This study indicated that people who are low in vitamin D when they are first diagnosed with type 1 diabetes (T1D) may face a more aggressive disease onset and a more challenging start.
Published in the Journal of the Endocrine Society, the study looked at 18 children, teens, and adults within six months of being diagnosed with T1D. Researchers measured their vitamin D levels and compared them to how much insulin their bodies could still make, a sign of how many insulin-producing beta cells were still working.
The findings revealed that 56% had vitamin D deficiency, meaning their levels were below 30 ng/mL. Those with low vitamin D had about half as much beta cell function as people with healthy levels. In other words, their bodies were making much less of their own insulin after diagnosis of Type 1 Diabetes.
“These results suggest that having enough vitamin D could mitigate the autoimmune aggression against the insulin-producing cells at the onset of Type 1 Diabetes,” said Dr. Camillo Ricordi, Director Emeritus of the DRI. “Checking and correcting vitamin D levels in people at risk for type 1 diabetes may be an important step in preventing Type 1 Diabetes and other autoimmune diseases. In fact, it has been shown that Vitamin D supplementation can reduce the incidence of all autoimmune diseases by almost 40%.”
Vitamin D is already known to modulate the immune system, and its critical role has been demonstrated beyond autoimmune disease, including in the prevention of critically severe viral diseases like COVID-19. In fact, in the setting of COVID-19, low Vitamin D levels before viral infection was associated with a 14-time fold increase in the risk of developing severe COVID-19 and even death. This could indicate that the tolerance promoting effect of Vitamin D could be associated with benefits preventing both severe forms of autoimmunity and viral disease conditions that are both associated with hyper-immune and hyper-inflammatory reactions.
The DRI team says more research is needed to find out if correcting vitamin D deficiency could help prevent Type 1 Diabetes and also help people diagnosed with T1D to maintain insulin production longer.
Reference:
Baidal DA, Alvarez AM, Padilla N, et al. 25(OH) Vitamin D Levels and Severity of Type 1 Diabetes in Youth and Adults With Recent-Onset Disease. J Endocr Soc. 2025;9(6):bvaf061. doi:10.1210/jendso/bvaf061
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