Doubling Vitamin D Level Could Add Two Years to Life Expectancy
In the September, 2011 issue of the European Journal of Clinical Nutrition , W. B. Grant of the Sunlight, Nutrition and Health Research Center in San Francisco concludes that doubling one’s serum level of vitamin D might increase life expectancy by an average of two years. Dr. Grant utilized epidemiologic studies, randomized controlled clinical trials and meta-analyses for his review. His methodology involved identifying major diseases for which having high vitamin D levels was associated with a reduction in incidence and mortality, determining the strength of evidence and vitamin dose-mortality rate relations for each type of disease, obtaining World Health Organization mortality rates for the year 2004 for various regions, determining mean serum vitamin D levels for six regions and calculating the mortality rate reduction for each region.
Conditions and diseases responsive to vitamin D that account for over half of the world’s mortality include cancer, cardiovascular disease, diabetes, tuberculosis, and respiratory diseases and infections, while Alzheimer’s disease, falls, meningitis, Parkinson’s disease, multiple sclerosis, maternal sepsis and pre-eclampsia were determined to be responsible for 2 to 3 percent. Dr. Grant calculated that increasing serum vitamin D from 54 to 110 nanomoles per liter would lower the mortality rates of diseases that are sensitive to vitamin D by approximately 20 percent. When deaths from all causes over a given period were considered, doubling vitamin D would result in 7.6 percent fewer deaths for African females and 17.3 percent fewer among European females, with males having reductions that averaged 0.6 percent less. The total increase in life expectancy associated with doubling the population’s vitamin D level averaged two years.1
Dr. Grant notes several ways to raise serum vitamin D, including food fortification, supplementation and increased ultraviolet B exposure.
“No matter what combination of approaches might be undertaken in different countries, there would have to be educational campaigns to encourage compliance, as well as selective monitoring of serum 25-hydroxyvitamin D levels to determine the efficacy of the programs,” he concludes.
Vitamin D as a Modulator of Autoimmunity and Intestinal Permeability
Vitamin D is a very important regulator of immune function. Deficiency of vitamin D has been associated with development of intestinal permeability and autoimmune disease.2
“Vitamin D deficiency may compromise the mucosal barrier, leading to increased susceptibility to mucosal damage and increased risk of IBD (inflammatory bowel disease).” 3
“There is growing appreciation of the importance of the pleiotropic hormone vitamin D in the development of tolerance, immune system defenses, and epithelial barrier integrity.”4
“These observations suggest that vitamin D plays a critical role in mucosal barrier homeostasis by preserving the integrity of junction complexes and the healing capacity of the colonic epithelium.”5
There is also growing evidence that vitamin D regulates immune function and acts on the immune system in many ways to suppress systemic inflammation:
“The common denominator that rises from these studies is that vitamin D affects the immune system at many levels and by a number of mechanisms. It takes part in the genetic regulation of cytokine production, VDR expression and affects important biological processes by which these cells interact. On the whole, vitamin D confers an immunosuppressive effect.” 6
The ability of vitamin D to suppress systemic inflammation may be a possible mechanism for the decreased risk of several chronic diseases and the extended lifespan observed in the above study.
1. European Journal of Clinical Nutrition 65, 1016-1026 (September 2011) | doi:10.1038/ejcn.2011.68
2. The Journal of Immunology, 2005, 175: 4119-4126
3. Am J Physiol Gastrointest Liver Physiol. 2008 Jan;294(1):G208-16
4. Potential mechanisms for the hypothesized link between sunshine, vitamin D, and food allergy in children. J Allergy Clin Immunol. 2010 Aug;126 (2):217-22
5. Novel role of the vitamin D receptor in maintaining the integrity of the intestinal mucosal barrier. Am J Physiol Gastrointest Liver Physiol. 2008 Jan; 294(1):G208-16
6. The Journal of Immunology, 2005, 175: 4119-4126