Food Intake and IgA Microbiota in Anorexia Nervosa

Inclusion Criteria: * female subject, adult, affiliated to a social security system, under the care of the eating disorder department of university hospital of st Etienne * presenting a diagnosis of pure restrictive anorexia nervosa. For acute subgroup : BMI between 11 and 17.5 kg/m2, patient with a first episode of restrictive anorexia nervosa or with hyperphagic episodes. For the chronic subgroup: BMI between 11 and 17.5 kg/m2, disease evolving for more than 5 years. For Healthy volunteer: BMI between 20 and 24 kg/m², stable weight for the last 3 months, no eating disorder or history of eating disorder Exclusion Criteria: * patient does not understand French. * laxative treatment in progress or stopped for less than 15 days, * antibiotic treatment in the two months preceding inclusion, * pre-pro or symbiotic treatment in progress or in the month preceding inclusion, * patient with one of the following comorbid disorders: celiac disease, chronic inflammatory bowel disease, lactose intolerance, unstabilized hyperthyroidism, unstabilized diabetes, * subject under legal protective measures.