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Inflammatory bowel diseases are linked to vitamin D deficiency

Inflammatory bowel diseases are linked to vitamin D deficiencyInflammatory bowel diseases such as Crohn’s disease and ulcerative colitis are becoming more and more common, even among young people. Diet, gut flora, and immune defense play a major role. Also, patients with inflammatory bowel disease seem to have lower blood levels of vitamin D, which is linked to the chronic inflammatory state and the progression of the disease. This was demonstrated in a study that was published recently in the science journal Medicine.

Chronic inflammatory bowel diseases (also known as IBD) are most prevalent in western countries and at northern latitudes, and the rate of this type of ailment is growing. In severe cases, the conditions may require bowel surgery and colostomy, so there is an urgent need to focus on prevention and effective therapies.
In the new study, the scientists measured serum levels of vitamin D in 104 patients suffering from inflammatory bowel disorders (Crohn’s disease and ulcerative colitis), and in 14 healthy controls. The patients’ diagnoses were based on clinical studies that related to European guidelines (ECCO-ESGAR). The activity of the inflammatory bowel diseases was rated according to special clinical test methods. Many of the patients also suffered from comorbidities such as cardiovascular disease, diabetes, metabolic syndrome, rheumatoid arthritis, and other autoimmune disorders where chronic inflammation is part of the picture.
According to the study, 66.3 percent of the patients suffering from bowel inflammation had insufficient levels of vitamin D in their blood (below 50 nmol/L), while 32.6 percent were vitamin D-deficient (their levels were under 30 nmol/L). The control group had higher vitamin D levels on average. The scientists also observed that serum levels of vitamin D were statistically related to levels of CRP (c-reactive protein) and other inflammation markers. Therefore, they concluded that patients with inflammatory bowel diseases generally have lower levels of vitamin D in their blood. This has something to do with the chronic inflammation in the bowel and the progression of the disease.
Lack of vitamin D in patients with inflammatory bowel diseases is also linked to worse therapy response and a greater risk of surgical intervention. Based on their findings, the scientists recommend for patients to strive to have optimal blood levels of vitamin D, and that can be achieved through more sun exposure (during the summer period) and supplementation.

  • Crohn´s disease primarily affects the distant part of the small intestine and/or the colon. The chronic inflammation can cause scarring or fistulas, where the inflammation creates tunnels between the intestine and surrounding organs.
  • Ulcerative colitis starts by the rectum, and the inflammation can spread up through the large intestine (colon). The most common symptoms are painful bowel movements, and blood in the stool. Anemia may also occur.

Vitamin D’s role in the gut flora and the immune defense

Inflammatory bowel diseases are primarily linked to a disrupted immune defense, gut flora imbalances (dysbiosis), structural changes in the intestinal mucosa, and hereditary factors.
A major part of our immune defense is located in the intestine, where it handles microbes and toxins from food and potentially harmful microbes from the intestinal flora to prevent them from spreading in an unwanted manner.
It is commonly known that vitamin D is important for our innate immune defense that fights most harmful microbes without causing any symptoms. Vitamin D is also important for the adaptive immune defense that is more specialized and can form antibodies. In addition, vitamin D is needed to regulate inflammatory processes that must be terminated once an infection has been defeated. Other studies suggest that vitamin D is important for the actual gut flora and the benign bacteria that produce B vitamins.

Why do patients with inflammatory bowel diseases often lack vitamin D?

Inflammatory bowel diseases are more common at northern latitudes because people living there are only able to produce vitamin D in their skin during the summer period, where the sun sits high in the sky. Our ability to synthesize vitamin D is challenged even more by things like spending too much time indoors, overuse of suncream, veiling, ageing, and being dark-skinned. We get a small amount of vitamin D from our diet (oily fish, eggs, and high-fat dairy products), but patients with inflammatory bowel diseases may suffer from malabsorption issues. Therapies that involve the use of immune-suppressing drugs (corticosteroids) and cholesterol-lowering statins may also interfere with the body’s ability to utilize vitamin D.
In addition, we need magnesium from coarse greens to help us convert the type of vitamin D that we synthesize in the skin or get from supplements into the form of the vitamin that is measured in the blood. It is advisable to have optimal blood levels of vitamin D, which should ideally be above 75 nmol/L and preferably around 100-120 nmol/L.


Antonia Topalova-Dimitrova et al. Lower vitamin D levels are associated with the pathogenesis of inflammatory bowel diseases. Medicine. 2023

Gominak SC. Vitamin D deficiency changes the intestinal microbiome reducing B Vitamin production in the gut. The resulting lack of pantothenic acid adversely affects the immune system, producing a “pro-inflammatory” state associated with atherosclerosis and autoimmunity. Med Hypotheses 2016

Anne Marie Uwitonze, Mohammed S Razzaque. Role of Magnesium in Vitamin D Activation and Function. Journal of the American Osteopathic Association. 2018

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