Vitamin D Deficiency in Winter

01/19/2016

Healthy Living - January 19, 2016
Amy Movius, MD
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Vitamin D has received a lot of press in recent years for its health benefits. Low levels have been associated with numerous health problems including bone disease, multiple sclerosis,Type 2 diabetes, depression, dementia in the elderly, severe asthma in kids, and some types of cancer. Although association isn’t causation, and research doesn’t support Vitamin D supplementation as a panacea for these problems, maintaining normal levels and avoiding Vitamin D deficiency is a good idea. Except in very extreme cases, vitamin D deficiency is generally “silent” so you can be deficient without knowing. 

Vitamin D can be obtained in three ways:
         1.  Skin exposure to sunlight
         2.  Some foods (but not many)
         3.  Vitamin D supplementation

Sun exposure is by far the more efficient way to get Vitamin D.  When skin reacts with sunshine, Vitamin D is produced, and when the body has made enough it simply turns off production. Light skin produces Vitamin D more easily than dark skin. A fair skinned person who receives sun exposure a mere 10-15 minutes a few times a week can easily meet their Vitamin D needs, so sunblock use does not need to be compromised. Getting enough Vitamin D from diet alone can be more challenging. There are a few fatty fish (salmon, mackerel, swordfish) that contain enough to meet daily requirements.  Some other fish contain lesser amounts and there are fortified foods such as cereal and milk. Consuming these fortified food for breakfast can be a way to get some dietary vitamin D regularly. Lastly, taking supplements containing Vitamin D is also an option.

Certain people are at more risk of Vitamin D deficiency including:

1.     Those over 50 years old
2.    Dark Skinned persons
3.    Inhabitants of Northern Climates (i.e. the entire Maine populace)
4.    People with malabsorption (s/a celiac disease, crohn’s disease, cystic fibrosis)
5.    The obese/overweight (fat cells “trap” Vitamin D making it unavailable for use)
6.    Strict vegans
7.    Breast fed infants

As stated above, deficiency of Vitamin D - also known as the “sunshine vitamin” - in Mainers in the wintertime is hardly unexpected since low light and cold temperature drastically limit our sun exposure from about November through March.   In fact, a study done at UMO in 2005 tested vitamin D levels in 23 otherwise healthy “low risk” teenage girls in both September and March.  They found, on average, a nearly 30% decrease in Vitamin D levels from September to March which resulted in nearly half of them (11/23) being deficient in the wintertime.

Given our climate, it is entirely reasonable for many Maine natives to use Vitamin D supplementation in the winter months. The Institute of Medicine RDA (recommended daily allowance) for adults up to 70 yrs. is 600 IU.  This increases to 700 IU for those older than 70, and 400 IU for younger children.  Supplementation is usually in the form of Vitamin D2 or D3, with D3 being more common. Supplements up to 1000 IU are easily found.  Though Vitamin D supplementation is considered quite safe, there is potential harm in taking “mega doses” so the Institute of Medicine recommendation is that daily dosage does not exceed 4000 IU. Lastly, there are some health issues and medications that Vitamin D supplementation may impact, so discussion of Vitamin D supplements with your provider is always a good idea.  


References:  

1.  www.webmd.com Vitamin D Deficiency
2.  Adolescent Girls in Maine Are at Risk for Vitamin D Insufficiency.  Sullivan et al, Journal of the Academy of Nutrition and Dietetics, June 2005