According to Wikipedia, 0.5 to 1.0% of Americans are sensitive to gluten due to celiac disease or also known as the gluten allergy. It is categorized as an autoimmune disease brought about by the introduction of gluten into the body and it also has been told that repeated exposure to the proteins in gluten could become more serious.

Some of the usual symptoms of gluten allergy esp. in the digestive tract are indigestion, heartburn, irritable bowel syndrome, diarrhea, bloating gas and abdominal pain. However, please note that the symptoms not only are reserved for the digestive tract. Some people who have gluten allergy could experience chronic fatigue, itchy dermatitis, severe weight loss, migraines, stress and/or depression and hives and/or swelling. Of course, conditions should vary from person to person so it’s important to speak with your doctor should you ever experienced the above-mentioned symptoms. If you’re considering a gluten-free diet then you can always have the help of the internet. You just have to search for gluten-free recipes.

Gluten is a from of protein that can be found in wheat, barley and rye. This give the elasticity and stickiness to the bread or dough and giving it a chewy feeling. Gluten may cause allergic reactions in people who are sensitive to foods that contain protein. Gluten has actually genetic derivatives of wild grass that possesses the possibility of containing some toxicity.

Gluten disease or often called Celiac disease is a result to intolerance to Gliadin which can be found in Gluten. Gliadin is an insoluble protein that may trigger a reaction in the body of certain people especially those who are intolerant to Gluten.
Celiac disease is considered a hereditary disorder of the immune system which can last throughout a person's life. If a person is sensitive to gluten it mean that he has an ongoing immune reaction to gluten in his/her diet and if he takes in food with gluten this can cause irreversible damage to the lining of his small intestine making his immune system weak
The symptoms and reactions vary from person to person and depends also on the genetic reactions to the Gluten.
If a person has gluten intolerance he should avoid all grains containing Gluten like barley, rye and wheat.
There was no major benefits of having gluten in one's diet. At least nothing was mentioned so far.