Transgalactooligosaccharides stimulate calcium absorption in postmenopausal women

The aim of this study was to investigate whether a product rich in transgalactooligosaccharides (TOS, Elix'or) stimulates true Ca absorption in postmenopausal women. The study was a double-blind, randomized crossover study, consisting of two 9-d treatment periods separated by a 19-d washout period. During the treatment periods, 12 subjects drank 200 mL yogurt drink twice (at breakfast and lunch) containing either TOS(20 g/d) or the reference substance, sucrose. On d 8 of each treatment period, Ca-44 and Ca-48 were administered orally and intravenously, respectively. Before and during the 36 h after isotope administration, urine was collected and the ratios of isotopes present were measured by inductively coupled plasma mass spectrometry (ICP-MS). From the isotope enrichments, true calcium absorption was calculated. TOS increased true calcium absorption 16%, from (mean +/- so) 20.6 +/- 7.0% during the reference treatment to 23.9 +/- 6.9% during the TOS treatment (P = 0.04, one-sided). In conclusion, in this study in postmenopausal women, greater Ca absorption was observed after consumption of a product rich in TOS (Elix'or) compared with the reference treatment. This increase in Ca absorption was likely due solely to TOS. The increased Ca absorption was not accompanied by increased urinary Ca excretion, meaning that TOS also may indirectly increase the uptake of Ca by bones and/or inhibit bone resorption.