Vitamin D Deficiency & High Blood Sugars

According to, normal fasting blood sugar levels are between 70 and 99 mg/dL; fasting blood sugar levels between 100 and 125 mg/dL are classified as pre-diabetes; and fasting blood sugar levels over 126 on two consecutive tests are consistent with a diagnosis of diabetes. High blood sugar levels occur when normal transport of sugar into the body's cells, which is regulated by the hormone insulin, is compromised. Vitamin D is a fat soluble vitamin primarily associated with maintenance of normal calcium metabolism.


There are three forms of diabetes mellitus, all of which affect how your body processes glucose. Type I diabetes, which used to be called "juvenile" or "insulin-dependent" diabetes, is a disease that results from the inability of the cells of the pancreas to produce sufficient insulin. Type II diabetes, which used to be called "adult-onset" or "non-insulin-dependent" diabetes, is a disease that results from either an underproduction of insulin or a reduced response to insulin. Finally, gestational diabetes is a complication of pregnancy and generally resolves when the baby is delivered.

Vitamin D

Vitamin D is produced in the skin of animals, including humans, when they are exposed to light. Vitamin D is essential in the absorption of calcium in the gut, according to the Office of Dietary Supplements, which also reports that vitamin D is now thought to play a role in the prevention of type I and type II diabetes and glucose intolerance, among other conditions.

Vitamin D and Diabetes: The Scientific Evidence

A study by Hyppönen, et al., published in the November 2001 issue of "Lancet," showed that supplementation of vitamin D in infants reduced the incidence of type I diabetes. Pittas, et al., reported results from the longitudinal Nurses Study that showed a 33 percent reduced risk of type 2 diabetes for women with a combined intake of over 1200 mg calcium and over 800 IU vitamin D compared to women with a combined intake of less than 600 mg calcium and less than 400 IU of vitamin D in the March 2006 issue of "Diabetes Care."

Vitamin D Deficiency and Glucose Intolerance

Chiu, et al., studied the effect of hypovitaminosis D, or vitamin D deficiency, on glucose tolerance and reported their findings in the May 2004 issue of the "American Journal of Clinical Nutrition." They found that subjects with a vitamin D deficiency are at higher risk of glucose intolerance and metabolic syndrome.

Other Uses of Vitamin D

Vitamin D is essential for calcium absorption and for maintaining appropriate blood calcium levels. It is also essential for bone growth and bone remodeling, which is the steady-state formation and resorption of bone material. A deficiency of vitamin D in infants is associated with rickets, and vitamin D deficiency in adults can be associated with osteoporosis.