Gluten is a family of proteins found in some grains, including wheat, rye and barley. For more than 90% of the population, avoiding gluten is not only unnecessary but may be a mistake, since gluten has been shown to improve immune function, and certain starches found in wheat and other grains improve our gut health. More importantly, consuming whole grains is associated with a reduced risk of coronary heart disease, cancer, diabetes, and obesity.
About 1% of the general population has celiac disease, a genetic condition in which eating gluten can cause an autoimmune response that leads to damage of the small intestine. People with celiac disease should avoid gluten and any food that contains it.
An additional 5-7% of people have non-celiac gluten sensitivity, a milder form of gluten intolerance that can cause a variety of symptoms including intestinal bloating and discomfort, but does not cause damage the small intestine. Even rarer is a wheat allergy, which isn’t directly related to gluten and therefore typically allows for the consumption of gluten-containing grains barley and rye, as well as gluten-free grains like oats, rice, corn, quinoa, amaranth, and so on.
All told, less than 10% of the general population has an issue with gluten and/or wheat, while the vast majority (>90%) actually benefit from whole grains, including wheat, and are advised to include them in their diet on a regular basis to help optimize health.