9 Factors That Are Affecting Your Vitamin D Level

Spotlighting the nine factors that can affect your vitamin D level.

Figuring out all the factors that can affect a person’s vitamin D levels is complicated.

You can get the vitamin from food (as few foods are natural sources of vitamin D), or by taking supplements (many doctors recommend taking 800 IU of vitamin D 3 a day). But vitamin D is also produced by the body in a complex process that starts when the rays in the invisible ultraviolet B (UVB) part of the light spectrum are absorbed by the skin. The liver, and the kidneys, are involved in the steps that eventually result in a bio-available form of the vitamin D that the body can use.

A review paper about the many factors influencing a person’s vitamin D levels appeared earlier in ‘Acta Dermato-Venerologica’, a Swedish medical journal. We don’t have room to cover every factor discussed, so we selected nine that are interesting, important, or both:

1 The latitude where you live.

At higher latitudes, the amount of vitamin D-producing UVB light reaching the earth’s surface goes down in the winter because of the low angle of the sun.

In Boston, for example, little if any of the vitamin is produced in people’s skin tissue from November through February. Short days and clothing that covers legs and arms also limit UVB exposure.