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Cognitive impairment in coeliac disease improves on a gluten-free diet and correlates with histological and serological indices of disease severity.
Lichtwark, IT, Newnham, ED, Robinson, SR, Shepherd, SJ, Hosking, P, Gibson, PR, Yelland, GW
Alimentary pharmacology & therapeutics. 2014;40(2):160-70
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Plain language summary
Coeliac disease (CD) is an inflammatory autoimmune disorder caused by the ingestion of gluten. While CD is known to primarily affect the bowel, there is reported evidence of potential neurological side effects. Cognition may be impaired in undiagnosed CD patients because of nutrient deficiencies, systemic inflammation and changes in the gut microbiome. CD patients often report a mild cognitive impairment, brain fog, characterised by difficulty concentrating, short-term memory and confusion. The aim of this study was to investigate the relationship between gut mucosal healing and cognitive function in eleven patients recently diagnosed with CD commencing a strict gluten-free diet. The findings of this study showed that in newly diagnosed CD patients, cognitive functioning improved with a gluten-free diet and was correlated with mucosal healing. Based on this study, the authors conclude that cognition is impaired in people with untreated coeliac disease and may affect the performance of everyday tasks. This finding also introduces the possibility of using cognitive tests to provide a marker of intestinal healing.
Abstract
BACKGROUND Mild impairments of cognition or 'Brain fog' are often reported by patients with coeliac disease but the nature of these impairments has not been systematically investigated. AIM: This longitudinal pilot study investigated relationships between cognitive function and mucosal healing in people with newly diagnosed coeliac disease commencing a gluten-free diet. METHODS Eleven patients (8 females, 3 males), mean age 30 (range 22-39) years, were tested with a battery of cognitive tests at weeks 0, 12 and 52. Information processing efficacy, memory, visuospatial ability, motoric function and attention were tested. Small bowel biopsies were collected via routine gastroscopy at weeks 12 and 52 and were compared to baseline Marsh scores. Cognitive performance was compared to serum concentrations of tissue transglutaminase antibodies, biopsy outcomes and other biological markers. RESULTS All patients had excellent adherence to the diet. Marsh scores improved significantly (P = 0.001, Friedman's test) and tissue transglutaminase antibody concentrations decreased from a mean of 58.4 at baseline to 16.8 U/mL at week 52 (P = 0.025). Four of the cognitive tests assessing verbal fluency, attention and motoric function showed significant improvement over the 12 months and strongly correlated with the Marsh scores and tissue transglutaminase antibody levels (r = 0.377-0.735; all P < 0.05). However, no meaningful patterns of correlations were found for nutritional or biochemical markers, or markers of intestinal permeability. CONCLUSIONS In newly diagnosed coeliac disease, cognitive performance improves with adherence to the gluten-free diet in parallel to mucosal healing. Suboptimal levels of cognition in untreated coeliac disease may affect the performance of everyday tasks.
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[Nursing and organizational development].
Donnenberg, OH, Locher, K
Tijdschrift voor ziekenverpleging. 1986;39(1):18-22
Plain language summary
The relationship between gluten exposure and diarrhoea-predominant irritable bowel syndrome (IBS-D) is not well understood. Non-celiac IBS-D patients who are positive for HLA-DQ2/8 genes associated with CD can show symptom improvement on a gluten-free diet (GFD). The aim of this 4-week parallel randomized controlled clinical trial in HLA-DQ2/8 positive and negative patients with IBS-D was to assess the effects of a gluten-containing diet (GCD) compared to a GFD on bowel function, gut transit, small bowel and colonic barrier functions. 45 patients were recruited from the Mayo clinic’s database of IBS suffers, and invited to participate. Patients with diagnosed CD were excluded. 22 patients were placed on the GCD (11 HLA-DQ2/8–negative and 11 HLA-DQ2/8–positive) and 23 on the GFD (12 HLA-DQ2/8−negative and 11 HLA-DQ2/8–positive). All meals and snacks were ingested or prepared in the Mayo Clinic. Patients were advised to eat only the foods provided by the study dieticians. Gluten-free and gluten-containing meals were prepared using the same macronutrient content (20% protein, 30% fat, 50% carb). Compliance to the diet was assessed by direct questioning by the dietitians and reported to be excellent. All patients were ingesting gluten in their diet prior to starting the study. At 4-weeks, a statistically significant decrease in stool frequency of subjects on GFD compared to subjects on GCD was seen. This effect was more pronounced in subjects who were HLA-DQ2 or 8 positive. There was no significant dietary effect on daily stool form, ease of passage or gastric emptying. The GCD was associated with higher small bowel permeability and lactulose:mannitol ratio. Small bowel permeability was greater in HLA-DQ2/8–positive than negative patients. No significant differences in colonic permeability were observed. The author concludes that this study provides mechanistic explanations for the observation that gluten withdrawal may improve patient symptoms in IBS. The data also partially explains that the biological effects of gluten were associated with HLA-DQ2 or 8 genotype. The relationship of dietary factors, innate and adaptive immune responses and mucosal interactions in IBS-D deserve further study. Further clinical studies evaluating the effects of gluten withdrawal in patients with IBS-D are needed.