Vitamin Sunshine

With summer coming into full force, it’s an appropriate time to discuss the sun and vitamin D.  While the amount is still being debated, it appears that the daily recommended amount of vitamin D has nearly doubled as compared to previously thought.  And everyone agrees that the best source of vitamin D is that which is released naturally by the skin in response to safe exposure to the sun.  Most people recognize the importance of vitamin D for bone strength in conjunction with calcium, but it also is critical as a precursor to all the other hormones and has recently been recognized as a vital component in reducing the risk of about 16 different cancers.  You heard it correctly -- proper sun exposure is an important for reducing the risk of cancer!

Vitamin D is released by safe exposure to ultraviolet rays from the sun, but excessive ultraviolet exposure has always been linked to cancer, in particular an extremely dangerous skin cancer known as melanoma.  Something else you should know about ultraviolet light is that it is broken into a couple different wavelengths.  UVA is considered the “bad guy” that penetrates the skin more deeply and can cause more damage.  UVB is considered the “good guy” that stimulated the skin to produce vitamin D.  Interestingly, this healthy UVB is low in the morning and evening hours and highest around lunchtime between 10 and 2.  Also, UVB is blocked by glass and most every sunscreen.  Sunscreens reduce vitamin D production by around 99%.  UVA, on the other hand is present all day, does not provide any apparent good for the body and is not blocked by glass and is not always blocked effectively by sunscreen.  Rather than get into a debate about what chemicals you should or shouldn’t look for in a sunscreen, I would rather give you a few more reliable strategies.

Avoiding melanoma does not come from avoiding the sun, it comes from avoiding sunburns.  Studies show that people who spend more time outdoors in the sun without getting burned actually have a decreased risk of melanoma (likely due to vitamin D).  So the best advice would be to get midday sun exposure several times a week without getting burnt.  Likewise, you should avoid full body exposure through use of clothing and be aware that you are still getting the more damaging UVA rays in the morning and evening even on overcast and cloudy days.  If you have plans at the lake or the pool where you will be getting longer exposure, you will want to do some research to find the healthiest and most effective sunscreen and use it.  Have a great summer!