The gluten-free diet consists of strictly eliminating from the diet all products that contain or are cooked with wheat, rye, barley and oats, or any of their varieties and hybrids (spelt, spelt, kamut, triticale…), and derived products, avoiding inadvertent contaminations and all types of dietary transgressions. Gluten is not indispensable for human beings. It is a mixture of proteins of low nutritional and biological value, deficient in essential amino acids, so from a nutritional point of view its exclusion from the diet does not represent any problem. The gluten-free diet is a safe diet, which does not cause any negative side effects, and is normally balanced. Only celiacs and people sensitive to non-coeliac gluten experience symptoms and various health disorders if they do not maintain the gluten-free diet strictly and for life.
The gluten-free diet should be based primarily on natural gluten-free products, which have a more balanced composition of micro and macronutrients, such as meat, fish, eggs, milk and dairy products, legumes, nuts, fruits, vegetables, potatoes, rice, corn and pseudocereals. If specific coeliac preparations are consumed commercially, the best choice is those enriched or fortified with vitamins and minerals. A healthy alternative to these commercial products is the production of pseudocereal flours (certified without gluten contamination), such as quinoa, amaranth, buckwheat and other minor cereals, which have a high nutritional and biological value, superior to those of gluten-containing cereals. The different varieties of pure oats (without gluten contamination of other cereals) have different degrees of toxicity.
As of 2018, Except in Brazil, it is not mandatory in any country in the world to label products as “Gluten-Free” or to declare the presence of traces of gluten, so simply reading the list of ingredients does not allow one to know if a product is safe. Other unsuspected sources of gluten can be medicines, supplements and food supplements, as well as adhesive bandages, plasters, feed and food for farm animals and pets, all kinds of cosmetic and personal care products, shampoos for dogs, modeling paste for children (such as Play-Doh), among others. These products may be the cause of inadvertent gluten contamination, as they may reach the mouth directly, or indirectly through the remains left on the hands when handled.
The gluten-free diet is a healthy diet because it is very varied and requires more attention to the composition and preparation of food, increasing the consumption of all types of vegetables and fruits, as well as natural foods, not frozen or processed, thus reducing the consumption of additives and sodium. However, some patients focus only on the elimination of gluten from the diet and downplay the importance of proper diet planning. An unbalanced selection of foods and an incorrect choice of alternative commercial gluten-free products specific to coeliacs (those traditionally made with wheat flour, such as breads, biscuits, etc.), can lead to certain nutritional deficiencies. In general, these alternative products are not usually fortified compared to their gluten equivalents, so there may be a lower intake of iron and B vitamins; they also contain higher amounts of lipids and carbohydrates, although since 2017 there is a trend of nutritional improvement with increased levels of fiber and decreased sugar content. These products are especially overconsumed by children, which also leads to a decrease in the consumption of other, healthier foods. These nutritional imbalances can be prevented with proper dietary education. In addition, certain complications of celiac disease, which sometimes do not subside despite a gluten-free diet, can lead to overweight or obesity.
The gluten-free diet is the only currently available treatment for celiac disease, which must be followed strictly and for life, without transgressions, in order to achieve a sustained and effective improvement, avoiding and/or significantly diminishing the appearance of numerous diseases and associated complications both digestive and extradigestive, since celiac disease can damage virtually any organ or tissue. Although there is a “permanent intolerance” to gluten, it is not a simple food intolerance, much less an allergy. It is a chronic, multi-organ autoimmune process that, if left untreated, can lead to very serious health complications, including various types of cancer (both of the digestive tract, with a 60% increased risk, and of other organs), neurological and psychiatric disorders (known as “neurogluten”), other autoimmune diseases, cardiovascular diseases, and osteoporosis, among others. The mean for complete bowel recovery usually ranges from two to five years. In addition, the gluten-free diet has been shown to be an effective treatment for all other gluten-related disorders, including non-coeliac gluten sensitivity, gluten ataxia, dermatitis herpetiformis, and wheat allergy. The mean for complete bowel recovery is usually two to five years.
In people with gluten-related neurological disorders, the regeneration of the nervous system once the diet is initiated is slow and sometimes incomplete, mainly when the diagnosis is delayed, but prevents the progression of neurological damage. Minimal amounts of gluten, including those present in most products labeled “Gluten-Free,” may be sufficient to keep the immune system response responsible for the neuronal lesion activated in a portion of patients.
Other diseases in which improvement of both gastrointestinal and systemic symptoms with the gluten-free diet has been documented in at least part of the patients include irritable bowel syndrome, type 1 diabetes mellitus, thyroiditis, systemic lupus erythematosus, rheumatoid arthritis, psoriasis, multiple sclerosis, Tourette syndrome and HIV enteropathy, among others. There is no experimental evidence that the gluten-free diet is a healthier option for the general population.
Adherence to the diet in coeliacs is much worse than what was traditionally considered by scientists and specialists. Current studies show that approximately 80% of coeliacs continue to have intestinal injury, despite continued treatment with the gluten-free diet. The main cause of this lack of recovery is the inadvertent intake of gluten, mainly due to cross-contamination. A 2018 meta-analysis concludes that most celiacs, especially adults but also children, continue to ingest gluten regularly, involuntarily, despite being on a gluten-free diet. People with poor basic education and low understanding of how to follow a gluten-free diet often believe that they are strictly following the diet, but are making frequent mistakes. A common problem is the patient’s lack of awareness of avoiding gluten contamination in food preparation and other common sources of gluten, such as oatmeal, communion wafers, malted beverages, medications, processed foods, restaurant meals, and social events. Eating out poses a great risk since despite offering a “gluten-free” menu, many establishments (restaurants, school canteens, etc.) do not strictly follow the rules to avoid cross-contamination. If gluten suppression is not complete and maintained for life, intestinal mucosal damage, immune activation, and the risk of developing very serious health complications persist. The strict gluten-free diet appears to have a protective role against the development of cancers in celiacs and is the only option to prevent certain rare, highly aggressive cancers. However, delay in the diagnosis of celiac disease increases the likelihood of developing malignancy. The protective effect is most effective when the gluten-free diet is initiated at an early age, especially during the first year of life.
None of the methods used to date (2018) to evaluate strict adherence to the gluten-free diet is objective or reliable: patient questionnaires, symptom assessment, determination of celiac-specific antibodies, and findings in duodenal biopsies. Neither the absence of digestive symptoms nor the negativity of antibodies guarantee recovery of intestinal mucosa, which is complicated by biopsies. This is due to the fact that lesions of the intestine usually consist of minimal changes, without atrophy of the villi, which are difficult to identify. A new method based on the detection of gluten in samples of urine or feces for professional use has been available since 2017 and, since January 2018, in a version for domestic use, which has demonstrated its effectiveness in scientific studies to control compliance with the diet and detect trace contamination.