I've been off gluten for years, dairy too. I suffered from all kinds of things from irritable bowel to arthritis.
Our digestive system simply isn't designed to deal with that stuff. I recently spoke with a couple who run a health retreat and have found that a diet based on plants provides everything we need and decreases the risks of cancer, type II diabetes, causes weight loss, stronger heart, eyes. And the list goes on.
Gluten, and wheat in particular is very aggressive to our alimentary canal. And in its current form (wheat is high genetically modified) has only been around for a very short time.
I would also suggest losing sugar and animal fats for a while.