The sun is our most common source of
vitamin D
since it’s rarely found in foods. In fact, when exposed to ultraviolet B (UVB) rays, our skin produces vitamin D naturally.
Yet, about 35% of adults in America have a vitamin D deficiency.
And that’s a problem since vitamin D is important for strengthening and maintaining bones, supporting a healthy immune system, and breaking down glucose in the body, says David J. Leffell, MD, chief of Yale Medicine Dermatologic Surgery and professor of dermatology at Yale School of Medicine.
Here’s how to make sure you’re getting enough of it from the sun.
“It does not take excessive amounts of sun to get a healthy dose of vitamin D. It would be possible to get adequate vitamin D with limited exposure to your arms and legs for 10 to 15 minutes two to three times a week
,” says Susan Massick, MD, a dermatologist at The Ohio State University Wexner Medical Center and associate professor of dermatology in the Ohio State College of Medicine.Several factors affect UVB exposure and vitamin D production, including:
However, you should avoid prolonged sun exposure, which is about 10 to 30 minutes for fair skin, because UVB rays also cause sunburns and photodamage, increasing the risk of skin cancer, says Massick.
Therefore, protect your skin by always using sunscreen or wearing protective clothing when outside — even in the winter. However, sunscreen does not block UVB rays perfectly, says Leffell. Therefore, it can prevent sunburn without compromising the body’s vitamin D production.
Vitamin D supplements are generally recommended for the following cases:
Talk to your primary care provider before taking any supplements to discuss the recommended amount of supplementation.
You can generally get an adequate amount of vitamin D by spending time in the sun for about 15 minutes several times a week. However, skin color, geographic location, altitude, and time of day affect your UVB exposure and vitamin D production.
If you have a darker skin tone,
vitamin D deficiency
, or certain health conditions that affect your absorption or production of vitamin D, you can take supplements to meet the daily recommended allowance for your age.
“You certainly do not need prolonged and frequent sun exposure for the sake of vitamin D,” Massick says. “When in doubt, get additional vitamin D through your diet rather than increasing your time in the sun,” since the increased risk of skin cancer isn’t worth the minimal extra amount of vitamin D you may gain.