in the prevention of stone. But remember that at least 50% of the total fluid intake should be water.

Which fluids should be avoided by a person with urinary stone?

Avoid grapefruit, cranberry and apple juice; strong tea, coffee, chocolate and sugar sweetened soft drinks such as colas. These beverages have been associated with an increased risk of stone formation.

2. Salt restriction

Avoid excessive salt intake in diet. Avoid pickles, chips and salty snacks. Excessive quantities of salt or sodium in the diet can increase the excretion of calcium into the urine and thereby increase the risk of formation of calcium stones. Sodium intake should be restricted to less than 100 mEq or 6 grams table salt per day to prevent stone formation.

3. Decrease intake of animal protein

Avoid non-vegetarian food such as mutton, chicken, fish and egg. These animal foods contain high uric acid/purines and can increase the risk of uric acid and calcium stones.

CHP. 19. Stone Disease 135.
4. Balanced diet

Eat a balanced diet with more vegetables and fruits that reduces acid load and tend to make urine less acidic. Eat fruits such as banana, pineapple, blueberries, cherries, and oranges. Eat vegetables such as carrots, bitter gourd (karela-ampalaya), squash and bell peppers. Eat high-fiber containing foods such as barley, beans, oats, and psyllium seed. Avoid or restrict refined foods such as white bread, pastas, and sugar. Kidney stones are associated with high sugar intake.

5. Other advice

Restrict intake of vitamin C to less than 1000 mg per day. Avoid large meals late at night. Obesity is an independent risk factor for stone formation.

Clean, transparent, water- like urine denotes adequate fluid intake.
Special measures
1. To prevent calcium stone
  • Diet: It is a wrong concept that calcium should be avoided by patients suffering from kidney stones. Eat a healthy diet with calcium, including dairy products, to prevent stone formation. Dietary calcium binds with oxalate in the gut which limits intestinal oxalate absorption and subsequently reduces stone formation. On the other hand, when dietary calcium is reduced, unbound oxalate in the gut can be easily absorbed from the intestines to promote formation of oxalate stones.
  • Avoid calcium supplements as well as a diet that is low in calcium, because both increase the risk of stone development. Dietary sources of calcium such as dairy products are preferred over oral calcium supplements for patients at risk for the development of kidney stones. If oral calcium supplements are necessary, they should be taken with meals to reduce the risk.
  • Medication: Thiazide diuretics are helpful in the prevention of calcium stones because they limit the excretion of calcium in the urine.
Restriction of salt intake in diet is very important for the prevention of calcium stones.
136. Save Your Kidneys
2. To prevent oxalate stone

People with calcium oxalate stones should limit foods high in oxalate. Foods rich in oxalate include:

  • Vegetables: spinach, rhubarb, okra, (lady finger), beets and sweet potatoes.
  • Fruits and dry fruits: strawberries, raspberries, chiku, amla, custard apples, grapes, cashew nuts, peanuts, almonds and dried figs.
  • Other foods: green pepper, fruit cake, marmalade, dark chocolate, peanut butter, soybean foods and cocoa.
  • Drinks: grapefruit juice, dark colas, and strong or black tea.
3. To prevent uric acid stone
  • Avoid all alcoholic beverages.
  • Avoid foods high in animal protein such as organ meat (e.g. as brain, liver, kidney), fish especially those without scales (e.g. anchovies, sardines, herring, trout salmon), pork, chicken, beef and egg.
  • Restrict pulses, legumes like beans or lentils; vegetables like mushrooms, spinach, asparagus and cauliflower.
  • Restrict fatty foods such as salad dressings, ice cream, and fried foods.
  • Medication: Allopurinol to inhibit uric acid synthesis and decrease urinary uric acid excretion. Potassium citrate to maintain urine alkaline, as uric acid precipitates and forms stones in acidic urine.
  • Other measures: weight reduction. Obese patients are not able to alkalinize urine and this increases the risk for the formation of uric acid stones.
Beware. Restriction of calcium in the diet will promote stone formation!