Treatment with friendly bacteria that are widely used in probiotic supplements can strengthen bones, a study has found.
Healthy mice fed Lactobacillyus rhamnosus GG (LGG) insects experience an immune response that stimulates increased bone density.
The effect is attributed to the generation of butyrate, or butyric acid – a type of fatty acid produced by intestinal bacteria.
This in turn activates the T-cells regulator, part of the immune system.
Scientists hope this discovery will lead to new ways to treat fragile osteoporosis bone disease.
This condition, the main danger for women after menopause, can lead to paralyzing bone fractures and an increased risk of death.
Previous research in animals showed that probiotics can help prevent bone damage associated with disease, but scientists are not clear why.
Professor Roberto Pacifici, from Emory University in the US, who led the new research, said: "Because their mechanism of action in bone is unknown, they are considered a kind of alternative, esoteric, unproven treatment.
"Our aim is to identify the biological mechanism of probiotic action, a mechanism that makes sense for traditional scientists, hoping this will make probiotics the main treatment."
The team found that four weeks of LGG supplementation increased bone formation in female mice by stimulating the growth of intestinal bacteria that produce butyrate.
LGG has no effect on bone mass when mice are raised in a germ-free environment, indicating that it works in conjunction with other intestinal insects.
Both LGG and Butyrate induce an expansion of T-cell regulation in the bone marrow.
The T cells alternately secrete a protein called Wnt10b which is known to be very important for bone development, scientists report in the journal Immunity.
Prof. Pacifici said: "We were surprised by the potential of intestinal microbiomes (bacterial populations) in regulating bone and by the complexity of the mechanism of action of probiotics.
"In general, there is a lot of interest in the concept that intestinal bacteria regulate the function of distant organs. How this happened is largely unknown.
"We describe the detailed mechanism by which changes in the composition of intestinal microbiomes induced by probiotics affect the system much like a skeleton.
Lactobacillus rhamnosus GG is widely sold as an over-the-counter probiotic. It is said to balance the immune system, protect against allergies and irritable bowel syndrome (IBS), and help prevent infection. There are also claims that it has anti-cancer properties.
The team now plans to expand the research and investigate whether butyrate supplementation can combat osteoporosis.
Prof. Pacifici added: "Our findings need to be validated in human studies.
"If successful, this study could strengthen the use of butyrate or probiotics as a new, safe, and inexpensive treatment to optimize skeletal development in young people and prevent osteoporosis in the elderly."
– Press Association