Vitamin D Deficiency

What causes a vitamin D deficiency?

Do you know your vitamin D level? Do you think that you could be deficient in vitamin D? With plenty of sunshine available, it may surprise you to know that an estimated 1 billion people are deficient or insufficient in vitamin D. This is estimated because undiagnosed vitamin D deficiency is common worldwide.

Limited exposure to the sun

The major source of vitamin D is natural sun, so limiting our exposure to it has the biggest impact on vitamin D deficiency. We have all heard about the dangers of skin cancer and the need for sunscreen to protect us from this disease. Unfortunately, no one discusses the dangers of not getting vitamin D from the sun and ways to compensate for it. Using a sunscreen with SPF of 30 decreases vitamin D synthesis in the skin by more than 95%. Even if you do have some exposure to the sun, the total amount of vitamin D you can produce is affected by the season, time of day, ozone amount, latitude, and number of clouds in the sky. The important thing about using the sun for vitamin D production is to know that less is more. You are better off with short regular exposures to the sun rather than prolonged exposure for many reasons. The process is not as simple as the sun hitting your skin and vitamin D appearing in your blood. What actually happens is that vitamin D3 is first transformed by a process known as hydroxylation in the liver to 25-hydroxyvitamin D3, often written as (25(OH)D3), and then again in the kidney to its active form, 1,25-dihydroxyvitamin D3, written as (1,25(OH)2D3). The level that is checked in your blood is 25-hydroxyvitamin D, often written as 25(OH)D, which includes vitamin D2 and D3. By staying in the sun, you limit this process and can actually get less vitamin D. You also have a lower risk of burning and damaging your skin with short exposures. Getting 10 to 15 minutes of sun exposure a couple of times per week can be enough for many people.

Darker skin

Melanin is what gives skin its color. Lighter skin has less melanin than darker skin. Melanin is able to absorb UVB radiation from the sun and reduce the skin's capacity to produce vitamin D3. People with a naturally dark skin tone have natural sun protection and require at least three to five times longer exposures to make the same amount of vitamin D as a person with a white skin tone.

Reviewed on 6/18/2013

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