Gluten-Free Diet in Co-Existent Celiac Disease and Type 1 Diabetes Mellitus: Is It Detrimental or Beneficial to Glycemic Control, Vascular Complications, and Quality of Life?

Celiac disease (CeD) is associated with type 1 diabetes mellitus (T1DM), and both have the same genetic background. Most patients with T1DM who develop CeD are either asymptomatic or have mild CeD-related gastrointestinal symptoms. Therefore, children affected by T1DM should undergo screening for asymptomatic CeD. The aim of this review is to highlight the influence of a gluten-free diet (GFD) on glycemic control, growth rate, microvascular complications, and quality of life in patients with T1DM and CeD. PubMed, Google Scholar, Web of Science, and Cochrane Central databases were searched. Reports reviewed were those published from 1969 to 2022 that focused on the interplay of T1DM and CeD and examined the effect of diet on glycemic control, growth rate, and quality of life. The most challenging aspect for a child with T1DM and CeD is that most GFD foods have a high glycemic index, while low glycemic index foods are recommended for T1DM. Interestingly, dietary therapy for CeD could improve the elevated HbA1c levels. Avoiding gluten added to a diabetic dietary regimen in T1DM patients might impose practical limitations and lead to important restrictions in the lifestyle of a young patient. Consequently, non-adherence to GFD in patients with T1DM and CeD is common. GFD in patients with T1DM and CeD seems to lower the incidence of micro- and macrovascular complications, but this requires further investigation. It seems that adherence to GFD in young patients with T1DM and CeD leads to regular growth and a stable body mass index without any negative effect on HbA1c or insulin requirements. Furthermore, the lipid profile and quality of life seem to have improved with the introduction of GFD.