Category Archives: exercise outdoors

Does sunscreen compromise vitamin D levels?

I am somewhat paranoid about my bike riding in the sun as I have had three skin cancer operations. Foolishly, because I am Italian and tan don’t burn, I never felt the need for sunscreen. Not one of my best decisions. As my dermatologist said, “There is no such thing as a healthy tan.” I now lather up big time before riding in the sun.

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Here is the sun rising over Lake Michigan on a morning ride.

Sunscreen can reduce the sun’s adverse effects, but there are concerns that it might inhibit the body’s production of vitamin D. In a new British Journal of Dermatology study, however, investigators recorded an increase of vitamin D in participants during a week of cloudless weather, with very high UV index, even when sunscreens were used properly and prevented sunburn.

Sunlight contains UVA and UVB radiation, and the latter is essential for vitamin D synthesis. Two sunscreens with the same SPF were compared. Sunscreen with a high UVA protection factor enabled significantly higher vitamin D synthesis than a low UVA protection factor sunscreen, likely because it allows more UVB transmission.

The findings indicate that the benefits of sunscreen use can be obtained without compromising vitamin D levels.

“Sunlight is the main source of vitamin D. Sunscreens can prevent sunburn and skin cancer, but there has been a lot of uncertainty about the effects of sunscreens on vitamin D,” said lead author Prof. Antony Young, of King’s College London. “Our study, during a week of perfect weather in Tenerife, showed that sunscreens, even when used optimally to prevent sunburn, allowed excellent vitamin D synthesis.”

You can read more about skin cancer in general and my three skin cancers here.

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Filed under exercise outdoors, regular bike riding, sunscreen, Vitamin D