As a scientist I have been trained to question a statement, evaluate the facts from multiple sources, and make a judgement based on information at hand. But as I get more and more into the field of applied science, I realize that this is not usually how the general people process information. A lot of people agree with whatever is loud in the media, others tend to believe in their old doctrine without taking into account of new information. I also realize that as a scientist our responsibility is not just to conduct new research and make new discoveries but also to help people understand the new results, and that’s the way to ensure our work makes a difference in people’s lives. So, here’s my humble attempt to address a couple of things close to my heart.
Topic #1: Sunscreen
Prolonged sun exposure damages the skin. We all know that from our own experiences, just look at the older generation who enjoyed sun bathing when they were young and people who live in higher altitude like Colorado. The red tones, deep wrinkles, and dark pigments are the evidence of photoaging. Ultraviolet radiation (UVR) from the sun can penetrate the outer layers of the skin and cause changes in skin cells and even trigger DNA mutation. Over the past several decades there have been numerous studies that demonstrated the benefits of using sunscreen to skin health, such as a four-and-half year study involving over 900 participants published in 2013. Yet some people still hold the belief that all chemicals are bad and refuse to use sunscreen as a protection measure.
Here’s what I know about sunscreen:
1. In contrast to a lot of other over-the-counter (OTC) products for skin care, sunscreen is actually regulated by the FDA. FDA not only regulates the active ingredients used in sunscreen - therefore the safety of those ingredients have been tested extensively, but also the Sun Protection Factor (SPF) that is on the label – the value has to be tested following FDA’s monograph, a standardized testing protocol.
2. There are two types of active ingredients: one acts as a physical shield by deflecting the UV ray, such as titanium dioxide and zinc oxide; the other acts as a chemical shield by absorbing UV ray and changing it to heat through chemical reaction, such as oxybenzone, octinoxate, octisalate and avobenzone. Don’t let the word “chemical” scare you away, check out this blog for a fair comparison of pros and cons.
3. Sunscreen used to be tested for UVB protection only until a couple of years ago when the harm of UVA ray came to light. These days sunscreens should have “broad spectrum” label on it. To indicate protection for both UVB and UVA rays.
4. How to read SPF value, is it the higher the better? The value of SPF indicates the fold of energy it can protect comparing to without protection. So SPF 30 is 30-fold effective, meaning it protects about 97% of UV ray (only 1/30 gets through); SPF 50, therefore protects 98%. There’s about 1.3% difference in their protection power. FDA’s new guidance on product label states that the maximum SPF value on product label is limited to SPF 50+ to avoid misleading consumers.
5. When determining SPF value, certain amount of sunscreen is applied on test skin. So when using it if you skimp on the amount you will not get the full protection. The testing amount is 2mg/cm2. In practical term, there’s shot glass rule, 1oz to cover full body when wearing minimal clothing. And don’t forget to reapply every ~2 hours as the products do break down upon sun exposure and you do sweat and wipe off the product.
6. Physical shade definitely provides good protection from the sun. But keep in mind about the reflection of radiation from the ground and environment. We actually did a study and showed that reflection from sandy beach can causes serious sunburns to people who stayed in the beach umbrella shade without sunscreen.
7. Cool temperature makes people forget about the UV ray from the sun. But the UV index in a clear cold day can be as high as a sunny hot day. This is especially important on a ski trail, with the strong reflections coming from the ground.
Topic #2: GMO, to be continued…