Galactooligosaccharides Improve Mineral Absorption and Bone Properties in Growing Rats through Gut Fermentation

Abstract

Galactooligosaccharides (GOS), prebiotic nondigestible oligosaccharides derived from lactose, have the potential for improving mineral balance and bone properties. This study examined the dose-response effect of GOS supplementation on calcium and magnesium absorption, mineral retention, bone properties, and gut microbiota in growing rats. Seventy-five 4-week-old male Sprague-Dawley rats were randomized into one of five treatment groups (n = 15/group) and fed a diet containing 0, 2, 4, 6, or 8% GOS by weight for 8 weeks. Dietary GOS significantly decreased cecal pH and increased cecal wall weight and content weight in a dose-dependent manner (p < 0.0001). Fingerprint patterns of the 16S rRNA gene PCR-DGGE from fecal DNA indicated the variance of bacterial community structure, which was primarily explained by GOS treatments (p = 0.0001). Quantitative PCR of the samples revealed an increase in the relative proportion of bifidobacteria with GOS (p = 0.0001). Net calcium absorption was increased in a dose-response manner (p < 0.01) with GOS supplementation. Dietary GOS also increased (p < 0.02) net magnesium absorption, femur ⁴⁵Ca uptake, calcium and magnesium retention, and femur and tibia breaking strength. Distal femur total and trabecular volumetric bone mineral density (vBMD) and area and proximal tibia vBMD increased (p < 0.02) with GOS supplementation. Trabecular-rich bones, that is, those that rapidly turn over, were most benefited. Regression modeling showed that GOS benefited calcium and magnesium utilization and vBMD through decreased cecal pH, increased cecal wall and content weight, and increased proportion of bifidobacteria.

Impact of a Resistant Dextrin on Intestinal Ecology: How Altering the Digestive Ecosystem with NUTRIOSE®, a Soluble Fibre with Prebiotic Properties, May Be Beneficial for Health

“…This acidic environment may also help to solubilize minerals and further increase their absorption. 23 Colonic short-chain fatty acids -indicators of the fermentation processes occurring after fibre consumption -are difficult to monitor in human clinical studies. 24 Study 1 described here examined faecal short-chain fatty acids but found no significant changes after consumption of NUTRIOSE ® .…”

Osteoimmunology: from mice to humans

“…56 Also the effects of prebiotics have been evaluated in animal models showing a positive effect on GM composition and subsequently on bone mass. 57 According to the data obtained in mice one may speculate that an unfavorable GM composition may increase inflammation and hence favors postmenopausal bone loss. However, data obtained in humans are scarce.…”

Diverse galactooligosaccharides consumption by bifidobacteria: implications of β-galactosidase—LacS operon

“…Numerous studies have revealed that GOS can stimulate the growth or activity of endogenous bifidobacteria, leading to a variety of host benefits. [8][9][10][11][12][13][14] For instance, Silk et al demonstrated in their clinical trial that GOS specifically increased the numbers of bifidobacteria in patients with irritable bowel syndrome and alleviated their symptoms. 11) Moreover, GOS and bifidobacteria are also given in a combined treatment referred to as a synbiotic, with the aim of enhancing the effect of exogenous bifidobacteria.…”