Diabetes Linked to Vitamin D Deficiency

The sun and the vitamin D that we derive from it is critical to our health. Now we learn that a lack of vitamin D from the sun is linked to diabetes.

Type 2 diabetes and vitamin D

Researchers from Harvard University and Seoul, Korea have determined that vitamin D deficiency is linked with a significantly greater risk of type 2 diabetes and insulin resistance.

The researchers, from Seoul National University College of Medicine and the Harvard Medical School, teamed up to follow 1,080 Korean middle-aged adults for five years. At the beginning of the study none of the subjects had any symptom of diabetes.

The researchers then followed the subjects along with their vitamin D status.

The subjects were divided into three groups based upon this average blood-based vitamin D status. The first group – 10% of the subjects – had vitamin D (25(OH)D) levels in the blood of less than 10 ng/mL. This is considered being deficient in vitamin D.

The second group had vitamin D levels below 20 ng/mL – considered insufficient. Nearly 52% of the subjects were insufficient in vitamin D.

The third group had what the researchers considered as sufficient levels of at least 20 ng/mL 25(OH)D vitamin D in their bloodstream (although many experts believe these levels are still not sufficient for health). About 38% of the test subjects had these levels or higher.

The deficient group had almost three times the incidence of type 2 diabetes at the end of five years compared to the “sufficient” group. Nearly 16% of the deficient group contracted type II diabetes, while only 5.4% of the “sufficient” group contracted diabetes after five years. 10% of the insufficient group (between 10 and 20 ng/mL of 25(OH)D in the blood) had diabetes after five years, almost double that of the “sufficient” group.

The researchers eliminated obesity, hypertension and other known diabetes risk factors from the results.

The researchers concluded that:

“The current prospective study suggests that vitamin D metabolism may play a role in Type 2 Diabetes pathogenesis independently of known risk factors.”

Vitamin D and blood sugar link

This comment above is significant because the relationship between vitamin D and glucose and/or insulin metabolism has been relatively unknown. What is now becoming evident is that vitamin D is indeed linked to diabetes and glucose metabolism.

The research was led by Dr. James Meigs, a Medical Doctor and Associate Professor of Medicine at Harvard Medical School. Dr. Meigs is a leading researcher in the areas of type 2 diabetes and metabolic syndrome. In a previous study by Dr. Meigs and associates, it was determined that those with lower vitamin D status had biomarkers consistent with insulin resistance.

Type 1 Diabetes and vitamin D

Research from the Ankara Dişkapi Children’s Research Hospital in Turkey found that type 1 diabetes. They also found that insulin medication requirements are linked to vitamin D deficiency.

The researchers tested 100 patients with type 1 diabetes who were between 5 and 20 years old. The patients were tested for levels of vitamin D and its related metabolites and nutrients along the vitamin D pathway (serum calcium, phosphorus, alkaline phosphatase, parathyroid hormone, 25-hydroxyvitamin D (25OHD), and 1,25-dihydroxyvitamin D).

The research found among the diabetes patients that 71% were either vitamin D deficient or had insufficient levels of vitamin D in the body – as measured by serum 25OHD. Only 29% had normal levels (above 10 ng/mL) of 25OHD.

In addition, those patients with less than 10 ng/mL of vitamin D (serum 26OHD) required significantly more insulin than those patients who had serum 25OHD levels over 10 ng/mL. This indicated clearly that diabetes severity was directly associated with vitamin D availability in the body.

The researchers tested the patients over the next year, and found the results consistent.

The research, led by Dr. Ozgul Thnc, concluded that vitamin D plays “an important role in the glucose/insulin metabolism.” Their findings were clear: “We found a significantly higher insulin requirement in type 1 diabetes mellitus children with decreased serum 25OHD levels and decreased insulin sensitivity.”

Insulin sensitivity is related to the cells readily accepting insulin, which escorts glucose into the cell. When cells become less sensitive to insulin, the bloodstream is flooded with unabsorbed glucose, creating high blood sugar levels. This in turn creates numerous health problems, ranging from obesity to heart disease.

While only a few foods contain vitamin D and vitamin D can be supplemented, sun exposure is an inexpensive and healthy way to maintain consistent vitamin D levels, assuming the season and location.

Find out more about the health benefits of sunshine and vitamin D:

 

REFERENCES:

Lim S, Kim MJ, Choi SH, Shin CS, Park KS, Jang HC, Billings LK, Meigs JB. Association of vitamin D deficiency with type 2 diabetes in high-risk Asian subjects. Am J Clin Nutr. 2013 Mar;97(3):524-30.

Liu E, Meigs JB, Pittas AG, McKeown NM, Economos CD, Booth SL, Jacques PF. Plasma 25-hydroxyvitamin d associated with insulin resistant phenotype in nondiabetic adults. J Nutr. 2009 Feb;139(2):329-34.

Thnc O, Cetinkaya S, Kizilgün M, Aycan Z. Vitamin D status and insulin requirements in children and adolescent with type 1 diabetes. J Pediatr Endocrinol Metab. 2011;24(11-12):1037-41.