Yes, food plays a HUGE part in health. Even though I am only recently on the candida diet, I have been learning about the connection between food and health and making small changes for several years now. Small changes, which add up to a lot. And it is those changes, which became habits and normal every day lifestyle that made the candida diet a lot more doable than it otherwise would have been. I actually suspected candida a few years ago and attempted the candida diet, but failed miserably. It was just too hard to stick to when I didn't "really" know I had candida. However, a food intolerance test came back with a high intolerance to yeast, which is how I was diagnosed. Between then and now I got more serious about reducing sugar and bread and adding more veggies, etc. So when I found out I couldn't have ANY sugar or bread, I was already on the right track.
The first book I read that really made an impact on me in this regard is Jordan Rubin's The Great Physician's Rx to Health and Wellness. He almost died from Crohn's, severe candida and about 15 other ailments. After trying a multitude of different treatments from doctors all over the world, some natural and some conventional (his own father was a naturopathic doctor), he finally figured out how Biblical eating was the healthiest way to eat and got well.
Another book I love, which is an inspirational easy read with practical tips, is Mariel Hemingway's Healthy Living from the Inside Out, along with her cookbook, Mariel’s Kitchen: Simple Ingredients for a Delicious and Satisfying Life.
I'm also a big fan of Dr. Mercola and read his newsletter daily. http://articles.mercola.com/sites/current.aspx
You might want to go to his site and do a search for RA and see what you find.
Good luck in your recovery!