Dietary Management In Urinary Calculi(kidney stones) - Urolithiasis

DIETARY MANAGEMENT IN URINARY CALCULI - UROLITHIASIS

Urinary calculi (kidney stones) may be found in the kidney, ureter, bladder or urethra as presented in Fig. 15-B. About 90% of all stones contain calcium. The occurrence of kidney stones may be due to an outcome of different nutritional status, dietary habits and environmental factors such as temperature and humidity.

In warm climates, the urine volume is low and concentrated with urates, oxalates and calcium salts. Frequent urinary tract infection may contribute to the formation of stones. In India the most common type of calculi is calcium oxalate.

The diet should be low in oxalic acid and purine. Intake of calcium and phosphates should be reduced. Large amounts of fluid should be consumed to increase urine output. A dilute urine prevents the formation of stones.

When stones are composed of calcium, magnesium phosphates and carbonates the urine is alkaline and acid - ash diet is used. The acid ash diet should maintain the urine pH between 4.5 and 5 and with an alkaline ash diet, a urinary pH of 7.6 to 8 is maintained.

a. Planning acid ash Diet

A liberal fluid intake is important. Salt is used in moderation. Fruits and vegetables should not contribute more than 25 ml of base daily.

b. Planning alkaline - ash diet

If stones of uric acid or cystine type occur, an alkaline - ash diet is given. Alkaline producing foods like fruits, vegetables and milk are given while acid producing foods like meat, eggs and cereals are restricted Table 15.2 gives the list of Acid producing, Alkali producing and neutral foods.

c. Low oxalate diets

In the case of oxalate stones, foods that are a good source such as beans, chocolate, cocoa, potatoes, spinach, tea and tomatoes should be omitted.

Fluid

A liberal fluid intake of 3000 ml or more daily is essential to prevent the production of concentrated urine. Coconut and barely water, fruit juice and weak tea are given.