1. Water and Beverages:
a. Patient should be encouraged to drink than 2 liters of fluids per day.
b. Citrus juices (lemon and oranges) are protective for stone formation. Natural juices are highest in citrate and potassium.
c. Caffiene leads to more excretion of calcium, and hence increases the risk for stone recurrence in calcium stone formers.
d. Soda flavored with phosphoric acid increases stone risk, whereas those with citric acid decreases the risk.
2. Protein Restriction:
a. Incidence of kidney stones increases with an increase in animal protein intake.
b. Protein intake increases urinary calcium, oxalate, and uric acid excretion.
c. Protein intake increases intestinal absorption of calcium. Hence, high meat intake increases the risk of calcium oxalate stone disease.
d. Dietary Approaches to Stop Hypertension- (DASH) style diet is rich in fruits and vegetables, moderate in low-fat dairy products, and low in animal proteins. A higher DASH score diet is associated with a lower risk of kidney stone formation, probably due to high urinary citrate.
3. Sodium Restriction:
Important to prevent recurrent kidney stones. Very high sodium intake in salts leads to high calcium excretion, high pH (alkaline), and low citrate excretion in urine. These lead to increased chances for crystallization of calcium salts in urine.
Low animal protein + Low sodium diet + moderate calcium in diet: Reduce stone episodes by roughly 50%.
4. Managing Obesity:
a. Obesity is associated with impaired carbohydrate tolerance and inappropriate calcium responses to glucose ingestion.
b. High BMI (Basal metabolic rate) leads to high urinary excretion of oxalate, sodium, uric acid, calcium, and phosphorus, as well as low pH (acidic).
c. High BMI, larger waist size, and weight gain are associated with a high risk of stone episodes.
d. Obesity is also associated with gouty diathesis, hypocitraturia, and hyperuricosuria.
5. Metabolic syndrome (Impaired glucose tolerance, Hypertension, Obesity):
a. Obese patients have acidic urine which leads to stone formation.
b. Type 2 diabetes mellitus is also associated with acidic urine pH.
6. Impact of weight-loss diets:
A low carbohydrate, high protein diet delivers a marked acid load to the kidneys, and therefore increases the risk of kidney stone formation and also may increase bone loss.
7. Bariatric surgeries: Increases the risk of calcium oxalate stones.
8. Role of dietary calcium:
a. Dietary calcium restriction actually leads to an increase in stone formation due to increased oxalate absorption in the intestine.
b. Calcium supplements are safe when taken with meals.
Hope these dietary recommendations will be helpful. Stay in touch with your physician and monitor your health regularly.