Gluten is a protein that is found in wheat, with similar proteins being found in rye, barley and oats... You are unlikely to be able to purchase *gluten* per se but obviously you can buy wheat flour, barley flour and oatmeal. I've never heard of low-card bread - do you mean low *carb* (ie low carbohydrate) bread ? If so, then you really want to be avoiding wheat and the other flours, as they are high carbohydrate products.