Vitamin D Deficiency and Its Relationship to Diabetes
By Sharon Howard

Researchers have found that Vitamin D, in addition to keeping our bones strong (along with calcium), plays important roles in other body systems. Vitamin D deficiency is recognized as a pandemic (1) and is associated with increased risk of common cancers, autoimmune diseases, hypertension and infectious diseases. Vitamin D deficiency predisposes people to type 1 and type 2 diabetes (2). In type I, a deficiency early in life is linked with later onset of type 1 diabetes. With type 2 diabetes, Vitamin D deficiency impairs insulin synthesis by impairing beta- cells. We cannot say that Vitamin D deficiency cause diabetes, nor does it cure diabetes.

So why all the interest?
In addition to the insulin connection, Vitamin D, along with calcium, reduces the production of inflammatory chemicals called cytokines. Inflammation is an underlying factor in heart disease, cancer and diabetes. Vit D deficiency is a widespread problem, and could be protective in these major disease concerns.

Vitamin D: How we get it
Vitamin D is found in only a few foods - fatty fish like salmon, trout, sardines, mackerel, cod-liver oil, tuna, egg yolk, Swiss cheese, shrimp, and milk fortified with Vitamin D. In the United States, milk, and some selected products such as juice, yogurts, bread and cheeses are fortified with Vitamin D. It is also found in multivitamins in the current recommended dose of 400 IU. Supplements are now available in larger amounts as high as 50,000 IU Vitamin D3.

Our major source of Vitamin D is exposure to sunlight. In Northern climates, individuals may not get enough sunlight to supply adequate Vitamin D, so supplements are important. Sunscreens can also limit the amount of Vitamin D absorbed.

Certain medications may increase your need for Vitamin D. Corticosteroids such as prednisone, Orlistate (Alli and Xenical), Cholestyramine (Questran, LoCholest, Prevalite), and seizure medications such as phenobarbitol and dialantin.

What are the consequences of Vitamin D deficiency?
Dr. Robert Heaney of the Creighton University Osteoporosis Research Center, in a presentation April 9, 2010, listed these concerns (3):

- Bone diseases, falls, & fractures
- Hypertension
- Increased risk of cardiac disease and death
- Increased risk of multiple sclerosis, type 1 diabetes
- Prematurity, low birth weight, increased Caesareans
- Diabetes & metabolic syndrome
- Periodontal disease, bacterial infections, tuberculosis and pneumonia
- Decreased resistance to infection
- Various cancers—particularly breast, colon and prostate cancer

What can you do?
First, have your Vitamin D level tested with a blood test:

- Adequate levels—30-100ng/ml
- Insufficient levels-21-30 ng/ml
- Deficiency 0-20 ng/ml
- Toxicity – greater than 100 ng/ml

The treatment may depend on the level of deficiency. Vitamin D3 is the active form and most widely recommended. Some people may take 2,000 IU daily or 20,000-50,000 IU weekly for 2 to 8 weeks and then retest. Toxicity levels are difficult to achieve, but upper limits are noted at 30,000 IU weekly for correcting severe deficiency. The body needs 32ng/ml for the full biological benefit of Vitamin D, but the recommended range is 50-60 ng/ml for cardiovascular and cancer prevention.

Watch for more research!
The recommended daily dietary levels are being re-evaluated, and so stay tuned for more information. In the meantime, you can optimize your Vitamin D levels with Vitamin D rich foods, some sunlight exposure, and the use of dietary supplements.

Article References:
1. Holick, MF, Chen,T. (2008) Vitamin D deficiency: a worldwide problem with health consequences Am J Clin Nutr 2008;87(suppl):1080S-6S.
2. Mathieu, C. et al. (2005) Vitamin D and Diabetes Diabetologia (2005) 48:1247-1257.
3. Heaney, R. (2010) Vitamin D - Mechanism of Action - Status of Evidence. Online presentation April 9, 2010,`s Sharon Howard is a registered dietitian with more than 25 years experience counseling individuals with nutrition issues including diabetes, weight loss, eating disorders, lipid disorders, celiac disease, renal disease, and bariatric nutrition. She is also a charter Fellow of the American Dietetic Association and a Certified Diabetes Educator.

Originally posted by on October 15, 2010.