The present invention relates to an improved method for detoxifying gluten proteins from cereal grains which makes it possible to obtain detoxified flours with a reduction of the antigenicity of the toxic epitopes of the gluten proteins by up to a range between 0 and 20 ppm and such that they can be advantageously used for the preparation of food products (e.g. bakery products, pasta or dairy products) having a manifest preventive and/or therapeutic effect for gut dysbiosis caused by bacterial or viral infective agents or by pathologies with a strong inflammatory or autoimmune component such as celiac disease, ulcerative colitis, Crohn's disease and irritable intestine syndrome.