Calcium and Bone Density
The major actors in the gut microbiome are called short-chain fatty acids (SCFA). These substances are made in large quantities in the colon when the right bacteria, the Bifidus, and Lactose, are growing prodigiously. One of these SCFAs is called proportionate. This substance has been shown to reduce cholesterol. However, by far the star SCFA is butyrate. This is the substance that does many good things in the colon and beyond. It is the nutrient for the colon cells themselves. It heals the colon wall and may reduce a leaky gut. A leaky gut allows unhealthy substances and inflammatory factors to slide through and into the blood stream. Some of these end up in the wall of the coronary arteries where they do not belong. The article below reviews these facts.
The next question of where in humans the calcium was absorbed and this was answered in 2007 in the following article. It is in the colon and prebiotics were the reason it occurred.
Of course, a most important question to be answered would be what happens to post-menopausal females who are prone to osteopenia and osteoporosis. The following article answeres this question. These older females did increase their calcium absorption when they took the prebiotic oligofructose-enriched inulin.
This very solid research means that this specific prebiotic, oligofructose-enriched inulin can be recommended to both the young when their bones are actively growing and to the postmenopausal females to enhance bone health.