Addition of inulin to breakfast does not acutely affect serum ionized calcium and parathyroid hormone concentrations

The aim of the present study was to investigate the effects of inulin on calcium metabolism. The study consisted of two separate parts both of which had a randomized two-period cross-over design.

Fifteen young healthy women volunteered to participate in this study. During the first part of the study, cheese containing 210 mg of calcium, either with 15 g of inulin or without any inulin, was ingested at breakfast, and in the second part, 210 mg of calcium as a supplement, either with 15 g inulin or without inulin, was ingested. The whole day's diet was standardized. Before breakfast, and 2, 4, 6 and 8 h after breakfast, a blood sample was taken, and intact parathyroid hormone (iPTH), ionized calcium (iCa) and total calcium were measured. Urine was collected throughout the day, and the 8-, 12- and 24-hour calcium excretion was calculated.

The iPTH or iCa concentration curves (AUCs) did not differ over 8 h, whether or not inulin was consumed at breakfast. The postload urinary calcium excretion was not affected by the inulin.

Fifteen grams of inulin in fresh cheese or with a calcium supplement (210 mg Ca) taken at breakfast does not acutely affect the markers of calcium metabolism as opposed to a corresponding breakfast without inulin.