I don't know about the supplement. They'd have to show me a mountain of proof before I start taking one more pill!
I do eat "anti-inflammatory" foods on a regular basis and I avoid all trans-fats. Hard to say whether it's helped my arthritis or not. I do think I'm healthier in a general sense. Steadier blood pressure, lower weight, my cholesterol is very good - surprising for someone who's had RA as long as I have.
I make a great yellow rice and peas (turmeric spice turns the rice bright yellow). As a side dish with some lean chicken and steamed broccoli - yummy! It's a common spice in Thai cuisine as well.
Here's the NCCAM page on turmeric: http://nccam.nih.gov/health/turmeric/
PS - you can drink it in a tea too. I've seen ginger and turmeric teas.