In a recently published article, there was found a strong association between low levels of Vitamin D3 and the development of insulin resistance.   

Vitamin D3 deficiency appears to be a widespread phenomenon worldwide. In the past, people used to exercise or work outdoors, but now people choose to spend more time indoors. When we are outdoors, we tend to be covered by clothing or sunscreen. This may result in reduced exposure to sunlight and therefore a corresponding reduction in UV exposure. 

Another contributor for Vitamin D3 deficiency is obesity.  As our society has gradually become heavier, free fatty acids in the bloodstream are increased which inhibits the absorption and activity of Vitamin D3. Numerous studies have shown that Vitamin D3 deficiency leads to considerable metabolic changes. Total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) change for the worse.  

As Vitamin D3 decreases, it lowers the activity of pancreatic beta cells which secrete insulin when glucose levels rise. The insulin-responsive cells which use the insulin secreted by pancreatic beta cells are less active or ‘resistant’ in Vitamin D3 deficiency. Insulin resistance can lead to overweight, obesity, elevated cholesterols and triglyceride, heart disease and vessel disease. The leading cause of diabetes is insulin resistance.  

Vitamin D3 is an essential fat-soluble vitamin that plays an important role in maintaining bone function, regulating the immune system, and reducing the risk of metabolic disorder such as diabetes. There are three main sources of Vitamin D3:  

  • Sunlight or ultraviolet (UVB) radiation provides 7-dehydrocholesterol which is absorbed into the skin.  Approximately 70% of Vitamin D3 is made this way. 
  • Vitamin D3 can also be supplemented through food.  Common sources of dietary intake containing Vitamin D3 are oily fish, milk, juice, grains, etc. Only about 30% of Vitamin D3 is derived in this way. One would need to drink about 8 gallons of milk PER DAY to get enough Vitamin D3 which is not recommended!  
  • Oral supplements are another way of supplying the body with needed Vitamin D3. As with all supplements, I recommend high quality, American made and third party tested.  

Timely intervention can lead to remission or even disappearance of insulin resistance. Make sure your Vitamin D3 level is normal. The 25-hydroxy Vitamin D blood test is the most accurate way to measure how much Vitamin D is in your body. Acceptable ranges differ by various healthcare organizations.  In my practice, we follow the American Association of Clinical Endocrinologist guidelines which states a normal blood Vitamin D3 levels needs to be between 40 and 100.   

The U.S. Recommended Daily Allowance (RDA) for Vitamin D3 is 400-800 IU daily for the average adult. Keep in mind, RDA is the minimal recommendation to ‘prevent’ disease. If you are deficient of Vitamin D3, you will need a much higher dose to build-up fat stores, and which could be as much as 10,000 IU daily or more for a period of time. Once deficient of Vitamin D3, you will need to continue supplements for a lifetime or move to Florida to get more daily sunshine!  

Ask your health care provider to check your Vitamin D3 and maintain a level in the mid to high range. Not only does this lower your risks of insulin resistance but can improve fatigue and muscle aches. We all could use a little more energy! 

Being healthy is a never-ending task but should NEVER be a chore.   

Live Long, Live Healthy! 

Dr. Julie Wood is a Nurse Practitioner and has been serving the Middle Tennessee area for more than 30 years, specializing in adults with obesity, prediabetes and diabetes. Office is located at 401 First Avenue, Mt. Pleasant, TN and statewide with telehealth. Dr. Wood can be reached at 931-325-5560,,  

Articles are meant to be informative and should never replace the advice of your health care provider.