General Nutrition Guidelines for All Stone Formers

Abstract

There are multiple nutrition-related influences on nephrolithiasis including body weight and obesity, fluid intake, sodium intake, and the acid–base balance of the diet. Obesity and related factors such as insulin resistance and hyperinsulinemia create metabolic abnormalities, such as lower urine pH and increased urinary calcium and oxalate excretion, increased uric acid and increased calcium oxalate stone risk, respectively. For this reason, weight loss may be an appropriate intervention to lower recurrence risk. In addition, stone formers have been shown to have lower 24-h urine volume than healthy controls, and increasing fluid intake decreases stone risk. High sodium intake can increase urinary calcium excretion, thus increasing the potential for the formation of calcium-containing stones. Helping patients replace excessive intake of processed foods, which are typically high in sodium, with fresh foods may be effective in reducing hypercalciuria. Diet may influence urine citrate, an inhibitor of calcium oxalate and calcium phosphate stone formation. If indicated, patients may be able to raise urinary citrate excretion by reducing the acid load of the diet. A high intake of purines from animal flesh may contribute in susceptible individuals to hyperuricosuria. Correcting diet-related stone risk factors for low urine volume, hypercalciuria, hypocitraturia, and hyperuricosuria may help lower patients’ risk of stone recurrence.