Insulin Sensitivity, Beta Cell Function, and the Role of Vitamin D Levels

What is the role of vitamin D in diabetes, and can Vitamin D be the key to unlocking a healthier life?

With Vitamin D deficiencies continuing to trend upwards, the importance of Vitamin D in Type 2 Diabetes Mellitus may be more crucial than previously believed. Claudia Gagnon, MD, of Centre Hospitalier Universitaire and her colleagues set out to examine the relationship of homeostatic levels of glucose and the supplementation of Vitamin D in patients. Vitamin D can be found in two different forms and from two different sources. Vitamin D can be found as the analogs Ergocalciferol and Cholecalciferol, or D2 and D3, respectively. Vitamin D2 can be found in food sources like mushrooms, soy milk, almond milk, liver, eggs, and cheese, while the main source of Vitamin D3 is the sun. With the prevalence of Vitamin D deficiency coming into the limelight, many kinds of cereal and other food sources have begun to fortify their foods with Vitamin D. Although Vitamin D plays an important role in the health of our bones, researchers are quickly finding out that Vitamin D deficiency is linked to hypertension, autoimmune disease, and diabetes.

Using a double-blinded, randomized, placebo-controlled study, Gagnon and her colleagues enrolled 96 participants and separated them into two groups. The first group was given 5,000 IU of Vitamin D3, while the second group was given a placebo. All participants were at least 25 years or older and were either classified as high-risk patients or patients newly diagnosed with type 2 diabetes. Patients were placed in the high-risk category based on waist circumference data or the presence of insulin resistance indicators. All participants in this trial had a baseline serum level of 55mmol/L or less. In a normal clinical setting, a level of serum Vitamin D of less than 30 mmol/L is usually considered inadequate in a healthy individual and requires correcting. Using the 2-hour Hyperinsulinemic-Euglycemic clamp data measured at baseline, Magnon and her colleagues assessed the peripheral insulin sensitivity of patients via the M-value. These assessments began in January 2013 and ended in October 2016. In addition, hepatic insulin sensitivity, beta-cell function, glucose tolerance tests, and whole-body insulin sensitivity assessments were performed and recorded.

The results of the data showed a baseline average M-value of 3.97 mg/kg/min in the treatment group, while the baseline placebo group average measured at 4.15 mg/kg/min. After the 6-month mark, however, the treatment group measured at 4.88 mg/kg/min, while the placebo group measured at 4.12 mg/kg/min (P=.009). In the measure of patients with prediabetes, an M value increase of 1.25 mg/kg/min was observed in comparison to the placebo group that experienced a decrease of insulin sensitivity by 0.56 mg/kg/min (P=0.15). Patients in the treatment group with type 2 diabetes experienced a 1.46 mg/kg/min increase in M value, while the placebo group increased by 0.08 mg/kg/min (P=0.3). These P values suggest significance in the data presented and may help clinicians in the fight against insulin resistance.

The above data showed a significant improvement in the sensitization of insulin in the peripheral system of the body. There were significant increases in the M-values of those who were supplemented with 5,000 IU’s of Vitamin D versus the M-value of the placebo group. Although a significant effect was not observed in the comparison of non-diabetic patient M-values, a benefit was found in the disposition index of the treatment group when compared to that of placebo (P=.039). The disposition index is a way to measure the beta-cell function of the body. This is significant because, over time, the beta cells of a patient with diabetes begin to deteriorate, hindering the mechanism of insulin secretion and absorption. Larger studies of the potential benefits that Vitamin D may have on diabetes and overall health should be undertaken.

Practice Pearls

• The role of Vitamin D and overall health may be more significant than previously thought
• According to the results of the data set, Vitamin D increases peripheral insulin sensitivity in patients that were supplemented with it
• In the future, it is important to increase the number of participants of the study to increase the legitimacy of the results.

 International Journal of Endocrinology; Volume 2010, Article ID 351385, 18 pages

https://dx.doi.org/10.1155/2010/351385

Published online 2019 Apr 6. doi: 10.3390/nu11040794

Usif Darwish, PharmD Candidate, Florida A&M University, College of Pharmacy & Pharmaceutical Sciences