Healthy Living: Which Sun Screen is Best? 

By- Dr. Joan Marie PellegriniGiven Chris Ewing’s weather forecast tonight, it may be a bit hard to fathom needing sun screen anytime soon. However, we are all hoping for a great, sunny summer. Since summer is only a few weeks away, this would be a good time to review some facts about sunscreen.First, let’s review what SPF means. SPF stands for Sun Protection Factor and it is calculated in a rather complex way. There are two types of UV rays: UVA and UVB. SPF refers to protection from UVB. UVA is the type of ray that causes aging of the skin and sunscreen does not protect us well against this type of UV ray. UVB is the type that causes burning and is the type that is absorbed by most sunscreens. Also, there is no linear relationship to the SPF number and how much UV rays are blocked. SPF 15 blocks 93% of the rays and SPF 30 blocks 97% (these numbers are from a WebMD article that I have listed below). Guidelines recommend and SPF of 15 or higher. As you can see from the numbers above, buying a higher SPF screen does not necessarily give you much more protection. More chemical must be added to the screens to obtain the higher SPF and there are some experts who feel that the amount of chemicals in the “very high” SPF screens (over 30) may actually lead to more skin cancers (a very controversial topic). These types of sunscreen protect us because they absorb the UV light. Other sunscreens protect against both types of UV because they provide a physical barrier to block UV rays and usually contain zinc or titanium. They are also heavier and more obvious on the skin (think of the white paste that skiers use on there nose and lips). The WebMD article and the EPA article referenced at the end of this article list which ingredients protect against which type of UV ray.Next, let’s review how the screen is supposed to be applied. Sun screen should be applied to all skin because most summer-weight clothes do not fully protect the skin against the damaging effects of UV radiation. Also, sunscreens that absorb light need to be applied at least 30 minutes before sun exposure because they must be given time to be absorbed into the skin. If you are using one of the sunscreens that provide a physical barrier (they contain zinc or titanium) then you can apply it just before going outside. You will need more than “just a dab” of any of the sunscreens. Sunscreen needs to be applied liberally and often. Therefore, buy a sunscreen that you will not mind using and one that will be easy to apply. The “best” sunscreen doesn’t do you any good if it never gets used.What about vitamin D deficiency? There is some concern that the widespread use of sunscreen may be leading to our widespread vitamin D deficiency however this is quite controversial. I think it is safe to say that the vast majority of national guidelines and experts recommend using sunscreen in an effort to reduce skin cancer rates. If you and your doctor are concerned about your vitamin D level, then it is a pretty simple and safe measure to change your diet to increase your vitamin D intake or to add a vitamin D supplement.Some miscellaneous facts about sunscreen: If you find a sunscreen in your cabinet and you cannot remember when you bought it, it probably is best to throw it away and buy new sunscreen. The active ingredients in the sunscreen may become inactive after 2-3 years. “Water resistant” in a sunscreen means that it will last longer in wet conditions. However, it too needs to be reapplied throughout the day (every 2-3 hours). Sunscreens that contain antioxidants offer advantages for skin healing after injury from the harmful effects of the sun.So, to answer the question of which sunscreen is best: buy the sunscreen that is at least SPF 15 and don’t worry about buying the highest SPF you can find. Make sure you get a sunscreen that is easy to apply. If you have a problem with acne, there are sunscreens made specifically for the face that are not so comedogenic (tending to clog the pores). Wear other protective clothing such as hats and sunglasses and remember that sunscreen does not protect against all of the sun’s damaging UV rays. Don’t forget to reapply. These two articles are excellent resources: article addresses the concern of vitamin D levels when sunscreen is used frequently: