Gut health is a common denominator with most of my clients and this being summer, I found a recent study that looks at the sunshine Vitamin (vit D) and gut permeability very interesting indeed, especially for those diagnosed with Crohn’s Disease.

Of course summer is the one season where I’m usually less concerned with my clients’ Vitamin D levels.  Most people know that we actually get our vitamin D from exposure to sunlight.  It’s why we in the northern hemisphere can be deficient in the months November through to April.  A lack of vitamin D can cause Rickets in children and Osteomalacia in adults. But it’s not all about bones.

There has been an explosion of research recently, because the vitamin D receptor – located in the nucleus of a variety of cells – has been discovered to play a crucial role in our innate immune response, and more than 36 types of tissue have been identified as having a vitamin D receptor (VDR). [1] Clearly vitamin D has a multitude of roles.  According to a 2010 analysis, the VDR affects 229 genes, many of which have long been associated with autoimmune diseases like Multiple Sclerosis, Type 1 Diabetes and Crohn’s Disease (an autoimmune inflammatory bowel disease).

So, what of my interesting study on Vitamin D and Inflammatory Bowel Disease (IBD)?

A research paper published in the United European Gastroenterology Journal showed that if you are experiencing a period of remission with Crohn’s Disease, Vitamin D confers additional benefit in restoring/maintaining appropriate gut permeability.[2]

Increased intestinal permeability, a measure of gut leakiness, is a feature of gut inflammation and has been shown to predict and precede clinical relapse in Crohn’s. In this small study – some 27 people were involved and in remission at the time of the treatment, using oral supplementation, with either 2000 iu of vitamin D or a placebo, administered for 90 days. They found that patients treated with vitamin D were more likely to maintain their intestinal permeability, whereas this deteriorated in the placebo group.

In addition, patients with the highest blood levels of vitamin D had signs of reduced inflammation, and these patients also reported better quality of life. Vitamin D could also positively influence the commensal bacteria residing in the colon through regulation of anti-microbial peptides.

So it seems that the Vitamin D Receptor in the gut has important roles to play in the management of our immune system, our gut microbiome and the gut barrier function in the small and large intestines.  And that during periods of inflammation (typically experienced with inflammatory bowel disease like Crohn’s) – these receptors appear to be blocked by specific molecules, making the VDR blunted to suitable agonists.

As such, determining Vitamin D status as a normal part of human health analysis these days should be looked at with greater intensity, especially if someone presents with active or quiescent IBD and that their levels of vit D may need to be monitored more closely and adjusted accordingly.


[1] Norman AW From vitamin D to hormone D: fundamentals of the vitamin D endocrine system essential for good health. Am J Clin Nutr. 2008;88:491S-499S.

[2] T. Raftery, A. R. Martineau, C. L. Greiller, S. Ghosh, D. McNamara, K. Bennett, J. Meddings, M. O’Sullivan. Effects of vitamin D supplementation on intestinal permeability, cathelicidin and disease markers in Crohn’s disease: Results from a randomised double-blind placebo-controlled study. United European Gastroenterology Journal, 2015; 3 (3): 29