Could the Sun be Good for your Heart? (no, this is not about Vitamin D!)


imageA recent and fascinating Ted Talk featured dermatologist Richard Weller who talks about the science of UV light and how it affects our health.  With humour and eloquence and simplicity, his talk demonstrates why people do not trust the media’s representation of medical discoveries sometimes.

Although our skin creates Vitamin D from cholesterol when exposed to UV light from the sun, sunlight may give us another unexpected benefit too. New research by his team shows that nitric oxide is a chemical released from relatively enormous stores in our skin.  When UV light interacts with nitrates/nitrites that are concentrated in the skin from green leafy vegetables in our diet, it produces nitrous oxide that in turn circulates into the body and reduces blood pressure, and as Dr. Weller agues, likely reduces our risk for cardiovascular disease.  Nitrous oxide is currently a common medical treatment for heart pain (angina) by causing dilation of blood vessels in the heart (and elsewhere).

Higher blood pressure due to lack of sun exposure may begin to explain why, Dr. Weller says, after adjusting for all other lifestyle risk factors, people who live in more northern geographic areas have more heart disease.

Dr. Weller says he feels conflicted — on one hand as a dermatologist, he is recommending we stay out of the sun and put on sunblock to prevent skin cancer.  On the other hand, his new research shows we may be throwing the baby out with the bathwater! (so to speak).  By avoiding the sun too much, on average, northern populations may be increasing their overall mortality rates.  The mortality rate due to cardiovascular disease (and the related high blood pressure) is vastly more significant than the mortality rate due to melanoma.  When we look at the bigger picture, as we often discover after science vacillates back and forth on an issue, moderation and common sense prevail.  This has nothing to say for the beneficial and natural impacts of sunlight on melatonin and our psyche in our ability to be in health and feel well when we are in the sun and in nature….so what to do?

So as you plan your summer, or vacation in the winter, or other activities like tanning beds/therapy, it is wise to consider risk factors like being more fair skinned, or having a history of skin cancer in the family or being immunodeficient. But perhaps sun exposure shouldn’t be avoided entirely? We are a species evolved to be in the sun, and it isn’t surprising that we may benefit from some sun exposure beyond just vitamin D synthesis (which we can replace, theoretically anyhow, entirely with supplements).

By Gord Grant PhD, RAc