Gluten is the protein in breads that gives them that chewy elasticity.  When kneading bread dough, bakers stimulate the gluten molecules to get that wonderful texture.  Without that stimulation, the bread would be more tender and cake-like in texture.

Found in grains like wheat, barley, and rye, gluten is known to cause serious illness in those with Celiac Disease.  These are people who lack the ability to properly digest gluten, causing damage to the small intestines.  This can lead to nutritional defeciencies, infertility, osteoporosis, diarrhea, bloating, and lymphoma.  The good news is that when a person with this condition removes all traces of gluten from his/her diet, the intestines heal and the obvious symptoms disappear.

These days, it has become very trendy to be on a gluten free diet.  It is known that while some people do not have an intolerance to gluten, they do have a sensitivity to it, and just feel better when they remove it from their diets.  These people do not have to remove every molecule of gluten from their diets as the Celiac population does.

In the last few months the American Heart Association revealed the results of an interesting study, done by Harvard  scientists, showing that among their 200,000 subjects those who ate the most gluten in their diets had a 13% lower risk of developing Type II diabetes.  It is speculated that being on a gluten free diet robbed the subjects of protective cereal fiber, leading to their increased risk.