Type II Diabetes and Insulin Resistance Linked to Vitamin D Deficiency
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 two 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.”
This comment 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.
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.
Written by Case Adams, Naturopath
Lim S, Kim MJ, Choi SH, Shin CS, Park KS, Jang HC, Billings LK, Meigs JB. Association of vitamin D deficiency with incidence of 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 is associated with markers of the insulin resistant phenotype in nondiabetic adults. J Nutr. 2009 Feb;139(2):329-34.