Gut bugs as bone drugs

Osteoporosis is a chronic disease characterized by a lowered bone mineral density (BMD) that can lead to debilitating bone fractures. It is estimated to affect 9.9 million adults in the U.S.^[1], while another 43.1 million have osteopenia, the condition between normal bone density and osteoporosis. Postmenopausal women have the greatest risk of developing osteopenia or osteoporosis.

The first line of recommended treatments^[2] by the National Osteoporosis Foundation is modifying the diet to include adequate amounts of calcium and vitamin D, and engaging in regular weight-bearing exercise to maintain bone strength. However, research^[3] over the past few years has suggested that the gut microbiome and probiotic therapy can play a role in bone health. Some researchers have gone so far as to coin a term for this relationship: “gut microbiota-bone axis^[4].”

Of particular interest is a species of lactic acid producing bacteria called Lactobacillus reuteri ATCC PTA 6475 (L. reuteri 6475). Several studies using mice^[3] have shown L. reuteri 6475 can increase BMD and reduce bone loss. However, to date, there have been no human interventions examining the link between this organism and bone health. The randomized, controlled human trial reviewed here is the first such human study.

Osteoporosis and osteopenia are diseases of bone loss often managed through diet and exercise. Emerging evidence indicates the gut microbiome plays a role in bone health, and several animal studies have suggested that Lactobacillus reuteri ATCC PTA 6475 (L. reuteri 6475) can increase bone mineral density and reduce bone loss. The study under review is the first human intervention to evaluate how L. reuteri 6475 affects bone health.