How much vitamin D can you get from the sun this summer? July 01 2015
Excerpts from How Stuff Works by Maria Trimarchi
How Your Body Converts Sunlight Into Vitamin D
Your body is able to produce its own vitamin D3 when your skin is exposed to the sun's ultraviolet rays, specifically ultraviolet (UVB) radiation. When UVB rays hit your skin, a chemical reaction happens: Your body begins the process of converting a prohormone in the skin into vitamin D. In this process, a form of cholesterol called 7-dehydrocholesterol (7-DHC), naturally found in your skin, absorbs the UVB radiation and gets converted into cholecalciferol. Cholecalciferol is the previtamin form of D3. Next, the previtamin travels through your bloodstream to your liver, where the body begins to metabolize it, turning it into hydroxyvitamin D, which is also known as 25-hydroxyvitamin D or 25(OH)D. The kidneys then convert the 25(OH)D into dihydroxyvitamin D, also called 1,25-dihydroxyvitamin D or 25(OH)2D -- this is the hormone form of vitamin D your body can use [sources:The George Mateljan Foundation, Holick].
It's estimated that we get -- or should get -- more than 90 percent of our vitamin D from casual, daily sun exposure [source: Holick]. Let's figure out what casual, daily sun exposure means. There are variables, which we'll talk about, but some studies have found that between five and 30 minutes of sun exposure to your unprotected face, arms, legs or back between the hours of 10 a.m. and 3 p.m. two to three times every week is enough for your body to produce all the D3 it needs [source: National Institutes of Health - Office of Dietary Supplements].
Under picture-perfect conditions, the human body is able to produce as much as 10,000 IU to 20,000 IU of vitamin D3 in just 30 minutes [source: The George Mateljan Foundation].
When NIH advises unprotected sun for 30 minutes between the hours of 10 and 3, what skin color are they referring to? And how strong is the sun?
SunFriend measures the intensity of the sun and you put in your skin color. You can actually see how much UV you are accumulating, adding a very scientific layer to "guessing" how much sun will be enough. If the sun is at very strong, say a UV Index of 10 or 11, you will need much less time than if the sun is at a UV Index level of 2 or 3. SunFriend measures UV through clouds as well.
Summer is the best time to optimize your UVB exposure which gives you vitamin D. But year round sun exposure gives you endorphins and nitric oxide, all essential to overall wellness and better moods.
SunFriend is perfect for teaching kids early habits for sun balanced sun exposure. Vitamin D deficiency early on not only effects how strong and fast bones grow, but can be a precursor to hundreds of diseases including over 100 cancers, diabetes, MS, osteoporosis, alzheimer's, and new diseases are being linked every day.
Sunburn is always a concern. There is no reason you should get sunburned while you are reaping the healthier benefits of the sun. SunFriend is designed to help you optimize your sun exposure before you burn. SunFriend requires no harsh chemicals either.