Urinary stone risk factors can result from improper diet and/or physiologic abnormalities.Recurrence rate of kidney stones is over 50%.Dietary factors are important in kidney stone formation.Dietary recommendations in nephrolithiasis (kidney stones) should be based on a 24 hour urine collection.Diet changes alter the results of urine analysis and alter the type of stones formed and reduce the risk of stone recurrence.
Stones due to malnutrition in early life are common in parts of Turkey, Iran, India, China, Indochina, Indonesia and much of Asia. The incidence is reduced when social conditions and diets improve.Calcium oxalate stones are most common, followed by calcium phosphate, struvite, cysteine and uric acid stones (in that order.)
High urine calcium is the most common cause of stones in children and adults.A protein rich diet, refined carbohydrates and high sodium play roles in calcium oxalate stones.Some people have a genetic predisposition for calcium oxalate stones.
Dietary improvement in the traditional childhood bladder stone belt of Asia reduced the risk of bladder stones.The diet which seems to lead to bladder stones in children is a poor diet with low animal protein, calcium and phosphate and high in cereals and acid-forming foods.This leads to ammonium ions, urate ions, ammonium acid urate crystals and stones.A low sodium/high potassium diet (low acid) is beneficial in children at risk for stones.
When there is dietary oxalate from leaves and vegetables, the stones may contain calcium oxalate.Use of whole wheat flour as a staple in children can lead to urine with high specific gravity and high urinary concentrations of calcium, phosphorus, magnesium, oxalate and uric acid.
“Urine flow of at least 1 ml/kg/hour almost eliminates the risk of supersaturation for calcium oxalate, calcium phosphate and uric acid” and protects from kidney stones.A higher water intake is suggested in cystenuria and xanthinuria.The use of milk should keep the intake of calcium and phosphates within the RDA (recommended daily allowance.)
People with hypocitraturia should try citrate supplementation, such as potassium citrate, and take adequate water intake.This includes children.
In children with stones, the urine calcium is studied first.If the urinary calcium is normal, other studies can be done.Often, a low sodium/high potassium diet may be therapeutic.The use of potassium citrate may protect from calciuria.It is difficult to increase water intake in children.Milk intake should be within the RDA (recommended daily allowance) for calcium and protein.
Diet changes are the primary prevention of stones.The changes suggested depend on the results of a 24 hr. urine evaluation.After the dietary changes are made, repeat 24 hour urine studies should be done to test their benefit.
Modern diets are high in animal protein, refined carbohydrates and salt, making them acid.A higher dose of potassium and alkali is needed.Calcium should not be restricted.(The body does not, usually, absorb more calcium when needed.)
Calcium oxalate lithiasis is nutritionally treated by reducing or eliminating the oxalate intake from cocoa, chocolate, candies, black tea, excessive coffee use, spinach, rhubarb, asparagus, celery, parsley and tomatoes.They should avoid almonds, peanuts, cashews, walnuts, beetroot, cheeko, cocoa, chocolate, tomato, strawberries, eggplant, soy products, tofu, wheat bran and rice bran.