In a new study entitled “The non dietary determinants of vitamin D status in pediatric inflammatory bowel disease,” authors investigated which mechanisms underlie the vitamin D deficiency commonly diagnosed among patients with inflammatory bowel disease (IBD). The study was published in the journal Nutrition.

In this study, researchers investigated the mechanisms behind vitamin D deficiency in patients with inflammatory bowel disease (IBD). Previous results suggested that serum albumin (this parameter is a marker for protein-losing enteropathy, a condition characterized by severe loss of serum proteins into the intestine, and liver function) was the main contributor to vitamin D deficiency in IBD patients. To determine the underlying mechanisms for the lack of vitamin D and test the suggested hypothesis, researchers performed a retrospective study with 59 pediatric patients with IBD and with 116 healthy controls. The authors focused on a crucial step in vitamin D metabolism, the generation of an important intermediate, the (25[OH]D), and whether impairing this step leads to vitamin D deficiency.

The team found that pediatric patients with IBD had a higher prevalence of vitamin D deficiency, specifically, 42.4% versus 26.7%, respectively. Additionally, IBD patients exhibited higher levels of alanine transaminase (ALT), a specific biomarker of liver damage. However, the team found no association between vitamin D and markers of hepatic inflammation in IBD patients. Notably, authors found that it is the level of intestinal inflammation that constitutes the primary determinant of vitamin D status at the intestinal level, and not how much vitamin D bound to albumin is lost in the gut. (Intestinal inflammation was measured by the erythrocyte sedimentation rate, ESR, a test where researchers measured the rate at which red blood cells sediment in a period of one hour and is a non-specific measure of inflammation). Other markers of the status of vitamin D were seasons and skin pigmentation, but not adiposity and hepatic inflammation.

The team suggests that according to their findings IBD darkly pigmented patients should be carefully monitored, particularly during the winter. However, the team highlights that larger randomized studies are needed to confirm their findings and actually establish the role of intestinal inflammation (and the use of ESR) as a marker for vitamin D status in IBD.