Dag Tveiten

Mr. Dag Tveiten


Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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23 September 2021 in Journal of Clinical Medicine
Verified
Journal Article
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Lucyna OstrowskaLucyna Ostrowska
Lucyna Ostrowska
DWDiana Wasiluk
Diana Wasiluk
CLCamille F. J. Lieners
Camille F. J. Lieners
MGMirosława Gałęcka
Mirosława Gałęcka
ABAnna Bartnicka
Anna Bartnicka
DTDag Tveiten
Dag Tveiten
Irritable bowel syndrome (IBS) is a chronic disease with recurrent abdominal pain, disturbed bowel emptying, and changes in stool consistency. We compared the effectiveness of three different dietary treatment plans (G1-FM-low FODMAP diet, G2-IP IgG based elimination-rotation-diet, and as control group, the G3-K control diet recommended by an attending gastroenterologist) in treating patients diagnosed with mixed irritable bowel syndrome. A total of seventy-three female patients diagnosed with a mixed form of irritable bowel syndrome (IBS-M) were enrolled in the study. The diet of each patient in Group 1 (G1-FM) and 2 (G2-IP) was determined individually during a meeting with a dietitian. Patients from Group 3 (G3-K) received nutrition advice from a gastroenterologist. Significant differences in the reduction of IBS symptoms were found between the groups. IBS symptoms as well as comorbid symptoms significantly improved or disappeared completely in the G2-IP group (idiopathic abdominal pain, p < 0.001; abdominal pain after a meal, p < 0.001; abdominal pain during defecation, p = 0.008), while in the G1-FM group, some of the IBS symptoms significantly improved (mucus in stool, p = 0.031; bloating, p < 0.001). In group G3-K no significant improvement was seen. Based on the results of this open-label study, it was concluded that various dietary interventions in the treatment of IBS-M patients do not uniformly affect the course and outcomes of disease management. Rotation diets based on IgG show significantly better results compared to other diets.

14 December 2016 in Current Pharmaceutical Design
Verified
Journal Article
Closed access
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ESEmily G. Severance
Emily G. Severance
DTDag Tveiten
Dag Tveiten
LLLief H. Lindström
Lief H. Lindström
RYRobert H. Yolken
Robert H. Yolken
KRKarl L. Reichelt
Karl L. Reichelt
Background: Autoimmune phenotypes are prevalent in major psychiatric disorders. Disequilibria of cellular processes occurring in the gastrointestinal (GI) tract likely contribute to immune dysfunction in psychiatric disorders. As the venue of a complex community of resident microbes, the gut in a homeostatic state equates with a functional digestive system, cellular barrier stability and properly regulated recognition of self and non-self antigens. When gut processes become disrupted as a result of environmental or genetic factors, autoimmunity may ensue. Methods: Here, we review the issues pertinent to autoimmunity and the microbiome in psychiatric disorders and show that many of the reported immune risk factors for the development of these brain disorders are in fact related and consistent with dysfunctions occurring in the gut. We review the few human microbiome studies that have been done in people with psychiatric disorders and supplement this information with mechanistic data gleaned from experimental rodent studies. Results: These investigations demonstrate changes in behavior and brain biochemistry directly attributable to alterations in the gut microbiome. We present a model by which autoantigens are produced by extrinsicallyderived food and microbial factors bound to intrinsic components of the gut including receptors present in the enteric nervous system. Conclusion: This new focus on examining activities outside of the CNS for relevance to the etiology and pathophysiology of psychiatric disorders may require new modalities or a re-evaluation of pharmaceutical targets found in peripheral systems.

30 January 2018 in BMC Gastroenterology
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Journal Article
Open access
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AKAnne Stine Kvehaugen
Anne Stine Kvehaugen
DTDag Tveiten
Dag Tveiten
PFPer G. Farup
Per G. Farup
Serum IgG and IgA food antibodies have been used for dietary advice to subjects with gastrointestinal symptoms and perceived food intolerance, but the role of these antibodies in mediating intolerance is controversial. The present study investigated associations between perceived gastrointestinal intolerance to milk-or wheat and the corresponding s-IgG and s-IgA food antibodies in subjects with morbid obesity. Subjects with morbid obesity (BMI ≥ 40 kg/m2 or ≥35 kg/m2 with obesity-related complications) were included. Irritable Bowel Syndrome (IBS) was diagnosed based on the Rome III criteria. Severity of specific gastrointestinal symptoms were measured with the Gastrointestinal Symptom Rating Scale (GSRS)-IBS. S-IgG against cow’s milk, cheese, wheat and gluten, and s-IgA against casein and gliadin were measured. Ninety-seven subjects (80 females) with mean age 45 (SD 8.4) years were included, 70 had gastrointestinal complaints, 25 had IBS, and 22 and 20 reported milk- and wheat- intolerance respectively. There were no significant differences in serum concentrations or proportions of subjects above defined cut-off values for the antibodies between subjects with and without gastrointestinal complaints. In the group with gastrointestinal complaints, no significant differences were found between subjects with and without perceived food intolerance. Except for a significant correlation between IgG against cheese and GSRS-diarrhea (Rho: -0.25, P = 0.04), no significant correlations were found between the antibodies and type or degree of gastrointestinal symptoms, including IBS. The study showed no associations between perceived milk or wheat intolerance and the corresponding s-IgG and s-IgA food antibodies in subjects with morbid obesity.

28 June 2021 in Tidsskrift for Den norske legeforening
Verified
Journal Article
Closed access
PDF file
DTDag Tveiten
Dag Tveiten
JNJon Norseth
Jon Norseth
CSClemens Von Schacky
Clemens Von Schacky
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