Metabolic Response to Refined Carbohydrates in Idiopathic Urolithiasis

Abstract

The dietary habits of 139 stone patients and 20 control subjects were assessed to investigate the differential features, if any, of the eating pattern between the two groups. There was no significant difference between stone formers and controls, although the data for animal protein was inadequate for statistical analysis. In a separate study, 39 idiopathic calcium stone formers and 18 control subjects were studied by measuring the blood glucose, plasma insulin and glucagon levels following oral glucose. The insulin response was abnormal in 70% of the patients. Increased urinary risk factors for calcium oxalate oversaturation were significantly associated with patients who exhibited an abnormal insulin response.

Glucose Metabolism in Renal Stone Patients

“…Similarly to the findings of pre vious studies [1][2][3][9][10][11][12], an increment in urinary cal cium excretion following glucose ingestion was observed in the present study. Therefore, overconsumption of re fined carbohydrates, especially sugar-sweetened soft drinks, soda, and cakes which can rapidly induce calciuria in the fasting state [19], may be one of the major risk fac tors for stone formation in modern societies [8,20], a con clusion consistent with our previous observations [7].…”

“…Rao et al [9] reported that the mean daily consumption of sugar by stone patients was similar to that by controls and then speculated that some calcium stone patients suffered from abnormal metabolism of refined carbohydrates and that this was an etiologic factor in idiopathic calcium oxalate stones of the kidney. In the present study, however, 9 of 27 stone patients and 5 of 22 control subjects showed an abnormal plasma glucose response in the OGTT, and the incidence of impaired glucose tolerance was similar in both groups.…”

“…Some previous studies have concluded that the ex treme calciuric effect of oral glucose seen in stone patients is due to abnormal carbohydrate metabolism [2,9] or renal leakage of calcium [10]. However, other authors have concluded that the exaggerated calciuric response to oral glucose in stone patients is due only to their over weight condition and that there is no specific disorder of carbohydrate metabolism [11,12].…”

Increased Urinary Excretion of Glycosaminoglycans in Pregnancy and in Diabetes mellitus: A Protective Factor against Nephrolithiasis

“…Nevertheless, the incidence of nephrolithiasis during pregnancy and in diabetes mellitus is low, and probably lower than that observed in the population at large [4][5][6], Since the lithogenic processes are the consequence of an imbalance be tween urinary supersaturation, factors promoting and inhibiting crystallization, crystal growth and agglomera tion, it is possible that the lower calculosis incidence in these two situations -despite the existence of evident risk conditions -is due to the presence of an important inhibitory activity in the urine of these subjects. Without doubt, the glycosaminoglycans (GAGs) are among the substances that contribute highly in inhibiting urinary lithogenesis (7,8], Actually, the urinary GAG excretion in diabetes melli tus and in pregnancy was frankly high compared to controls (table I); in agreement with literature reports, hypercalciuria is also present (table I).…”