With a forecast full of sunshine, one would think a lack of Vitamin D isn’t a problem. However, for the northern half of the United States, including Missouri, Vitamin D deficiency is a concern.

According to a study by Harvard Medical School, people living north of the 37th parallel do not see enough sunshine to produce Vitamin D in the fall and winter months.

What is the 37th parallel?

The 37th parallel refers to the 37th latitude north of the equator. In the United States, the line stretches from San Francisco to the Texas Panhandle, along the Missouri/Arkansas state line to the northern edge of North Carolina.

In the southern hemisphere, those south of the 37th parallel have less sunlight.

What does the sun have to do with Vitamin D?

Vitamin D is also known as the ‘sunshine vitamin’. When skin is exposed to sunlight, the sun’s UVB rays interact with a protein in the skin, converting it into Vitamin D3, which is the active form of Vitamin D.

Why do those north of the 37th parallel not see as much sun?

During the fall and winter months, the sun is lower in the sky, making UVB rays weaker than they are in the summer. On top of weaker rays, the days are shorter than areas to the south. Both make less sunlight an issue for Vitamin D production.

What does this all mean?

Vitamin D deficiency in the winter months is nothing new, and thankfully it can be a seasonal issue for some. By the time the days grow longer and spring rolls around, all the Ozarks should be out of the woods.

If you are worried about Vitamin D deficiency, speak with your doctor on ways to supplement during the winter months.