Examining Vitamin D's Role in Type 1 Diabetes
Studies suggest that vitamin D may play a role in preventing and treating diabetes. Type 1 diabetes is an autoimmune disease that results from destruction of the insulin-producing beta cells of the pancreas. Insulin is the key hormone that controls the blood glucose (sugar) levels. Without insulin, glucose doesn’t enter the cells that make up your muscles and blood glucose levels rise, especially after you eat a meal.
Type 1 diabetes used to occur only in children and was called juvenile diabetes or insulin-dependent diabetes. During the past 20 years, adults also have been diagnosed with type 1 diabetes, so it now has a more generic name.
Describing type 1 diabetes
Type 1 diabetes usually begins abruptly, although the disease may have been simmering for years. Researchers have seen autoantibodies against pancreatic beta cells in the blood long before the onset of clinical disease. Some of the major features of type 1 diabetes include the following:
Usual onset in children
Underweight condition of the patient
Presence of glutamic acid decarboxylase (GAD) autoantibodies in the blood, consistent with the autoimmune condition
Sudden onset of increased thirst, increased urination, increased hunger, and weight loss
Episodes of ketoacidosis, a condition where the blood glucose levels are very high and the body tears down protein and fat to make glucose, which makes the blood become very acidic; this is a life-threatening condition
Absolute need for insulin to sustain life
Need to balance insulin, food, and exercise to avoid both high and low blood glucose
Development of the following complications if blood glucose isn’t kept at a reasonable level over ten or more years:
Nerve disease, including pain and loss of sensation
Heart attacks and strokes
Type 1 diabetes: treatment and prognosis
Treatment of type 1 diabetes requires insulin, which is usually administered through a pen injection device, or an insulin pump, or the old mainstay of a needle-and-syringe. The insulin treatment must be balanced by the amount and type of food eaten and exercise. Insulin and exercise lower the blood glucose; food raises it.
A person with type 1 diabetes has to measure his blood glucose at least four times daily, usually before meals, and then he decides on an insulin dose based on the current blood glucose and the grams of carbohydrate to be eaten. Measurements after meals are also needed to fine-tune the control of blood glucose.
One of the treatment goals is to keep the level of hemoglobin A1c as close to normal as can be safely accomplished. The American Diabetes Association and Canadian Diabetes Association have set a goal of less than 7 percent for hemoglobin A1c. This is the level at which long-term complications are almost the same as in non-diabetics (except for heart attacks and strokes).
The prognosis for type 1 diabetes is much better today than it was 60 years ago. Today a patient has the ability to measure his or her blood glucose easily and can then respond with the appropriate amount of insulin, calories, or exercise. Insulin pumps are available that can slowly provide insulin under the skin at a rate similar to what a normal pancreas would supply.
Vitamin D's role in type 1 diabetes
Geographic location seems to play a part in the development of type I diabetes with risk increasing as you move away from the equator. Your location on Earth contributes to the amount of vitamin D your body produces, so this type of observation is suggestive, but not proof, that vitamin D affects the development of type 1 diabetes.
When you look into the science, there are a number of interesting studies that support this idea:
Finland, a country that is at latitude far from the tropics, has the highest incidence of type 1 diabetes in the world. In the late 1960s, it was common to supplement an infant’s diet with 2,000 IU vitamin D. When researchers compared the development of type 1 diabetes in people 30 years later based on whether their mothers recalled giving them vitamin D during the first year after birth, they found an 80 percent reduction in the risk of type 1 diabetes later in life.
Use of cod liver oil, a good source of vitamin A, vitamin D, and omega 3 fatty acids in the first year of life was associated with a lower risk of developing type 1 diabetes. Unfortunately, in the same study, supplemental vitamin D failed to affect the risk.
Calcitriol makes insulin-secreting beta cells resistant to immune system attack. The active vitamin appears to reduce the production of cytokines, substances that kill beta cells.
In people who have recently been diagnosed with type 1 diabetes, treatment with calcitriol didn’t improve their disease symptoms. This suggests that vitamin D might stop the development of the disease but isn’t necessarily good for treatment of the disease.
When given a drug similar to calcitriol, patients with a form of autoimmune diabetes called latent autoimmune diabetes experienced preservation of their beta cells, compared with patients not given vitamin D.
Not every study confirms the relationship of low vitamin D status and more type 1 diabetes. Also, the studies with calcitriol don’t necessarily mean that more supplementary vitamin D will be protective. Researchers still need to find the amount of vitamin D or serum 25-hydroxyvitamin D that protects against type 1 diabetes.