Addition of Inulin to Breakfast Does Not Acutely Affect Serum Ionized Calcium and Parathyroid Hormone Concentrations

Background/Aims: 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. Methods: 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. Results: 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. Conclusion: 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.