Recently, we have begun to realize that the billions of microorganisms living in harmony with us have an influence on disease. Evidence is mounting that the gut microbiome, in particular, influences our metabolism and our immune system. Inflammatory states characterize many bone and joint diseases of ageing. Evidence is accumulating that the gut can contribute to inflammatory conditions. As the microbiome is modifiable this could represent a major therapeutic target.  To date, some of the best data relating the microbiome to bone disease is in osteoporosis and rheumatoid arthritis. Other diseases, in particular osteoarthritis, have received little attention to date, despite some promising suggestive findings.  In addition, there is increasing evidence that what we eat  is involved in the generation of disorders such as inflammatory conditions such as inflammatory bowel diseases, atherosclerosis, and type 2 diabetes. Nutrients can have short- and long-term effects on the composition of the microbiota. Standard American Diets (SAD) high in processed and sugary foods promote inflammation and atherosclerosis. The microbiota and its metabolic components produce a vast amount of metabolic byproducts that serve as important messengers between the diet, microbiota, and us. There now is scientific evidence to support the notion “you are what you eat,” and this process begins in early life.R