Lactulose stimulates calcium absorption in postmenopausal women

Animal studies have indicated that calcium absorption is increased by lactu lose, a synthetic disaccharide. Therefore, the influence of lactulose on ca lcium absorption was measured in postmenopausal women who may benefit from the possible enhancing effect of lactulose on calcium absorption. Twelve po stmenopausal women drank 100 mi of water containing 5 or 10 g of lactulose or a reference substance at breakfast for 9 days. The three treatments were given according to a randomized, double-blind, cross-over design, separate d by two 19-day wash-out periods. On the 8th day of each treatment period, Ca-44 dissolved in orange juice was drunk immediately after the solution wi th the study substance and just before a standard breakfast with 162 mg of carrier calcium. Within half an hour, Ca-48 was given intravenously. Based on isotope ratios measured in urine collected before and until 36 h after i sotope administration, true fractional calcium absorption was calculated. C alcium absorption during the treatments with the reference substance, 5 g a nd 10 g of lactulose was (mean +/- SD) 27.7 +/- 7.7, 30.0 +/- 7.6, and 32.2 +/- 7.0, respectively. A significant difference in calcium absorption was found between the highest dose of lactulose and the reference treatment (p < 0.01). A significant linear trend was found between the dose of lactulose and its positive effect on calcium absorption. In conclusion, in postmenop ausal women a 9-day consumption of lactulose increases calcium absorption i n a dose-response way. More research is warranted to explore holy lactulose stimulates calcium absorption and whether it is able to improve calcium ba lance and/or to attenuate the rate of aging bone loss.