I don't know, but if I eat too many sweets I tend to get more joint pain. I don't have an arthritis problem, but I notice my muscles feel better if I drink a lot of water and avoid sweets - I think sweets are considered "inflammatory" foods. Do you drink milk and eat dairy?? You might stop for a while to see if that helps. Lactose build-up (milk sugar) can cause cramps - pasteurized milk doesn't contain lactase unless it's been added back in after pasteurization, which means your body can't break down the sugars as easily. Anything that's hard to digest (refined foods, sweets, etc.) will upset your metabolism - if you can't break down the food soon enough, your body stores it - in your muscles and fat. If you have restless leg syndrome as well, try soda water w/ quinine in it - it eases the restlessness.

P.S. I get cramps in my legs when my lower back is out. Then I see a chiropractor. A good chiro can fix sciatica in one or two visits.