Abstract
Inflammatory bowel diseases (IBDs) and irritable bowel syndrome (IBS) are associated with decreased quality of life and mental health problems. Among various approaches to supportive therapy that aims to improve mental health in affected individuals, vitamin D supplementation is considered to be an effective method which may also be beneficial in alleviating the symptoms during the course of IBDs and IBS. The aim of the present study was to conduct a systematic review of the literature presenting the data regarding the influence of vitamin D supplementation on mental health in adults with inflammatory and functional bowel diseases, including IBDs and IBS. This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (Registration number CRD42020155779). A systematic search of the PubMed and Web of Science databases was performed, and the intervention studies published until September 2021 were included. The human studies eligible to be included in the review should have described any intervention involving vitamin D as a supplement in a group of adult patients suffering from IBDs and/or IBS and should have assessed any component of mental health, but studies presenting the effects of combined supplementation of multiple nutrients were excluded. After eliminating the duplicates, a total of 8514 records were screened and assessed independently by two researchers. Further evaluation was carried out on the basis of title, abstract, and full text. Finally, 10 studies (four for IBDs and six for IBS) were selected for the current systematic review, and their quality was assessed using the Newcastle–Ottawa Scale (NOS). The studies analyzed the influence of various doses of vitamin D on bowel diseases, compared the results of vitamin D supplementation with placebo, or administered specific doses of vitamin D to obtain the required level in the blood. Supplementation was performed for at least 6 weeks. The analyzed mental health outcomes mainly included disease-specific quality of life/quality of life, anxiety, and depression. The majority of studies (including high-quality ones) confirmed the positive effect of vitamin D supplementation on the mental health of IBD and IBS patients, which was proven by all research works evaluating anxiety and depression and by the majority of research works evaluating quality of life. Although the studies followed different dosage regimens and supplementation protocols, the positive influence of vitamin D on mental health was found to be consistent. The number of studies on patients suffering from ulcerative colitis and the availability of trials randomized against the placebo group was low in the current review, which is considered to be a limitation of the present study and could also reflect the final outcome of the analysis. The conducted systematic review established the positive effect of vitamin D supplementation on the mental health of IBD and IBS patients, but this result requires further investigation, particularly in relation to other mental health outcomes.
Highlights
Inflammatory bowel diseases (IBDs), including ulcerative colitis (UC) and Crohn’s disease (CD), are idiopathic intestinal disorders that are characterized by repetitive episodes of inflammation of the gastrointestinal tract, usually associated with bloody diarrhea, tenesmus, and abdominal pain, while the location of the disease and the thickness of the affected bowel wall differ in the diseased individuals [1]
IBDs exert a significant influence on the quality of life of the affected patients, which was demonstrated by a recent systematic review and meta-analyses by Knowles et al [4], who claims that the quality of life of IBD patients depends on the stage and type of disease, which is found to be lower during relapses than during remissions and lower in CD than in UC
The studies of IBD patients included in the systematic review were conducted mainly in CD patients [32,34], but one study was conducted in UC patients [35] and one in a mixed population comprising both CD and UC patients [33]
Summary
Inflammatory bowel diseases (IBDs), including ulcerative colitis (UC) and Crohn’s disease (CD), are idiopathic intestinal disorders that are characterized by repetitive episodes of inflammation of the gastrointestinal tract, usually associated with bloody diarrhea, tenesmus, and abdominal pain, while the location of the disease and the thickness of the affected bowel wall differ in the diseased individuals [1]. They are characterized by alternating periods of remissions and relapses [2] and predicting the exact course of the disease is difficult [3]. The systematic review and meta-analysis by Lee et al [12] showed that depression and anxiety levels in IBS patients are higher than the levels observed in healthy controls
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