Endocrine Abstracts

Background: Type two Diabetes Mellitus (T2DM) is a rapidly growing crisis. Data from several T2DM cohorts demonstrate that elevated levels of serum branched chain amino acids (BCAAs) increase the risk of the disease. BCAAs levels correlate with parameters that reflect glycemic control. Elevated levels of BCAAs in T2DM is associated with a higher risk of complications. Vitamin D plays an important role in regulating insulin action on target tissues. Normalization of serum vitamin D levels in T2DM patients with vitamin D deficiency was shown to improve their glycemic control.

Aim: To determine whether the positive effect of vitamin D on insulin sensitivity in T2DM could be partially mediated through the ability of vitamin D to reduce BCAAs.

Methods: A case-control design was used followed by a therapeutic intervention cohort for 3 months. In the case control part, 231 subjects were recruited, 137 subjects had a confirmed diagnosis with T2DM and 93 subjects were disease free. Patients were frequency matched with the controls by age and body mass index. The serum levels of 25(OH) vitamin D, glucose, total cholesterol, triglycerides, and BCAAs were measured from the serum samples of all subjects while HbA1c levels were measured from whole blood samples. Of the 137 subjects with T2DM, 26 subjects had 25(OH) vitamin D deficiency. These patients were recruited to a therapeutic intervention where they received 50,000 IU of vitamin D₃ tablets weekly for 3 months while maintaining standard treatment of care. Following the intervention; 25(OH) vitamin D, glucose, HbA1c, total cholesterol, triglycerides and BCAAs were measured.

Results: T2DM subjects had significantly higher levels of glucose, HbA1c, triglycerides and BCAAs (P<0.05) but significantly lower levels of 25(OH) vitamin D. Serum levels of BCAAs negatively correlated with serum 25(OH) vitamin D (P=0.043, r=-0.173). In the intervention cohort, vitamin D supplementation significantly lowered the serum levels of glucose, triglycerides, BCAAs (P<0.05) and the whole blood levels of HbA1c (P<0.05) compared to baseline levels measured a day prior to the intervention.

Conclusion: Normalization of 25(OH) vitamin D using clinically approved supplementation protocols significantly reduces circulating levels of BCAAs in T2DM patients; an effect that may reduce T2DM patient risk of future complications.