Nutritional status and immunocompetence in eating disorders

Abstract

Eating disorders (ED), such as anorexia nervosa (AN) and bulimia nervosa (BN), are characterized by aberrant eating behaviours with a severe impact on their nutritional status. The undernourished state of AN patients is patent, while BN patients malnutrition is more a subclinical state. Overall, the effects on the immune system are characterized by leukopenia with relative lymphocytosis that does not prevent a decrease in the absolute number of T lymphocytes. There is not a general agreement on the magnitude of the alteration of cell-mediated immune function, including activities such as lymphoproliferation, cytokine production, antigen presentation or recall responses, which have shown inconsistent results in different studies. In this regard, it is important to pay attention to individual characteristics such as duration of the disease, ED subtype, compensatory mechanisms, psychiatric comorbidities’including anxiety, depression and stress and drug prescriptions, which have an influence on the immunological parameters. On the other hand, a surprisingly low incidence of infection has been reported frequently in AN patients; however, this is generally regarded as a perceived lack of infection symptoms due to an impaired capacity to mount an acute-phase response against infectious agents. Changes in the interactions between the endocrine, central nervous and immune systems are considered relevant to understand the adaptive mechanisms triggered in these syndromes. The role of cytokines and several hormones are reviewed for their possible implication in the pathogenesis and maintenance of the disease.