Vitamin D levels in people with irritable bowel syndrome

IBS patients may benefit from screening for vitamin D insufficiency and possible supplementation

Irritable bowel syndrome (IBS) affects between 10 and 15% of the population worldwide. IBS is a chronic disorder that affects the large intestine and causes an array of digestive symptoms, including constipation, diarrhoea, gas, bloating, and abdominal cramping.

Its causes are poorly understood, but the intestinal microbiota is thought to play a role. Conventional treatment for IBS focuses on symptom management. Success is limited, and this approach may not be effective for long-term management of the condition.

A number of studies have pointed to probiotics as a possible treatment for the underlying causes of IBS. In addition, vitamin D deficiency has been connected to the pathophysiology of other gastrointestinal diseases, including inflammatory bowel disease and colon cancer. Until recently, no trials had studied the link between vitamin D levels and IBS.

A 2015 randomised, double-blind, placebo-controlled pilot trial sought to clarify that link. The study included 51 participants with IBS, who were assigned to one of three groups: placebo, vitamin D (3000IU) or vitamin D (3000IU) plus probiotics (2.5×1010 of a combination of Lactobacillus acidophilus, Bifidobacterium bifidum and Bifidobacterium animalis). The intervention lasted 12 weeks.

Although the interventions did not significantly improve participants’ symptoms in this trial, the study did provide useful information for those suffering from IBS or practitioners treating people with IBS. At baseline, the majority of participants had low/deficient levels of vitamin D, suggesting that vitamin D deficiency is a serious concern in IBS.

In addition, those with low vitamin D levels had lower quality of life scores than their counterparts who had adequate levels (p<0.05). Thus, bringing vitamin D levels into balance may improve symptoms associated with this condition.

The study’s authors conclude that IBS patients may benefit from screening for vitamin D insufficiency and possible supplementation, but note that larger trials are needed to verify these findings.