The influence of refined carbohydrate on urinary calcium excretion

In the course of study of the influence of varying the amount of refined carbohydrate (sugar and sugar products) in an otherwise standardised diet in 18 normal subjects it was evident that the analysis of 24-h urine collections failed to show the profound diurnal variation in urinary electrolyte excretion and, in particular in this instance, calcium excretion. The analysis of individually voided specimens showed some normal subjects to have spontaneously high peaks of urinary calcium concentration throughout the day even whilst on a diet with low refined carbohydrate content. Increase in the refined carbohydrate content of the otherwise standardised diet caused significant increase in the number of urines with a calcium concentration above 9 mmol/1. Refined carbohydrate, a common cinstituent in Western diets, can therefore influence urinary electrolyte excretion in such a way that there may be an increased risk of over-saturation with calcium oxalate.