By: Jordyn Cormier May 4, 2016
We all hear about vitamin D’s importance on a regular basis, but do you really know how to make sure you’re getting enough of it? It’s not as simple as just going outside on a sunny day.
For the prevention of the majority of diseases, it’s recommended that blood serum levels of vitamin D 25(OH)D fall between 40 and 60. However, many of us who spend the bulk of our days indoors are incredibly vitamin D deficient. In fact, it is estimated that 40 to 75 percent of the world’s population is vitamin D deficient.
Vitamin D is an unsung hero in the body. It is indispensable in a variety of functions, such as enhancing calcium absorption for bone health, supporting several immune system functions, preventing depression and helping to prevent some forms of cancer and autoimmune disorders. Inadequate levels in the body contribute to overall poor health and can be at the root cause of certain diseases.
Vitamin D can be found in some foods, such as beef liver, egg yolks and cold water fish. However, food-based sources of D are generally a less dense source. They are also an inactive form of the vitamin which must undergo various processes to become activated in the body. On the other hand, vitamin D produced by the sun is highly bioavailable.
Vitamin D is actually a hormone rather than a vitamin. It is for this reason that spending a little time outside with exposed skin is incredibly important, as the sun is one of the most efficient ways to stock up on vitamin D.
Here’s the catch: you can’t make vitamin D anytime you go outside. The sun has to be at the proper angle in the sky, so those of us living further from the equator have limited opportunities to allow our bodies to synthesize vitamin D.
“I have established that in order to produce adequate levels of vitamin D the solar azimuth angle/the angle of incidence of solar radiation should be 45 O < α < 90 O . UVB rays will only penetrate the atmosphere when the sun is above an angle of around 45 degrees from the horizon. A useful observation when you are outdoors is to evaluate the length of your own shadow. If it is longer then you are, you are not producing any vitamin D.” (Dr. Karolina M. Zielinska-Dabkowska, source)
To calculate for yourself, use this azimuth chart. Simply enter data into the table indicating your location and the date, and compute. You’ll get a long and impressive looking list of numbers. Simply glance down the altitude column and find where the number falls between 45 and 90 degrees. Then, take note of the times in the column on the left. These are the only times when your body can produce vitamin D during the day on that particular date (if it is sunny). Otherwise, the rays gets filtered out through the atmosphere and you’ll simply be subjecting yourself to harmful UV rays without the benefit of D synthesis.
Additionally, using sunscreen can block the rays that initiate vitamin D synthesis, so spending 10 minutes in the sun without sunscreen is important. Of course, if you’re going to be outside longer than that, slather up.
Vitamin D is essential for a myriad of functions. While it’s great to get outside whenever you can, supplementing with a quality D3 supplement is important for those of us who don’t live along the sunny equator.