Is your Vitamin D Status Optimized to Maintain your Health?
Without dietary supplementation, many people fail to eat enough foods rich in vitamin D or get enough direct sunlight on skin surfaces to maintain optimal serum 25(OH)D levels. With suboptimal vitamin D levels, we can feel tired, be more prone to falls, minor respiratory infections and other non-communicable diseases. Based on abnormalities in bone maintenance and accretion, the Institute of Medicine defined serum 25(OH)D concentrations below 30 nmol/L as deficient and 50 nmol/L as adequate.
Using data from 2000 participants in the Diabetes Prevention Trial, Mitri and colleagues report that low vitamin D status increases the risk of metabolic syndrome. Metabolic syndrome is the name for a group of risk factors that raises your risk for heart disease, diabetes and stroke. It carries a 2-fold increase in cardiovascular complications and 1.5 fold increase in all-cause mortality.
Mitri et al (2014) found a number of metabolic syndrome risk factors increased with decreasing 25(OH)D levels. The average plasma 25(OH)D tertiles were 30, 50 and 75 nmol/L. Also based on nationally representative US data, Guixiang and colleagues reported a reduced risk of death among hypertensive adults with 25(OH)D levels above 73 nmol/L (vs lower levels). These observations using endpoints other than bone health provide evidence that optimal serum 25(OH)D levels may be nearer 75-80 nmol/L than 50 nmol/L.
Based on other nationally representative data (NHANES 2001-2006 and NHANES III data), 16% of Americans have ‘insufficient’ vitamin D concentrations [serum 25(OH)D levels between 30 and 50 nmol/L] and another 8.8% are deficient (< 30 nmol/L). The proportion of the population achieving 75-80 nmol/L is unknown but probably small. According to research from the Longitudinal Aging Study Amsterdam (LASA), vitamin D status remains fairly stable as we age. Vitamin D status is primarily influenced by season; status being lowest in winter. Over the 6 years, 40-43% of the participants from the Netherlands had serum 25(OH)D levels below 50 nmol/L. Again, the percentage maintaining levels nearer 75 nmol/L would be low.
Overall, these studies tell us two things. There is accumulating evidence that maintaining serum 25(OH)D levels approximating 75-80 nmol/L is beneficial. Most people are failing to achieve these targets through diet and sunlight. Did you take a vitamin D supplement today?
Mitri J, Nelson J, Ruthazer R, Garganta C, Nathan DM, Hu FB, Dawson-Hughes B, Pittas AG, and the Diabetes Prevention Program Research Group. Plasma 25-hydroxyvitamin D and risk of metabolic syndrome: an ancillary analysis in the Diabetes Prevention Program. 2014 Eur J Clin Nutr doi:10.1038/ejcn.2013.293
Mottillo S, Filion KB, Genest J, Joseph L, Pilote L, Poirier P, Rinfret S, Schiffrin EL, Eisenberg MJ. The metabolic syndrome and cardiovascular risk: A systematic review and meta-analysis. 2010 J Am Coll Cardiol doi:10.1016/j.jacc.2010.05.034
Guixiang Z, Ford ES, Li C, Croft JB. Serum 24-hydroxyvitamin D levels and all-cause and cardiovascular disease mortality among US adults with hypertension: the NHANES linked mortality study. 2012 J Hypertens doi:10.1097/JHH.0b013e32834e1f0a
Deng Z, Song Y, Manson JE, Signorello LB, Zhang SM, Shrubsole MJ, Ness RM, Seidner DL, Dai Q. Magnesium, vitamin D status and mortality: results from US National Health and Nutrition Examination Survey (NHANES) 2001-2006 and NHANES III. 2013 BMC Med doi:10.1186/1741-7015-11-187
Van Schoor NM, Knol Dl, Deeg DJH, Peters EPAMN, Heijboier AC, Lips P. Longitudinal changes and seasonal variations in serum 25-hydroxyvitamin D levels in different age groups: results from the Longitudinal Aging Study Amsterdam. 2014 Osteopor Int doi:10.1007/s00198-014-2651-3