Sucrose and Idiopathic Renal Stone

Abstract

Idiopathic renal stone comprises more than SO per cent of kidney stone disease. Whilst the incidence rate in the Western World is high, that in Africa south of the Sahara is very low. Epidemiological studies point to a dietary aetiology as the basis for stone formation in the kidney.

A number of dietary constituents increase the urinary risk factors for stone formation and one of these is sucrose. The sucrose effect is exaggerated when it is consumed in certain forms. There is also the evidence that a third of a normal population responds in an exaggerated manner in respect of an increased excretion of urinary risk factors when sucrose is consumed and this phenomenon has been noted in over 70 per cent of idiopathic stone formers. In studying the mechanism of this, insulin was found to influence distal renal tubular function to increased calcium excretion. Stone formers with an exaggerated urinary risk factor response to sucrose were found to have abnormally high and sustained blood levels of insulin following a standard glucose test meal. Where sucrose or sucrose products are in abundance, quite apart from its effect in increasing urinary risk factors in the population in general, there is particular vulnerability of a significant sub group within the population with this type of insulin response. Sucrose furthermore is known to induce nephrocalcinosis in the kidney of the rodent and similar calcific lesions have been found in the kidney substance of man and these have been observed to begin to appear within the first decade of life. Sucrose has also been observed in man to increase the excretion rate of an enzyme which is identified with renal tubular cell damage.