Dietary Management of Urinary Risk Factors in Renal Stone Formers

Abstract

Three hundred and ninety-two stone formers were investigated to exclude systemic disorders and to define the presence of haematological and urinary abnormality commonly associated with stone disease. Increased urinary excretion of calcium, oxalate or uric acid was found in 40% and there was more than one abnormality in 16% of the patients. The dietary habit of stone formers did not differ significantly from that of control subjects. Dietary advice to increase the consumption of fibre and reduce the consumption of sugar, refined carbohydrates and animal protein produced a significant reduction in the urinary excretion of calcium, oxalate and uric acid. We consider that reduction of the nutrient density of the diet by this means is the first line of management of idiopathic stone formers.

Metabolic Response to Refined Carbohydrates in Idiopathic Urolithiasis

“…There is also the evidence that sugar or sugar products increase the absorp tion of calcium from the intestine and also induce calciuria possibly through other mechanisms [5,6,13]. Fur thermore, it has been demonstrated that reduction of the nutrient density of the diet and addition of fibre to the diet reduce the urinary excretion of calcium, oxalate and uric acid in stone formers [ 14]. It is therefore highly prob able that there is an aetiological relationship between diet and urolithiasis.…”

Dietary Structure and Renal Stone Disease

“…The management of known stone formers is of course of first concern to doctors since very recent work has shown that a proportion of stone formers are maladapted to the nutrient-rich, fibre-dilute diet of our society in that their metabolic response to some nutrients is significantly greater than other people who are 'normal' or in other words 'adapted' to present food habits (Rao et al, 1982b). Whilst it is correct to concentrate on changing the dietary habit of those most at risk, i.e.…”

Renal Excretion of Calcium

“…In addition to the calcium content of food, dietary factors altering calcium availability, such as phosphate (Farquharson et al 1931;MaIm 1953;Lotz et al 1964;O'Brien et al 1967;Heyburn et al 1982) and fibre (Shah et al 1980;Rao et al 1982) and affecting absorption, such as sugars (Wasserman and Taylor 1969;Condon et al 1970) and amino acids (Wasserman and Taylor 1969), influence the relationship between urinary calcium and dietary calcium intake. Dietary sodium (King et al 1964;Kleeman et al 1964;Edwards and Hodgkinson 1965a;Modlin 1966;Phillips and Cooke 1967) and protein (Sherman 1920;McCance et al 1942;Anand and Linkswiler 1974;Margen et al 1974;Robertson et al 1979b) increase urinary calcium but the effect is probably mediated in the kidney rather than the gut.…”