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Does Sunscreen Block Vitamin D?

Sunscreen DOES block vitamin D.

It is a fact that for most people, sun exposure is the primary source of vitamin D.  UVB rays are absorbed through the skin, which is then converted to vitamin D.  It is a fact that most effective sunscreens block the skin's absorption of UVB rays.  If sunscreen is blocking the skin from absorbing its primary source of such an essential vitamin should you stop using it?  Most medical professionals, especially those specializing in dermatology, urge consumers to the contrary.

IMPORTANCE OF VITAMIN D

Vitamin D is essential for bone health.  Vitamin D promotes calcium absorption and assists in maintaining adequate phosphate concentrations.  Recent studies have linked vitamin D to aiding in the prevention in many forms of cancer.  Vitamin D deficiency has been associated with increased risks of falls and fracture.  More severe cases are linked to diabetes, autoimmune diseases, and even death.  Though vitamin D can be obtained through food sources such as fish, eggs, fortified milk, and cod liver oil, the primary source of vitamin D for most is sun exposure.

CONTRADITORY EFFECTS OF SUN EXPOSURE

Excessive exposure to sunlight is known to have deleterious effects on the skin.  UV radiation is responsible for the sun's visible effects on the outermost layer of the skin and plays a key role in the development of skin cancer.  UV radiation also responsible for the synthesis of vitamin D.  Because the UV process leading to DNA damage and for vitamin D photosynthesis are virtually identical, the unfortunate fact is that sun exposure has both harmful and beneficial effects.

The contradictory indications of sun exposure and vitamin D effects have sparked the debate that preventing sun exposure through avoidance or sunscreen with the goal of preventing skin damage may at the same time cause vitamin D deficiency.

A LITTLE BIT OF SUNSHINE GOES A LONG WAY 

A 2009 study conducted by researchers at Albert Einstein College of Medicine of Yeshiva University released findings that US children are indeed suffering from some level of vitamin D deficiency.  In a study of over 6,000 children, the researchers found the seven out of ten had low levels of vitamin D.

Michal L. Melamed, assistant professor of medicine and of epidemiology & population health at Einstein, and research lead, makes the following recommendation for parents,   "it would be good for them to turn off the TV and send their kids outside. Just 15 to 20 minutes a day should be enough. And unless they burn easily, don't put sunscreen on them until they've been out in the sun for 10 minutes, so they get the good stuff but not sun damage."

Though the message that sun exposure is harmful and sunscreen is a necessity is loud and clear, it does not mean that all sun exposure should be condemned.  The key to finding the answer is balance.  The harmful effects from UVB rays are experienced from excessive sun exposure.  For those not sun restricted for health reasons, a sensible diet including foods that contain vitamin D and a short walk in the park on a sunny day a few times a week without sunscreen may be enough to provide adequate levels of vitamin D.

Life is all about balance.