The Effect of a Gluten-Free Diet on Vitamin D Metabolism in Celiac Disease: The State of the Art.

Celiac disease is a chronic autoimmune disorder involving the small intestine, characterized by villous atrophy, crypt hyperplasia and an increase in intraepithelial lymphocytes. Due to both calcium malabsorption and immune activation, a high prevalence of bone mass derangement is evident in this condition, regardless of the presence of overt malabsorption. Alterations of mineral metabolism are also frequently described, and in this review, the modifications of serum levels of vitamin D are analyzed, according to the available literature on this topic. In untreated patients, secondary hyperparathyroidism is responsible for the hyperconversion of 25-vitamin D into 1,25-vitamin D making mandatory the determination of serum levels of both vitamin metabolites to avoid a wrong diagnosis of vitamin D deficit. A gluten-free diet allows for a normalization of bone and mineral metabolism, reverting these abnormalities and raising some doubts on the need for vitamin supplementation in all the patients. Data available do not support this wide indication, and a complete evaluation of bone and mineral metabolism should be performed to select patients who need this therapeutic approach.

Pathophysiology and therapeutic management of anemia in gastrointestinal disorders.

INTRODUCTION: Anemia is a common complication of gastrointestinal (GI) disorders, with a prevalence up to 60% in celiac disease (CeD) and inflammatory bowel disease (IBD). Iron deficiency anemia (IDA) is the most prevalent form of anemia in these conditions, but chronic inflammation and vitamin B12 deficiency represent other common contributing mechanisms, especially in IBD. AREAS COVERED: We discuss the pathogenesis of anemia in various medical GI disorders, the sometime problematic distinction between IDA, anemia of inflammation (AI) and the association of the two, and therapeutic and preventive measures that can be useful for the management of anemia in GI disorders. Unfortunately, with the exception of IDA and AI in IBD, large RCT concerning the treatment of anemia in GI disorders are lacking. EXPERT OPINION: Anemia management strategies in GI disorders are outlined, with a focus on the main prevention, diagnostic, and therapeutic measures. Specific problems and situations such as the role of gluten-free diet for IDA treatment in CeD, the choice between oral and parenteral supplementation of iron or vitamin B12 in carential anemias, the use of endoscopic procedures to stop bleeding in intestinal angiodysplasia and preventive/treatment strategies for NSAID-associated GI bleeding are discussed.

Impaired Quality of Life in Patients with Autoimmune Atrophic Gastritis.

BACKGROUND: Autoimmune atrophic gastritis (AAG) leads to vitamin B12 deficiency that may manifest with neuropsychiatric disorders, such as emotional instability, cognitive deficits, depression, and personality changes. AIMS: To evaluate the quality of life (QoL) in patients with AAG and the interplay between QoL, psychopathological symptoms, and demographic factors. METHODS: This is an observational, cross-sectional study including 102 patients with AAG (mean age 62 ± 13 years), 100 with functional gastrointestinal disorders (mean age 38.3 ± 17 years), 100 with other chronic organic gastrointestinal diseases (mean age 50.9 ± 21.4 years), and 100 healthy controls (mean age 37.5 ± 18.9 years). The 36-Item Short Form Health Survey questionnaire (SF-36) and the General Health Questionnaire-12 were administered. The results of the scales were compared among the study groups. Linear regression analyses were fitted to identify independent predictors of QoL in AAG patients. RESULTS: QoL was significantly different among the four groups in all subdomains. In particular, the AAG group was significantly (P < 0.01) more impaired than the functional gastrointestinal disorder group in the physical functioning and it was significantly more impaired than the control group in all the quality of life subdomains with exception of vitality. Vitamin B12 serum level was a significant (P < 0.04) independent predictor of physical functioning. CONCLUSIONS: Patients with AAG have a decreased QoL compared to healthy controls, but in line with that of patients with organic gastrointestinal disorders. Physical component is responsible for worsening QoL. Vitamin B12 supplementation may positively affect patient's perception of body functioning.

Autoimmune gastritis.

Autoimmune gastritis (AIG) is an increasingly prevalent, organ-specific, immune-mediated disorder characterized by the destruction of gastric parietal cells, leading to the loss of intrinsic factor and reduced acid output. These alterations result in malabsorption of iron, vitamin B12 (pernicious anaemia) and potentially other micronutrients. For several years, most studies have focused on pernicious anaemia only, generating confusion between the two entities. In AIG, the gastric proton pump, H+/K+ ATPase, is the major autoantigen recognized by autoreactive T cells. The T cell-dependent activation of B cells stimulates the production of anti-parietal cell antibodies, the serological hallmark of AIG. The role of Helicobacter pylori infection in activating or favouring the autoimmune process is still uncertain. Early histopathological alterations allowing a more precise and prompt recognition have recently been described. AIG is burdened by a substantial diagnostic delay as it can present with varied clinical signs including, among others, gastrointestinal symptoms and neuropsychiatric manifestations. In advanced stages, AIG might progress to neuroendocrine tumours and gastric adenocarcinoma. Management includes early detection through a proactive case-finding strategy, micronutrient supplementation and endoscopic surveillance. This Primer comprehensively describes the most important insights regarding the epidemiology, pathophysiology, diagnosis and management of AIG, focusing on the most controversial, outstanding issues and future directions.