Dr. John Day, Cardiologist

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3 Critical Things to Know About Sunscreen

While there are many things to know about sunscreen, in this article I’ll stick to the three critical issues.

Unfortunately, if you want to be outside much this summer, sunscreen is a necessary evil.  Studies show that being physically active outside may offer far more benefits to your physical and mental health than exercising in a gym.

As a parent of four children, I know just how challenging sunscreen issues can be.  Read on to find out the the three critical things to know about sunscreen so that you can be sun smart.

1. Sunscreen May Not Prevent Skin Cancer.

Growing up, I thought that sunscreen was protecting me from skin cancer.  Unfortunately, I later learned that there are little data from medical studies backing this up.

While faithful sunscreen use may prevent the less dangerous forms of skin cancer, there is no clear proof that it prevents the more deadly forms, like melanoma.

Even though more people are using sunscreen, studies show that melanoma rates have risen 81% in the last 30 years and are continuing to rise at 3% per year.  This ongoing rise has some researchers now questioning if sunscreen actually increases the risk of melanoma.

There could be many possible explanations for this phenomenon.  For example, sunscreen may give people a false sense of security to stay out in the sun longer than they should.  It could also be that many sunscreens don’t block the UVA form of cancer causing sun rays.  Perhaps people are not applying sunscreen evenly or frequently enough.  Lastly, some researchers have even suggested that the vitamin A (retinyl palmitate) in many sunscreens could theoretically increase the risk of cancer.

The only proven way to decrease your risk of skin cancer is to avoid any prolonged sun exposure.  This means staying indoors during peak exposure times (10 am until 4 pm) or covering up with clothing, hats, sunglasses, etc. when outside.

Interestingly, some studies have observed that safe levels of sun exposure may be protective against melanoma.  Perhaps vitamin D somehow blocks melanomas.  Fifteen minutes of direct sunlight is all that many people need to get their daily dose of vitamin D according to the Vitamin D Council.

It is important to know that if you choose to avoid all sun exposure, you need your vitamin D levels checked regularly.  Research from our hospital has shown that low vitamin D levels are associated with heart disease as well as many other medical problems.

2. Don’t Rely on the SPF Number

If you are like me, I always selected the highest SPF number sunscreen I could find.  I somehow imagined that the higher the number, the more protected I was.  Unfortunately, that is not the case.

The SPF number means how much longer you could theoretically stay out in the sun without burning.  For example, an SPF of 15 means that you could stay out 15 times longer without getting a sun burn.

The problem is that SPF only measures the UVB ray blocking ability.  While UVB rays are the main cause of sunburns, UVA rays can penetrate deeper and also cause skin aging and skin cancer.

In one of many studies, European researchers compared 15 sunscreens which were all marketed with the same SPF number.  Here is what they found:

1. The same SPF number does not predict the UVA blocking ability of sunscreen.

2. The same SPF number is not very accurate when it comes to UVB blocking.

What should you do?  The key is to buy sunscreens which are clearly labelled as broad spectrum.  Seeing broad spectrum on the label increases the likelihood that your sunscreen also blocks UVA rays.

When it comes to the SPF number, you want at least a 15.  Anything above 50 is more about marketing than anything else.

Lastly, remember to apply it evenly and regularly.  Regardless of your SPF number, sunscreen should be applied every two hours.

3. Some Sunscreen Ingredients May Be Dangerous

In my youth I never thought much about what was in the sunscreen I was using.  Somehow I figured that it had to be safe or the government would never let these companies sell their products.  Once again, I was wrong.

As discussed above, many sunscreens contain vitamin A or retinyl palmitate.  Retinyl palmitate could theoretically increase the cancer risk.

The spray on sunscreens may pose additional risks.  Besides uneven application of sunscreen, the spray on versions pose a potential inhalation risk.

As convenient as spray on sunscreens are for our small children, it is because of these inhalation risks that we no longer use spray on sunscreens.  Spray on sunscreens with nanoparticles could even present a possible cancer risk.  For children under 6 months, it is best to avoid sunscreen altogether and just keep them covered up when outside.

While the mineral sunscreens, like zinc oxide and titanium dioxide, may offer the best protection with the least risk, there is still some debate in the medical literature about the safety of nanoparticles.  Until these safety issues can be resolved, it is best to avoid sunscreens wth nanoparticles.

Lastly, there are many chemicals in sunscreens, like oxybenzone, which may have estrogen-like effects on the body.  While it is impossible to remember the names of every potentially bad chemical to look for on the sunscreen ingredient list, there is help.  Before deciding which sunscreen to buy, our family checks the Environmental Working Group’s free app to make sure it is safe and effective.

Take Home Message

There is a very fine line between getting enough sun for your vitamin D needs and not getting too much sun that you prematurely age your skin or get skin cancer. In this article, I focussed on the three most critical things to know about sunscreen.

While the right sunscreen can help you be safer outside during the summer, covering up between 10 am and 4 pm is much safer and more effective than sunscreen.

How do you stay sun smart but yet get your vitamin D?  Please leave your comments below so that all may benefit.  I’ll do my best to answer every question posted.