Vitamin D Blood Levels Shown to Influence Insulin Health

by | Apr 9, 2013 | 2012, Diabetes, Pancreatic Health, Vitamin D - General

Written by Greg Arnold, DC, CSCS. In a study of 494 workers, those with highest vitamin D levels had 13.8% lower fasting insulin levels and 17.3% lower indication of insulin resistance  than those in the lowest vitamin D group.

According to the latest statistics from the Department of Health and Human Services, there are 25.8 million Americans (1 in 12 citizens) with diabetes, 90% of which have type 2 diabetes. Type 2 diabetes is a major cause of heart disease and stroke, is the seventh leading cause of death in the United States, and costs our healthcare system $174 billion per year (1).

Many risk factors exist for type 2 diabetes, including excess body weight, HDL cholesterol levels <35 mg/dL,  triglycerides >250 mg/dL, blood pressure >140/90 mmHg (2). Now research suggests vitamin D deficiency to be another risk factor. Research reviews in 2007 (3) and 2011 (4) showed that low vitamin D blood levels increase the risk for type 2 diabetes. When it comes to insulin resistance, a precursor to type 2 diabetes, however, research has yet to find a link to vitamin D blood levels. Now a new study out of Japanese (5) may have an answer.

In the study, 494 workers in Japan aged 20 to 68 (284 men, 210 women) provided blood samples and dietary information on consumption during the previous month of 56 food items, beverages and 9 dishes listed in the Standard Tables of Food Composition in Japan (6). The subjects were divided into four groups based on their vitamin D blood levels (<48.7 nanomoles/Liter, 48.8-67.6 nmol/L, 67.6-79.8 nmol, and >79.9 nmol/L).

The researchers found a “statistically significant inverse association” between blood vitamin D levels and fasting insulin levels. Specifically, those in the highest vitamin D group had 13.8% lower fasting insulin levels than those in the lowest vitamin D group (28.3 vs. 32.8 picomoles/Liter,p = 0.04). When they looked at a measure of insulin resistance called HOMA-IR (7), those in the highest vitamin D group had 17.3% lower HOMA-IR than those in the lowest vitamin D group (0.91 vs 1.10,p = 0.02). For fasting sugar, researchers found a “suggestive inverse association”, with those in the highest vitamin D group having a 3.3% lower fasting blood sugar level than those in the lowest vitamin D group (p = 0.07).

When suggesting how vitamin D elicits these healthful effects, the researchers pointed to vitamin D increasing the activity of cell receptors for insulin 38, maintaining healthy levels of calcium which positively affects insulin sensitivity39, and affecting parathyroid hormone levels (40) which may reduce insulin sensitivity. (41) They went on to conclude that “[vitamin D blood levels] were inversely associated with markers of insulin resistance among Japanese men and women” and that “our findings add to evidence for the protective role of vitamin D against the development of insulin resistance.”

Source: Pham, N. M., et al. “Serum 25-hydroxyvitamin D and markers of insulin resistance in a Japanese working population.” European journal of clinical nutrition 66.12 (2012): 1323-1328.

© 2012 Macmillan Publishers Limited

Posted April 9, 2013.

Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY.  You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com

References:

  1. “National Diabetes Statistics, 2011” posted on the U.S. Health and Human Services Website.
  2. “Type 2 Diabetes – Risk Factors” posted on the U.S. National Library of Medicine Website.
  3. Pittas AG.  The role of vitamin D and calcium in type 2 diabetes. A systematic review and meta-analysis. J Clin Endocrinol Metab 2007; 92: 2017–2029.
  4. Mitri J, Muraru MD, Pittas AG. Vitamin D and type 2 diabetes: a systematic review. Eur J Clin Nutr 2011; 65: 1005–1015.
  5. Pham NM.  Serum 25  hydroxyvitamin D and markers of insulin resistance in a Japanese working population.  Eur J Clin Nutr 2012 Dec;66(12):1323-8. doi: 10.1038/ejcn.2012.169. Epub 2012 Oct 24.
  6. Science and Technology Agency. Standard Tables of Food Composition in Japan. 5th revised and enlarged edn (Printing Bureau of the Ministry of Finance: Tokyo, Japan, 2005.
  7. Esteghamati A.  Optimal cut-off of homeostasis model assessment of insulin resistance (HOMA-IR) for the diagnosis of metabolic syndrome: third national surveillance of risk factors of non-communicable diseases in Iran (SuRFNCD-2007). Nutr Metab (Lond). 2010; 7: 26.