Serum levels of vitamin D make a difference for people with ulcerative colitis. That is the conclusion of a new study from Beth Israel Deaconess Medical Center. Ulcerative colitis is a condition in which the immune system attacks the lining of the colon, causing inflammation and distress. (You can listen to an interview about the disease here.)
Vitamin D and Ulcerative Colitis:
Previous research suggested that people with inflammatory bowel disease are often deficient in vitamin D. In the current study, researchers collected blood samples from 70 patients in remission from ulcerative colitis. These samples were analyzed for levels of 25-hydroxyvitamin D. Vitamin D circulates within the body as 25-hydroxyvitamin D. However, the doctors caring for the patients were not told the results. Such a procedure allowed for “blinding,” critical in medical research.
A year later, doctors compared patients who had suffered relapses of the disease to those who were still well. People with lower vitamin D levels were more likely to experience a relapse than those with higher levels of this nutrient.
The Magic Number for 25-Hydroxyvitamin D:
The researchers identified a threshold of 25-hydroxyvitamin D- 35 ng/mL- that separated the two groups. They hypothesize that vitamin D may help protect the cells lining the colon and promote a beneficial balance of intestinal microbes.
Will Supplementation Help?
Unfortunately, this research can’t answer a question patients ask: do vitamin D supplements change the outcome? We don’t know. Taking a supplement might be worth a try. Anyone who does so should consider taking a moderate dose of vitamin D3 every day rather than an enormous dose once a month or less often. A recent meta-analysis looking at vitamin D supplements for reducing respiratory infections found that daily dosing was more helpful than bolus dosing (Martineau et al, BMJ, Feb. 15, 2017).