Approximately three-quarters of U.S. teens and adults are deficient in vitamin D, also known as the “sunshine vitamin.” Vitamin D is necessary for maintaining overall health, and it has a direct effect on the bones, brain, heart, muscles and lungs. There are two main sources of the nutrient: sunlight and supplements.
Most of us get plenty of exposure to direct sunlight—maybe even too much—and yet the majority of Americans are deficient. How can this be?
There are a number of factors that can impact vitamin D levels. Here are five reasons you may not be getting enough of this critical nutrient, according to the Vitamin D Council:
#1 Where you live
The closer you live to the equator, the more UVB you’re exposed to. The body uses UVB to make vitamin D, so if you live close to the equator, you’re more likely to have healthy vitamin D levels. Where you live is especially important in the winter, when places like New York, Boston and Edmonton, Canada, get less UVB—and people living there don’t produce much vitamin D at all. Even people in countries like Chile and Argentina can’t produce much vitamin D from April through October.
#2 Time of day
Your skin produces more vitamin D when exposed to sunlight during the middle of the day, when the sun is most intense. However, since the sun is at its strongest from 10 a.m. to 4 p.m., the Skin Cancer Foundation recommends seeking shade during this time—making it difficult to catch needed rays.
#3 Time of year
In many areas of the world, the angle of the sun’s rays during the winter months causes beneficial UVB rays to diminish. During these months, it’s difficult to get enough UVB rays for your body to convert into vitamin D. Some areas of the world, such as Florida, get good amounts of UVB year-round.
#4 Sun protection
Covering up is an important strategy in preventing skin cancer, but the more skin you expose, the more vitamin D you’ll make. Sunscreen can limit vitamin D production, too.
#5 Skin type
The darker your skin, the more melanin you have, a substance that protects against skin damage from UVB rays. Since the body uses UVB to make vitamin D, that means that people with darker skin make less vitamin D per minute than people with lighter skin. A person with very pale to fair “cream white” skin may need only 15 minutes of sun exposure to make vitamin D while someone with brown to very dark brown skin may need up to two hours in the sun. (These numbers will vary widely based on location and time of year and day.)
Other factors
The list of other factors is long: Aging causes vitamin D production to decrease. Being behind glass blocks all UVB rays. Pollution absorbs some UVB rays, making it more difficult to produce vitamin D in polluted areas. A cloudy day means less UVB, which results in less vitamin D. And the list goes on.
0 comments:
Post a Comment