Gluten-free is meaning that the food either is inherently gluten free; or does not contain an ingredient that is: 1) a gluten-containing grain (e.g., spelt wheat); 2) derived from a gluten-containing grain that has not been processed to remove gluten (e.g., wheat flour); or 3) derived from a gluten-containing grain that has been processed to remove gluten (e.g., wheat starch), if the use of that ingredient results in the presence of 20 parts per million (ppm) or more gluten in the food. Also, any unavoidable presence of gluten in the food must be less than 20 ppm.
Gluten is a protein composite found in wheat, barley, rye, and all their species and hybrids (such as spelt, kamut, and triticale.
Gluten causes health problems in sufferers of gluten-related disorders, which include coeliac disease (CD), non-celiac gluten sensitivity (NCGS), gluten ataxia, dermatitis herpetiformis (DH) and wheat allergy. In these patients, the gluten-free diet is a demonstrated effective treatment. In addition, at least in some cases, the gluten-free diet may improve gastrointestinal and/or systemic symptoms in other diseases, such as irritable bowel syndrome, rheumatoid arthritis, multiple sclerosis or HIV enteropathy, among others.
Gluten proteins have low nutritional and biological value and are not essential in the diet. However, an unbalanced selection of food and an incorrect choice of commercially prepared gluten-free replacement products, which are poorer nutritional quality and have greater lipid/carbohydrate content compared to the gluten-containing counterparts, may lead to nutritional deficiencies. These nutritional complications can be prevented by a correct dietary education. Gluten free-diet must be mainly based on naturally gluten-free foods, which are more equilibrate in micro and macronutrients, such as meat, fish, eggs, legumes, nuts, fruits, vegetables, potatoes, rice, maize. It is advisable to choose commercially prepared gluten-free replacement products that are enriched or fortified with vitamins and minerals.
The inclusion of oats in gluten-free diet remains controversial. Avenin present in oats may be also toxic for coeliac people. Its toxicity depends on the cultivar consumed. Furthermore, oats are frequently cross-contaminated with gluten-containing cereals.