Winter Storm Remus: Take Care Outside and Inside
Another winter storm, Remus, is traversing the US. More than 175 million people from the Upper Midwest to the interior South and Northwest will have to endure severe cold conditions. Without doubt, people living in these regions will not be exposing much skin for vitamin D synthesis in the skin.
Cold weather is one of the environmental factors contributing to low vitamin D status. Genetics is another factor. Hansen and colleagues report that 55% of African Americans studied in the Health ABC Study were vitamin D insufficient [< 50 nmol serum 25(OH)D3/L]. Age had little effect on vitamin D concentrations but men, those living in Memphis TN, and summer had positive effects on vitamin D status. Depending how far south the Canadian cold front penetrates, even men in Memphis may not be sunning much this week.
Having serum 25(OH)D3 concentrations below 50 nmol/L increases risk of cancer and mortality. Serum vitamin D levels below 25 nmol/L are associated with increased risk of diabetes. Having serum 25(OH)D3 levels below 50 nmol/L is associated with a two-fold increase in heart failure death (versus having levels > 75 nmol/L).
Vitamin D comes in two forms: cholecalciferol (D3) and ergocalciferol (D2). It is more effective to use vitamin D3 than vitamin D2 when supplementing.
If you are living in areas experiencing freezing temperatures, please take care of yourself when moving outside. For your insides, please take care to maintain a healthy serum 25(OH)D3 status.
Hansen JG, Tang W, Brannor PM, Houston DK, Kritchevsky SB, Harris T, Garcia M, Lohman K, Liu Y, de Boer IH, Kestenaum BR, Robinson-Cohen C, Siscovick DS, Cassano PA. Genetic and environmental factors are associated with serum 25-hydroxyvitamin D concentrations in older African Americans. 2015 J Nutr doi: 10.3945/jn.114.202093
Bischoff-Ferrari HA et al. Benefit-risk assessment of vitamin D supplementation. 2010 Osteoporosis International doi: 10.1007/s00198-009-1119-3
Husemoen LLN, Skaaby T, Thuesen BH, Jorgensen T, Fenger RV, Linneberg A. Serum 25(OH)D and incident type 2 diabetes: a cohort study. 2012 EJCN doi: 10.1038/ejcn.2012.134
Liu L et al. Serum 25-hydroxyvitamin D concentration and mortality from heart failure and cardiovascular disease, and premature mortality from all-cause in United States adults. 2012 Am J Cardiol doi: 10.1016/j.amicard.2012.05.013
Heaney RP, Recker RR, Grote J, Horst RL, Armas LAG. Vitamin D3 is more potent than vitamin D2 in humans. 2011 JCEM doi: 10.1210/jc.2010-2230