The Interplay Between Intestinal Microbiota & Bone Health
By Nadia Zaman, DO
Intestinal microbiota describes the myriad of microorganisms that reside in the human intestine, developing at birth and changing over time as a result of diet, inflammation, environmental exposure and antibiotic administration (1). It is thought to be comprised of 1014 bacteria, representing more than 5000 species and over 5 million genes (2). Intestinal dysbiosis, which is defined as a shift in the microbial constitution of the gut to an unhealthy state, has been linked to a wide range of disorders, such as diabetes mellitus type 2, obesity and inflammatory bowel diseases (IBD). Recent studies have started to look at the relationship between the gut microbiome (GM) and bone health, as well as its link to musculoskeletal problems such as osteoarthritis (OA) (1). OA is a common arthropathy, affecting over 30 million American adults. The development of OA can lead to decreased functional mobility and gait impairment over time, often leading many individuals to pursue joint replacements after other more conservative management strategies fail to stave off longterm debilitation. Until recently, how GM affects bone physiology and health was largely ignored, but scientists and clinicians alike have begun to look at how dietary changes, such as the administration of pre- and probiotics, can lead to changes in bone health.
Numerous animal model studies have shown that the oral administration of probiotics to arthritic rats and germ-free mice led to reduced expression of pro-inflammatory cytokines1 and increase in trabecular bone volume (3,4, respectively). Human studies looking at the use of probiotics still remain to be completed; however, a one-year RCT looked at the use of a prebiotic called inulin in adolescent girls and found that girls who were supplemented were found to have greater bone mineral density on DEXA scanning (2,5). There has also been a link associated between spondyloarthritis and gut inflammation in humans, such as ankylosing spondylitis and IBD (4).
Pre- and probiotics are generally considered safe to consume with little to no adverse effects and are ubiquitous in their availability to the general population. Prebiotics are non-digestible fibers that are found in many fruits and vegetables, such as leeks, asparagus, chicory root, onions and bananas (1,3). Bacteria of the genera Lactobacillus, Bifidobacterium, Escherichia, Enterococcus and Bacillus are considered probiotics and can be found in appropriate amounts in dairy products, such as yogurt, as well as in powder and tablet forms (3). As more evidence comes to light, physicians are turning to multidisciplinary approaches to treating arthritic patients, often using anti-inflammatory diets rich in pre- and probiotics as part of the strategy to further enhance bone and cartilage health.
There is still much to be learned about how GM is linked to musculoskeletal health, but the research already conducted has shown promising results that by altering GM through dietary modifications, one may be able to provide patients an alternative treatment plan for arthritic processes.
References
1. Steves CJ, Bird S, Williams FM, Spector TD. The Microbiome and Musculoskeletal Conditions of Aging: A Review of Evidence for Impact and Potential Therapeutics. J Bone Miner Res. 2016;31(2):261–9.
2. Weaver CM. Diet, gut microbiome, and bone health. Curr Osteoporos Rep. 2015 Apr;13(2):125–30.
3. McCabe L, Britton RA, Parameswaran N. Prebiotic and Probiotic Regulation of Bone Health: Role of the Intestine and its Microbiome. Curr Osteoporos Rep. 2015 Dec;13(6):363–71.
4. Hernandez CJ, Guss JD, Luna M, Goldring SR. Links Between the Microbiome and Bone. J Bone Miner Res. 2016 Sep;31(9):1638–46.
5. Abrams SA, Griffin IJ, Hawthorne KM, Liang L, Gunn SK, Darlington G, et al. A combination of prebiotic short- and long-chain inulin-type fructans enhances calcium absorption and bone mineralization in young adolescents. Am J Clin Nutr. 2005; 82:471–6.
