Vitamin D and Bone Health in Children with Celiac Disease in High Sunlight Regions (+Video)

Celiac.com 08/18/2025 - Celiac disease is a condition that affects how the body reacts to gluten, a protein found in wheat, barley, and rye. It can interfere with the absorption of essential nutrients, especially in children. One of the nutrients often impacted is vitamin D, which plays a key role in bone development, immune function, and calcium balance. Although vitamin D can be obtained through sunlight, not everyone living in sunny areas has healthy levels. This study looked at children with newly diagnosed celiac disease in Uzbekistan, a country with over 300 days of sunshine per year, to see whether they still suffered from vitamin D deficiency—and how this deficiency affected their health.

Purpose of the Study

The researchers set out to explore two main questions: First, what are the levels of vitamin D in children with newly diagnosed celiac disease who live in a sunny climate? Second, how do vitamin D levels relate to other health markers, such as growth, bone health, and blood chemistry?

Who Was Studied

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The study involved 60 children between the ages of 1 and 16 years who had recently been diagnosed with celiac disease. These diagnoses were made using established international guidelines. The average age of the children was around 6 years old. Their results were compared to those of 31 healthy children of similar age who did not have celiac disease. Blood tests were taken from all participants to measure levels of vitamin D, calcium, phosphorus, a bone enzyme called alkaline phosphatase, and a hormone called parathormone that regulates calcium in the body.

Key Findings

Low Vitamin D Levels Despite High Sun Exposure

One of the most surprising results was that even in a country with intense year-round sunlight, children with celiac disease had significantly lower levels of vitamin D than healthy children. On average, their vitamin D levels were less than one-third of the levels found in the control group.

Specifically, 80 percent of children with celiac disease had a clear vitamin D deficiency, meaning their blood levels were below 20 nanograms per milliliter. A concerning 25 percent of them had very severe deficiency, with levels under 10 nanograms per milliliter. The remaining 20 percent had vitamin D levels that were considered low but not yet deficient.

Growth and Bone Development Were Affected

Children with lower vitamin D levels often showed signs of stunted growth and poor weight gain. Over 40 percent of the children had noticeable short stature or growth delays. Additionally, visible bone deformations, such as bowed legs or a curved spine, were more common among those with the most severe vitamin D deficiencies. The lower the vitamin D levels, the more likely the child was to show signs of bone or skeletal problems.

Biological Markers of Bone Stress Were Elevated

Children with lower vitamin D levels also showed higher levels of alkaline phosphatase and parathormone. These substances in the blood usually increase when the bones are under stress or when the body is trying to compensate for low calcium levels. The study found an inverse relationship—meaning that as vitamin D went down, these stress markers went up. This suggests that the children's bones were being negatively affected by both the disease and the lack of vitamin D.

Why This Happens Even in Sunny Climates

The results suggest that just living in a sunny area is not enough to guarantee healthy vitamin D levels—especially for children with celiac disease. There are several reasons for this. First, intestinal damage caused by celiac disease can prevent the body from properly absorbing vitamin D from food. Second, children may not be spending enough time outdoors or may wear clothing that covers most of their skin. Third, even when skin is exposed, if the digestive system is inflamed or damaged, it may still struggle to process the vitamin D effectively.

Implications for Children with Celiac Disease

This study sends a clear message: children with celiac disease are at high risk for vitamin D deficiency, even in sunny environments. Low vitamin D levels can lead to serious problems, especially during the years when children are growing rapidly. Stunted growth, poor weight gain, and deformities in bone structure were all associated with low vitamin D in this group.

Because the children in this study were newly diagnosed, their symptoms reflect the kinds of issues that may appear before treatment begins. This means that early diagnosis and attention to vitamin D status can play a major role in preventing long-term health complications. Blood tests that check for vitamin D, calcium, and related markers should be a standard part of managing celiac disease in children.

Conclusion

The findings of this study highlight the importance of monitoring vitamin D levels in children with celiac disease, even in regions with plenty of sunshine. It challenges the assumption that natural sunlight is always enough to prevent deficiency. For parents, doctors, and caregivers, this study reinforces the need for early screening and nutritional support. Supplementing with vitamin D and calcium, correcting intestinal inflammation through a gluten-free diet, and tracking growth closely could all help children with celiac disease achieve better long-term health outcomes.

Read more at: frontiersin.org

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