If you're concerned about arthritis, you should switch to tea. Studies have only been performed on mice, but the results are encouraging. Again, it's the polyphenols that seem to prevent the onset of disease. Mice were given either green tea or water, and the mice who drank the green tea were less likely to develop arthritis and those that did, had much milder symptoms.
References
Heavy Coffee Drinking May Raise Rheumatoid Arthritis Risk
Coffee Linked to Arthritis
Green Tea Can Help Prevent Rheumatoid Arthritis
Green Tea May Combat Arthritis
