Reviewing Role of Vitamin D in Endocrine Disorders

Revisiting Recommended Vitamin D Intake

Along with the new research connecting vitamin D to endocrine diseases like diabetes, researchers at the University of California, San Diego and Creighton University are challenging the intake of vitamin D recommended by the Institute of Medicine (IOM).

In particular, the researchers believe the current Recommended Dietary Allowance (RDA) for vitamin D underestimates the need by a factor of 10.  

In a letter published in the journal Nutrients, the researchers confirmed a calculation error, noted by other investigators, by using a data set from a different population.2 Cedric Garland, DrPH, who is an adjunct professor at the University of California San Diego’s Department of Family Medicine and Public Health, said his team confirmed findings published by Paul Veugelers from the University of Alberta School of Public Health that were reported October 2014 in the same journal.3

Both of the studies suggest that the IOM substantially underestimated the vitamin D requirements, according to Garland. In a press release, he said the error has broad implications for public health regarding disease prevention and achieving the stated goal of ensuring that the whole population has enough vitamin D to maintain bone health.

The recommended intake of vitamin D specified by the IOM is 600 IU per day through age 70 years and 800 IU per day for those aged older than 70 years. However, according to Garland, these doses are only about one-tenth of those needed to cut incidence of diseases related to vitamin D deficiency.

Vitamin D for Disease Prevention

Another article published in the Journal of Aging and Gerontology suggests that vitamin D may play a vital role in the prevention and treatment of many diseases associated with aging.4

Researchers at Loyola University Chicago Marcella Niehoff School of Nursing (MNSON) reviewed evidence that suggests an association between vitamin D deficiency and chronic diseases associated with aging such as cognitive decline, depression, osteoporosis, cardiovascular disease (CVD), hypertension, type 2 diabetes and cancer.

“There is evidence to suggest that vitamin D can decrease inflammation regardless of disease, diabetes, multiple sclerosis, etc. However, that evidence [comes from] observational studies that looked at associations between vitamin D and inflammation. There are few clinical trials that have tested this effect,” said study co-author Sue Penckofer, PhD, RN, study author and a professor at MNSON.  “Clinical trial evidence about vitamin D preventing diabetes or helping with diabetes blood sugar control is not available.”

For now, it is uncertain if asymptomatic individuals should be routinely screened for vitamin D levels. Due to the lack of prospective clinical trials, it is hard to assess the risks and benefits. 

“Currently, investigators are trying to accumulate the evidence to determine all of this information, particularly since costs of vitamin D can range from $50 to $250 depending on the method used for the test.  That is a lot of money for persons to pay if insurance does not cover it,” Penckofer told Endocrinology Advisor.

References

  1. Oh J et al. Cell Rep. 2015;10(11):1872-1886.
  2. Heaney R et al. Nutrients. 2015;7(3):1688-1690.
  3. Veugelers P, Ekwaru JP. 2014;6(10):4472-4475.
  4. Meehan M, Penckofer S. J Aging Gerontol. 2014;2(2):61-70.