Vitamin D Deficiency Could Increase Risk for Diabetes
By James J. Kenney, PhD, RD, FACN
Vitamin D is a fat-soluble vitamin that plays a number of important roles in the body, including maintaining the health of your bones, teeth and joints, and assisting immune system function. It’s found in foods and it’s also produced by the body in response to exposure to the sun. When the sun’s UVB rays are exposed to bare skin, the body converts a cholesterol derivative into Vitamin D. We now know that every cell and tissue within the body has a Vitamin D protein receptor. You may not be getting enough sun exposure if you are spending more time at home, and in the office or your car. Other contributors include the shorter days of winter, and increased use of sunscreen in the summer.
A Vitamin D deficiency can show up in symptoms such as bone pain and muscle weakness, depression, a weakened immune system, obesity, high blood pressure, psoriasis, osteoporosis, chronic fatigue, Alzheimer’s disease, cancer, hypertension, cardiovascular diseases, bone fractures and type 2 diabetes.
Is There Really a Link Between Vitamin D and Diabetes?
But before we start recommending that people take supplements, we need to prove there is a cause and effect association. For example, higher blood levels of vitamin E and beta-carotene levels were shown in many observational studies to be linked with a reduced risk of cardiovascular disease and cancer.
However, when the data from all the previous trials were pooled, they showed that supplements of vitamin E and/or beta-carotene are likely harmful, at least for some groups of people.
Vitamin D Plus Calcium
An earlier placebo-controlled trial designed to examine the impact of a combined 700 IU Vitamin D plus 500mg calcium supplements on bone health did note that the 40% of subjects who took the supplement whose blood sugars were modestly elevated were less likely to progress to having type 2 diabetes over the next 3 years.1
Improving Insulin Sensitivity
A small study looked at a group of 81 insulin resistant women age 23-68 in New Zealand. Subjects were randomly assigned to receive either a 4000 IU vitamin D supplement or a placebo. After 6 months those taking the vitamin D supplement had significant improvements in insulin sensitivity as well as lower fasting insulin levels.
The researchers noted that insulin resistance was most improved in those whose blood levels of vitamin D rose into the 80 to 119 nmol/L range, which is well in excess of the 30 nmol/L range believed adequate for optimal bone health. Such a high level of vitamin D cannot generally be attained by diet alone in most people and would require either fairly high dose supplements of Vitamin D3 and/or a significant amount of sun exposure.2 Improving insulin sensitivity should improve blood sugar control in people with type 2 diabetes and also help prevent the development of type 2 diabetes as well.
Other Benefits of Vitamin D
Maintaining a good level of vitamin D can help bring down the level of the parathyroid hormone (PTH) levels. Over time, this may help with weight loss, therefore lowering the risk of obesity.
Vitamin D can help regulate the body’s fat supplies. It increases the hormone called lepti, which signals to your body that you are full. A lower hunger level results in less overeating.
Increasing vitamin D can help lower the amount of cortisol in your body. Cortisol is a stress hormone involved in the regulation of blood pressure. If your body has high levels of cortisol and these levels are maintained for lengthy periods of time, the result can be an increase in abdominal fat. Belly fat has been linked to diabetes type 2 and other conditions.
Two Forms of Vitamin D
Vitamin D is made by our body when sunlight acts on cholesterol in the skin. At this point it is vitamin D3 and then it is converted by the liver and then the kidneys into active vitamin D.
There are two forms of vitamin D -- vitamin D2 and vitamin D3. Vitamin D2 is a synthetic version and has a shorter shelf life. It’s cheaper to produce than Vitamin D3. Vitamin D3 is the same as the vitamin D that is produced in your body after exposure to the sun. Both D2 and D3 have to pass through your liver and kidneys in order to be converted to the active form of vitamin D.
According to studies, vitamin D3 has been shown to be more than three times as effective as vitamin D2. You must be certain to read the labels on foods that have claims about Vitamin D and ensure it contains D3 rather than D2.
Dietary sources of Vitamin D include salmon (wild typically has more than farmed), herring, sardines, halibut, mackerel, cod liver oil, canned tuna (choose light instead of white), egg yolks, mushrooms (wild are typically better than commercially-grown), and fortified foods such as milk, orange juice and cereal. Vitamin D also helps the body absorb calcium.
Be sure to talk to your doctor and consider getting a blood test to determine your level of Vitamin D. Your doctor can advise you on how much Vitamin D to take if it turns out that your level is low.
Old Recommendations for Vitamin D Need Updating
The current average daily nutrient intake for vitamin D is 200 to 600 IUs, depending on age, with a Tolerable Upper Intake Level (UL) of 2000 IU. These recommendations were established nearly 10 years ago. They now appear to be inadequate, and too low, respectively for reducing illness or death from cardiovascular disease, likely type 2 diabetes, some cancers and other ills. Ensure you’re getting an adequate amount of vitamin D to reduce your risk for diabetes.
This information is for educational purposes only. The statements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease. Consult your physician if you have any question regarding a medical condition
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