According to a hypothesis developed by Seth Bittker of the Ronin Institute, one significant factor contributing to this rise in incidence may be the increase in vitamin D supplementation and fortification in many developed countries.

Celiac researchers have known for a while that there has been a significant increase in the incidence of celiac disease in recent decades in many developed countries. Since some studies that show this are based on testing blood samples of similar populations over time, this increase in incidence is not merely due to increased awareness and testing. A key question that researches have been struggling with is: why has this increase in incidence occurred? Some researchers have suggested that there must be a missing environmental factor.

The hypothesis developed by Seth Bittker suggests that supplementation and fortification with oral vitamin D may be such a missing environmental factor. First, the active vitamin D metabolite (1,25-dihydroxyvitamin D) is often elevated in celiac disease, especially in the newly diagnosed. Second, nine distinct conditions that cause elevations in the levels of the active vitamin D metabolite in blood, are associated with increased risk of celiac disease or have indications of such an association in the literature. This suggests that elevation in the vitamin D metabolite in blood may increase the risk of developing celiac disease.

Yet other studies show that oral vitamin D exposure increases blood levels of the active vitamin D metabolite, which makes one wonder whether significant oral vitamin D supplementation and fortification may be a risk factor for celiac disease as well. One study in the literature has found that vitamin D supplementation in infancy is associated with celiac disease. Other studies show that high dose vitamin D supplementation affects the immune system, and the effects on the immune system associated with it is similarly in many ways to the immunological profile of celiac disease.

In addition, a number of epidemiological quirks of celiac disease may be explained by this vitamin D hypothesis. For example, researchers have known for decades that a large increase in incidence of celiac disease occurred in Sweden in 1984. Mandatory vitamin D supplementation of milk in Sweden began in March of 1983. Similarly, researchers are aware that there is significant variation in incidence of celiac disease in certain superficially similar countries. For example, Germany has a low incidence of celiac disease and Sweden and Finland have very high incidences of celiac disease and Vitamin D intake is much higher in Sweden and Finland than in Germany due to differences in fortification and supplementation policies.

While this is a hypothesis and additional research needs to be conducted to test it, if additional research bears it out, it has significant public health implications.

Reference:

Bittker SS. Elevated Levels of 1,25-Dihydroxyvitamin D in Plasma as a Missing Risk Factor for Celiac Disease. Clinical and Experimental Gastroenterology. 2020;13:1-15. https://doi.org/10.2147/CEG.S222353

More information on Seth Bittker is available here: http://ronininstitute.org/research-scholars/seth-bittker/

Seth Bittker
17 Edmond Street
Darien, Connecticut 06820

seth.bittker@ronininstitute.org

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