Vitamin D Important for Normal Blood Sugar Metabolism

Vitamin D supports balanced blood sugar levels and insulin sensitivity, according to a recently published study. Vitamin D is a fat-soluble vitamin ingested in the diet or made by the body upon exposure of the skin to sunlight. Many Americans have suboptimal vitamin D levels.

Researchers evaluated 5,200 adults who had completed an oral glucose tolerance test at the beginning of the study and again approximately 5 years later. Levels of serum 25-hydroxyvitamin D, which is the most accurate measurement of vitamin D in the body, were determined at the beginning of the study. Additionally, the subjects were evaluated for calcium intake using a food frequency questionnaire.

The results of the study showed that 199 of the subjects had imbalanced blood sugar metabolism. Compared to the subjects with normal blood sugar metabolism, the subjects with imbalanced blood sugar metabolism had lower serum vitamin D concentrations and calcium intake. More specifically, for each 25 nmol/L increase in serum 25-hydroxyvitamin D, there was a 24 percent decrease in the likelihood of having imbalanced blood sugar metabolism. After adjusting for confounding factors such as age, waist circumference, ethnicity, season, latitude, smoking, physical activity, family history of blood sugar issues, dietary magnesium, elevated blood pressure, serum triglycerides and fasting plasma glucose, calcium intake did not independently affect blood sugar levels. At the 5-year follow-up, only serum 25-hydroxyvitamin D was found to correlate with insulin sensitivity.

The researchers concluded that higher levels of serum vitamin D were associated with balanced blood sugar levels and insulin sensitivity.

Reference:

Gagnon C, Lu ZX, Magliano DJ, Dunstan DW, Shaw JE, Zimmet PZ, Sikaris K, Grantham N, Ebeling PR, Daly RM. Serum 25-Hydroxyvitamin D, Calcium Intake, and Risk of Type 2 Diabetes After 5 Years: Results from a national, population-based prospective study (The Australian Diabetes, Obesity and Lifestyle Study). Diabetes Care. 2011 Mar 23. Published Online Ahead of Print.