**5.1 Diet therapy: gluten-free diet**

Only effective treatment available for CD consists of following a strict GFD, excluding gluten proteins from the diet from wheat, barley, rye, and oats, as well as hybrids of these cereals such as triticale and their derivatives (starch, flour, etc.) [14]. Nevertheless, such a diet is difficult to follow due to the unintended contamination of "gluten-free" products, improper labeling, social constraints, and ubiquity of gluten proteins in raw or cooked foods and pharmaceuticals. Thus, accidental gluten encounters are likely. Most patients with CD can safely tolerate approximately 10mg of gluten cross-contamination daily. However, there is a tremendous degree of variability within this population, and some patients may have worsening histological changes with very low daily gluten exposure [1, 10].

Strict adherence to GFD leads to remission of gastrointestinal and extra-intestinal symptoms, normalization of serological tests, and recovery of the intestinal mucosa, in most cases [14]. Initiation of strict GFD generally results in a rapid improvement of clinical symptoms, while recovery of the intestinal villi requires several years of a strict GFD (around 2 years in 34% and 5 years in 66%) [44]. Therefore, it is essential that patient with CD is aware of adherence to GFD to avoid future complications.
