All of them. Osteoarthritis is a result of inflammatory process run amuck. We need the inflammatory process to maintain our health, to heal to mediate normal body functions. When we have too much ongoing inflammation that is occurring at a greater rate than tissue replacement we get degenerative arthritis or DJD in the joints. Abnormal stress on bones due to loss of muscle tone can contribute to this as well by stimulating osteoclasts on bones. In the case of rheumatoid arthritis we have a case of immune system signaling gone awry. The immune system has gotten mixed signals and now sees the body as an inflammatory event. How does the gut play a role in both conditions? 55% of the immune system is in the gut in the form of Peyer’s patches. They see the most foreign bodies in the form of food than any other part of the body. If they have a reaction to the food they are shown they can cross talk to the rest of the immune system in the body. If you combine this with another event that affects the immune system such as a flu illness, a vaccination (responsible doctors will not give an immunization to someone who is ill) or even exposure to toxic chemicals then the immune system has too much confusing inout and can develop an autoimmune status. Hope this answers your question.