My approach to my osteoarthritis, which is severe enough to warrant knee replacement, has been to do as much as I can on my own.
A few months ago I removed dairy products from my diet. After a few weeks I noticed a reduction in knee pain and stiffness. I wondered if there were a connection.
Of course I went to the web. I found a variety of articles, some saying some components of cows' milk are good for certain types of rheumatoid arthritis (I did not find any that said they were good for osteo) and several that discussed food sensitivities in those with many types of arthritis. Many of these articles warned that milk sensitivity can mean stiffness and pain in arthritic patients. This article, written in 1985, discusses an experiment with one woman, a controlled study, and concludes that milk had significant effects on her arthritis.
The articles that promote milk only suggest there may be a component or two that helps with the arthritis but that this correlation is not yet proven.
A significant problem with studies of one or a few elements of a natural product is that they may well have different effects, even opposite effects, taken by themselves and taken as part of the whole. Far more useful are studies that examine the whole food itself, not inside a test tube but inside a person.
It appears that I may be onto something, that dairy products can exacerbate arthritis symptoms. Certainly my own unscientific experience tells me so. Other, more scientific research (see, for example, The China Study by Colin Campbell) tells us that milk products have even more serious negative effects on our bodies. It is well for everyone, not just arthritis sufferers, to avoid drinking cows' milk. Leave it for the calves.
I'm glad you asked. I simply moved into a totally vegan diet, primarily for ethical reasons. It was then that I noticed it was having a beneficial effect on my health. I had been a vegetarian for many years so the main change was cutting out dairy and eggs.
Interestingly, dairy products are not the best source of calcium. The protein in dairy products interferes with the absorbtion of calcium. There are some interesting studies showing that plant products are more effective. Most of the world does fine without dairy products and so did Americans for many years as well.