Studies have shown that the protein matrix referred to as gluten, found in wheat and related grains, can induce changes to the bowel epithelial (lining) cells and change the physical makeup and absorption system of the small intestines. This can result in such things as: leaky gut, disaccharidase deficiency, malabsorption, lactose intolerance, and cross-reactivity food sensitivities. Celiac disease is one of the more serious results, in certain individuals, in which there is the induction of an autoimmune cascade leading to severe damage to the small intestine architecture. It's believed that in the more serious reactions to gluten there is a genetic predisposition. But this doesn't account for all cases, especially when we consider the high rates of non-celiac gluten sensitivity. In this case, environmental factors such as excess stress, infection, or medication side-effects can induce gluten intolerance.
The damaging effects of gluten can lead to a person being allergic or intolerant to other foods, making the situation even more complicated. Commonly dairy intolerance can result from the damaging effects of gluten. It's also been observed that gluten can induce intolerance to a long list of foods, including: chocolate, coffee, rice, oats, buckwheat, sorghum, potato, quinoa, millet, soy and tapioca. You'll note that many of these items are foods often used in place of wheat when on a gluten-free diet.
The question is often raised as to why all of a sudden is everyone intolerant to wheat and gluten? Like a lot of medical mysteries this one is still being sought after. Some of the top theories include the hybridization of wheat into a specific strain of high gluten hard winter wheat that dominates flour production and the food industry in the Western world. Perhaps we are weakening as a species. The amount of grains consumed in the diet today is unprecedented in human history. Historically as grains became a human staple, they were processed in such a way to assist digestibility and nutritional content. Today those practices are largely ignored. They included fermentation, soaking and sprouting.
More recently the theory of toxicity has emerged. I recently read of research analyses that have correlated the use of herbicides such as Round Up (glyphosate) with the increase in gluten sensitivity. Glyphosate has been increasingly used to kill wheat crops near harvest to speed up the time it takes to get the wheat off the field and into your food. The glyphosate residue may shield the gluten from being properly digested then induce it's deleterious effects. If this is indeed the case, one can avoid this herbicide by eating only organic wheat. (note: glyphosate is widely use on corn, soy, and other crops and research is increasingly showing it causes harm)
Whether you are susceptible to Celiac disease or gluten intolerance, there are other benefits of reducing your intake of wheat, and all grains for that matter. Excess consumption of grains is associated with weight gain, cardiovascular disease and diabetes. Often cutting down on gluten forces one to increase the diversity in his or her diet. Hopefully that means more nutrient-rich vegetables, fruits, beans and legumes, and lean meats.
There are lab tests available to test your tolerance or lack thereof to gluten. In addition, specialty labs have developed ways to test for sensitivity to other foods. Through this process you will likely find a new level of wellness and diversity in your diet.