Vitamin D and Insulin Sensitivity

Insulin Crystals - Photo by Jeruma Oliveira

Vitamin D deficiency has gotten some attention in various studies because it may have an affect on insulin sensitivity. When vitamin D deficiency occurs, rates of abnormal blood sugar metabolism and insulin resistance tend to increase, which is associated with obesity, metabolic syndrome, diabetes, and a host of other health conditions. Several studies have shown favorable results with vitamin D supplementation.

Here are results of some studies that looked at vitamin D and insulin sensitivity:

• One study found that obese adolescents who had a deficiency in vitamin D who received vitamin D supplementation experienced improved insulin sensitivity when compared with a placebo group.
• One study looked at pregnant women and found that those who took vitamin D experienced lower fasting blood sugar levels when compared with the placebo group.
• Another study found that middle-aged adults with pre-diabetes had significant increased insulin sensitivity after receiving vitamin D and calcium supplementation.
• Vitamin D supplementation seemed to be associated with lower blood sugar levels and significantly improved insulin sensitivity in patients with type 2 diabetes mellitus in another study.

Each of these studies looked at different populations, and each recommends further testing of larger numbers of people and for longer periods of time. Although scientific studies try to level the playing field and take out as many variables as possible, some differences may still exist in those who receive treatment and those who receive a placebo. Randomly taking multiple vitamins may not be particularly helpful and could even harm one's health, so it is always important to clearly communicate with a healthcare provider what, if any, vitamins and supplements one is taking.

So, how does vitamin D produce these effects? Not all studies consistently show the same results; however, I thought these research studies might provide added information that readers might find helpful for those whose health care provider has recommended vitamin D supplementation. Taking a supplement to return numbers to a normal range might not be a highly motivating factor, but if a supplement could help to prevent diabetes or improve diabetes treatment, this might play a significant role in tipping the balance toward choosing to consistently take the supplement.

Vitamin D has properties that produce anti-inflammatory responses in the body; low levels of vitamin D are associated with inflammation in the body. Many body systems may be affected by chronic inflammation which may occur with vitamin D deficiencies. Vitamin D may help to regulate the insulin receptor gene and may play a role in moving blood sugar from the blood into muscles where the body can use it.

Many people in the United States have lower than recommended levels of vitamin D. It is found in some foods, such as egg yolks, fatty fish, mushrooms, and liver and is commonly added to milk and some other foods and beverages. The sun's ultraviolet rays can help a person's body form vitamin D. Levels may be lower due to dietary choices, a person's race or ethnicity, age, less sun exposure, and more people using sunscreen to protect the body from the potential for skin cancer.

Thanks so much for visiting my Fit Tips 4 Life blog. This article is for informational purposes only and should not be considered medical advice. If you have any questions or concerns related to your health, contact your healthcare provider to determine the safest, most effective approach for you.

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References

Asemi, Zatolla, et. al. Vitamin D Supplementation Affects Serum High-Sensitivity C-Reactive Protein, Insulin Resistance, and Biomarkers of Oxidative Stress in Pregnant Women, The Journal of Nutrition, 143.9 (September 2013): 1432-8.

Gagnon, Claudia, et. al., Effects of Combined Calcium and Vitamin D Supplementation on Insulin Secretion, Insulin Sensitivity and [beta]-Cell Function in Multi-Ethnic Vitamin D-Deficient Adults at Risk for Type 2 Diabetes: A Pilot Randomized, Placebo-Controlled Trial: e109607, PLoS One 9.10 (October 2014).

Joffe, Alain, Correcting Low Vitamin D Levels in Obese Adolescents Improves Insulin Sensitivity, Journal Watch, Pediatrics & Adolescent Medicine (March 20, 2013).

National Center for Environmental Health, CDC's Second Nutrition Report: Vitamin D deficiency closely related to race/ethnicity online article accessed on 6/4/2015.

Talei, Afsaneh, et. al., The effect of vitamin D on insulin resistance in patients with type 2 diabetes Diabetology & Metabolic Syndrome 5 (2013).