IBS and vitamin D

What is Irritable Bowel Syndrome (IBS)?

As noted by Patel & Shackelford (2021), IBS is a chronic functional gastrointestinal disorder characterized by abdominal pain or discomfort, and disordered bowel habits. These typically present as constipation, diarrhoea, or a mix of constipation and diarrhoea, along with other complaints such as bloating, and distention brought on by food intake.

Prevalence of IBS

IBS is one of the most diagnosed gastrointestinal diseases in the UK; it is estimated that 10-15% of UK population suffers from this complaint. Those affected often experience problems with motility and visceral sensation (Patel & Shackelford 2021) such as abdominal pain and spasm.

IBS aetiology

The aetiology of IBS is broad and not clearly understood; in their review Chey et al (2015) suggest that factors commonly contributing to IBS include altered gut immune activation, increased intestinal permeability, social and psychological behaviour and altered gut microbiome composition. Other factors contributing to IBS include antibiotics, gastrointestinal infections and food intolerances such as gluten sensitivity (Cha et al 2020) or lactose intolerance, which can manifest as IBS (Deng et al 2015).

Management of IBS

The management of IBS is unique to everyone and depends on biochemical, physiological, emotional, genetic, dietary, environmental, and other factors.

As commented by Patel & Shackelford (2021), highly fermentable carbohydrates known as FODMAPs (e.g. wheat products, onions, fruits, vegetables, sorbitol, and some dairy) can be associated with increased gastrointestinal symptoms in some IBS patients. However, as commented by Zanwar et al (2016), intensive restriction of FODMAPs and wheat products could have long-term negative consequences due to its impact on the intestinal microbiota.

                 Vitamin D & IBS

IBS is a state of chronic low-grade mucosal inflammation (caused by activated mast cells, T lymphocytes, and proinflammatory cytokines) that contribute to increased gut hypersensitivity and perception of abdominal pain (El Amrousy et al 2018). Vitamin D, by inhibiting expression and secretion of a broad range of inflammatory mediators (Li et al 2015), has been shown to help to reduce the state of low-grade mucosal inflammation and altered immunity in IBS patients (Coussens et al 2014).

Furthermore, as vitamin D receptors are expressed in the gut, vitamin D can affect IBS symptoms via improved gut function and motility. Vitamin D receptors are linked to the activation of serotonin synthesis (Patrick & Ames 2014), which is one of the most abundant molecules in the gastrointestinal tract, as it plays a crucial role in the regulation of gastrointestinal motility and visceral sensitivity (Cirillo et al 2011).

A small randomised controlled study by El Amrousy et al (2018), involving 112 adolescents with IBS and vitamin D deficiency, has shown that the group receiving 2000 iu of oral vitamin D3 daily for 6 months presented significant improvement in their IBS symptoms, compared to the IBS placebo group.

The authors concluded that vitamin D supplementation can be effective in treating IBS symptoms in individuals with vitamin D deficiency.

References available on request.


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