Adherence may be difficult due to the large variety of processed foods in the U.S. which contain gluten. Education is required to avoid all foods containing wheat, rye, barley (including all types of beer), and oats. Distilled alcohol beverages and wine are generally free of gluten. Patients should be counseled to avoid occult sources of gluten in foods. Gluten containing foods should be substituted for corn, rice, soy, buckwheat, beans, vegetables, fruits, nuts, tapioca flour, rice, potatoes, and lean meats. Oat consumption is controversial, with research showing that oats may provoke gluten related disorder, while other research has supported oats as generally safe to consume. It may be best to avoid oats if intolerance to oats is suspected.