From the great Wikipedia:
Gluten (from Latin gluten, "glue") is a protein composite found in foods processed from wheat and related grain species, including barley and rye. It gives elasticity to dough, helping it to rise and to keep its shape, and often giving the final product a chewy texture.
What Is Gluten?
Gluten is a protein in wheat, rye, and barley that is commonly found in bread, beer, pasta, and a wide range of other processed foods containing these grains.
For about 1% of the population, eating gluten causes celiac disease, an intestinal condition characterized by the inability to absorb nutrients from food.
Celiac disease is diagnosed through blood and bowel tests, but there are no good tests to determine non-celiac gluten sensitivity, and there has been considerable debate about whether the condition even exists.
Celiac disease is an autoimmune disorder triggered by eating gluten or related proteins in rye and barley. In susceptible people, the proteins cause the body’s immune system to attack cells in the intestine called villi. The disease can disrupt nutrient absorption and lead to diarrhea, chronic abdominal pain, anemia, a rash and other symptoms. About one in 130 Americans has the disease, although many remain undiagnosed.
I can't seem to find any studies of why gluten is good for you. I did stumble upon Mark's Daily Apple's blog on the positive and negative of gluten. I advise you all to read his blog:
Tale of two gluten studies
There is also a study on Osteoporosis and Gluten Sensitivity: Check out this video:
Maybe Gluten-Free diet isn't just for people who have Celiac disease....
Remember this: Just because it is Gluten Free doesn't mean you can eat all you want. Everything is in moderation.