Strategies for Comprehensive and Effective Sun Protection

The importance of sun protection

The sun provides us many benefits, mainly by helping our bodies synthesize Vitamin D, which is essential to our health and well-being. However, the sun can also be dangerous by causing sunburns and skin cancer. While we can enjoy the sun, we also need to understand how to protect ourselves from the sun. We’re going to start by breaking down the types of sun protection including two types of sunscreen. Then we’ll talk through some sunscreen-free natural sun protection methods.

Two categories of active sunscreen ingredients

Active ingredients of topical sunscreen (i.e. external application to the skin) have two categories. Active ingredient in this case means the ingredient that is actively protecting your skin from the sun.

First there’s chemical filter sunscreens, also referred to as organic filters. No, this doesn’t mean pesticide free, it’s in reference to the chemical structure of the active ingredient! Chemical filters are man-made molecules that absorb into the skin. Once absorbed into the skin, these chemical filters are designed to absorb and convert wavelengths of UV light to heat that’s released from the skin. 

The second category is physical filter sunscreens, also referred to as mineral or inorganic sunscreens. Physical filters originate from minerals. They form a barrier on the skin to reflect and scatter all wavelengths of UV light away from the body. Physical filters can also be referred to as “sunblock” instead of sunscreen. This is due to the material blocking absorption of UV light from the skin.

A summary of common sunscreen ingredients

As we learned about sensible sun exposure previously, both UVA and UVB rays can cause damage to our skin and we need to protect ourselves from both types. Physical filters can protect across the entire UV spectrum, while different chemical filters are needed for different types of protection. Below is a list of the common physical and chemical filters and what types of UV rays they can protect you from. Anything that protects from both UVA and UVB rays is “broad spectrum” protection. Note that these are just some common active ingredients in sunscreens and this list is not all encompassing. Do you have any of these ingredients in your sunscreen?

Physical FilterUVA/UVB Protection	Chemical FilterUVA Protection	Chemical FilterUVB Protection	Chemical FilterUVA/UVB Protection
Titanium Dioxide	Benzophenones (oxybenzone, sulisobenzone)	Para-aminobenzoic Acid (PABA)	Silatriazole
Zinc Oxide	Avobenzone	Cinnamates (octinoxate, cinoxate, octocrylate)	Besoctrizole
Kaolin	Merandimate	Salicylates (octisalate, homosalate)	Bemotrizinol
Talc	Ecamsule	Octocrylene
Calamine	Methyl Anthranilate	Ensulizole

The FDA’s classifications of various sunscreen ingredients

In 1999, the FDA published the list of chemical UV filters that were approved for the GRASE (generally recognized as safe and effective) list. Materials on the GRASE list means any of these could be used in sunscreen formulations as long as they were below the percentage approved by the FDA in 1999. 

In 2019 the FDA published a proposal which highlighted the need for broader safety assessments of ingredients used in sunscreen. Many things have changed in the world since the original assessment date, so it’s time for a new assessment. The FDA divided the active ingredients into three categories: 

1. Category I includes ingredients with sufficient data to remain on the GRASE list. The only ingredients recommended for Category I are Zinc Oxide and Titanium Dioxide. Both of these ingredients are physical (inorganic or mineral) UV filters. 
2. Category II includes ingredients with sufficient data to suggest that the risks of using these ingredients outweigh their benefits. The only ingredients recommended for Category II are para-aminobenzoic acid (PABA) and trolamine salicylate. This means these two ingredients are NOT safe for sunscreen formulations.
3. Category III includes ingredients with insufficient data to support these ingredients remaining on the GRASE list. Category III ingredients are: cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate O, sulisobenzone, oxybenzone, and avobenzone.

Health effects of Category III sunscreen ingredients

There are other studies that we can look to for the effects of the ingredients in Category III. However, it’s important to remember that these studies are NOT enough information for the FDA to make a decision on. We must use our own judgment when reviewing these study results.

1. Oxybenzone (also referred to as benzophenone-3 or BP-3) is one of the most heavily studied chemical UV filters in Category III. Oxybenzone has been found in feces, plasma, urine, and even breast milk. This means the skin absorbs it into the bloodstream after application. Oxybenzone is also a common allergen and can cause reactions in people with sensitive skin. In studies with lab animals, oxybenzone has shown signs of endocrine disruption. In other studies, oxybenzone has been linked to endometriosis in women and worse sperm quality in men. A more recent study has also tied oxybenzone exposure in pregnant women to Hirschsprung’s Disease in newborns, which is an intestinal disease requiring surgery as the only treatment option.
2. Octinoxate (also referred to as octyl methoxycinnamate or OMC) has also been found in blood plasma, meaning that it is being absorbed through the skin into the bloodstream after application. Some studies also demonstrate that octinoxate has endocrine disrupting potential.

The biggest unknown in these studies is the contribution of sunscreen to the levels of oxybenzone and octinoxate in the bloodstream, urine, etc. These two chemicals are not only active ingredients in sunscreen, but are also UV filters in a variety of other cosmetic applications, packaging, found in drinking water, etc. So while we may be able to show some linkage between these chemicals and endocrine disruption, we can’t necessarily say the concentrations in our sunscreen would cause a negative impact on humans. All that being said, because we’re exposed to these chemicals in many different ways and the impact is unknown, I choose to avoid any known exposure routes like sunscreen.

The hazards associated with mineral sunscreens

While the FDA does recognize titanium dioxide and zinc oxide as Category I (still on the GRASE list), it’s important to call out the hazards of nanoparticles, which can be a concern depending on the type of mineral sunscreen you purchase. Titanium dioxide and zinc oxide can both be formed into nanoparticles. Nanoparticles are extremely tiny particles (you would need 10,000,000 nanometers for 1 centimeter!) They can be dangerous, particularly if you inhale them. An advantage of using nanoparticles in sunscreen is that it reduces the whitish residue that never seems to rub in with mineral sunscreens. However, nanoparticles can accelerate skin aging and are suspected to cause serious health impacts because they can cross the blood-brain barrier due to their small size. If you’re choosing a mineral sunscreen, use extra caution with any brands including nanoparticles. 

Non-active sunscreen ingredient concerns

Lastly regarding health impacts of sunscreen ingredients, we can’t only pay attention to the active UV filter ingredient! We also need to pay attention to the other ingredients like fragrances, preservatives, etc. There are many ingredients in a sunscreen so it performs as desired (not sticky, doesn’t leave residue, doesn’t smell bad, etc.) I cannot review all of them here, but there are key ingredients we have talked about before like phthalates, fragrance, parabens, among others that are worth limiting. 

How to protect your skin from the sun naturally

There are more natural ways to protect yourself from the sun if you’d like to avoid sunscreens:

1. The most obvious one is to avoid exposure. The best time to avoid sun exposure is between 10am and 2pm, when the sun will be most intense. You can also check out my Vitamin D blog post for a quick calculation to figure out how long you should be out in the sun at various times of day for the amount of Vitamin D your body needs!
2. If you are going to be outside for any amount of time, wear a hat. Your face is very sensitive and is one of the most common spots to find skin cancer. The best type of hat is a wide brim hat for full protection of the face. I usually opt for a ball cap, and it works pretty well too.
3. If you are going to be outside for any long period of time, wear clothing to protect your skin. Synthetic materials will typically protect your skin best since they block more UV radiation than natural materials like cotton. The color of your clothing can also have an impact. Dark clothing will absorb more UV light and light clothing will reflect more UV light. Moisture-wicking fabrics that keep you dry will be most beneficial so you don’t overheat. Dry fabrics also provide more protection from UV light.
4. Be mindful of your surroundings. You may need to protect yourself sooner in an unfamiliar place. At higher elevations the UV rays are more intense meaning you will burn faster than at lower elevations. Water and snow reflect UV rays significantly which can cause your skin to burn faster as well. 
5. Protect yourself from the inside out based on the foods you consume! This is not to say that once you change what you eat you’ll magically never have to wear sunscreen again. But, I believe that by eating more of the foods listed below and eating fewer ultra-processed foods, you can spend longer amounts of time in the sun without burning. Here are some foods that protect your skin from the sun:
   1. Antioxidants like Vitamin C and Vitamin E. These two best work when found together. These antioxidants are in red and green peppers, kiwi, broccoli, oranges, grapefruit, strawberries, blueberries, sunflower seeds, and currants.
   2. Carotenoids like beta carotene, lutein, and lycopene are also important. These carotenoids are in carrots, tomatoes, peppers, grapefruit, watermelon, spinach, sweet potatoes, apricots, cantaloupe, kale, and mangoes. Beta carotene can help with skin burn prevention due to its ability to scavenge free radicals formed by the sun’s UVA rays.
   3. Polyphenols are naturally occurring antioxidants in green tea and olive oil. Part of the polyphenol group is a specific compound, resveratrol, which is in grapes and red wine as well.
   4. Omega-3 fatty acids which are in fish oil supplements, trout, sardines, salmon, flaxseed, walnuts, and hemp seeds. 

Choosing a sunscreen

If we do want or need sunscreen protection, how do we choose the best option?

1. First I would make a decision between a chemical or physical filter sunscreen. Based on the research, I try to avoid things that have a negative or an unknown effect on my health and the environment. I primarily choose a physical (mineral) sunscreen without nanoparticles for myself. If you rarely use sunscreen or if you hate the white sheen that mineral sunscreens leave on your skin, maybe your decision is different!
2. Next I would determine the sun protection factor (SPF) you require for yourself and/or your family. SPF is “the ratio of the amount of UV radiation causing erythematous reactions (MED – minimal erythemal dose) using a filter to the amount of radiation resulting in the same burn without filter protection.” This means an SPF 2 absorbs 50% of UVB rays, SPF 15 absorbs 93% of UVB rays and SPF 50 absorbs 98% of UVB rays.
3. Lastly, be aware of other ingredients commonly in personal care product formulations that could be harmful outside of the UV filter itself like preservatives, fragrances, etc. 

Some good brands to look into are: Attitude, Badger, Earth Mama, Mad Hippie, Honest, and Crunchi. I’d love to know in the comments below what your go-to sunscreen brands are. Are you planning to make any changes to your sunscreen use after reading this post? Let me know!

If you’d like to keep reading about the impact of various sunscreen ingredients on the environment, there’s an additional section below the sources list.

SOURCES:

• https://www.europeanreview.org/wp/wp-content/uploads/98-112.pdf
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6978633/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7648445/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9652235/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7838327/
• https://setac.onlinelibrary.wiley.com/doi/10.1002/ieam.4411
• https://www.cnn.com/2019/05/17/health/healthy-skin-diet-sunscreen-drayer-food/index.html#:~:text=Sweet%20potatoes%20and%20spinach%20are,%2C%20apricots%2C%20cantaloupe%20and%20kale.
• https://www.culinarynutrition.com/top-foods-for-sun-protection/
• https://blog.bioticsresearch.com/9-foods-with-uv-protective-effects
• https://www.mamavation.com/beauty/best-non-toxic-sunscreens.html
• https://www.federalregister.gov/documents/2019/02/26/2019-03019/sunscreen-drug-products-for-over-the-counter-human-use

Sunscreen ingredients are potentially harmful to more than just humans…

Next I want to talk through potential environmental impacts of sunscreen ingredients. I’m sure we’ve all heard of “reef-safe” sunscreen, especially if we’ve recently taken a tropical vacation or live in a tropical area. But what does that really mean? 

The “reef-safe” sunscreen name is due to the suspicion of many sunscreens impacting coral reefs. Coral reefs are incredibly diverse and support so many functions and species in their environment. To help understand the magnitude of what coral reefs support, consider this statistic. While shallow warm water coral reefs only take up less than 0.1% of the ocean floor they support approximately 1–9 million different species. We don’t know what will happen if a significant amount of coral reefs die or are altered. In recent years, coral reefs have experienced significant decline and bleaching events to an extent that scientists have never seen before. Because coral reefs support so many species, scientists are trying to understand what is causing the significant decline and how we can better protect the reefs. 

Why sunscreen is considered as a contributing factor in coral reef decline

One of the suggested impacts to coral reefs are the UV filters in sunscreens. Tourism is a growing industry and scientists have detected both chemical and physical UV filters in water around the world. Studies have previously shown a correlation between increased tourism and increased concentrations of UV filters in the water. They have seen a 4.4x concentration at the height of the tourist season compared to the months leading up to the primary season. Studies have also estimated approximately 25% of sunscreen applied to someone’s body ends up washing off in the water they swim in. 

Before getting into the potential effects of sunscreen on coral reefs, we first must understand that there are no “standards” when it comes to executing scientific experiments on corals. This means whoever designs the study can determine their own criteria, which makes it difficult to compare one study to another. It also makes it difficult to extrapolate study findings from a laboratory experiment to real-life situations. With that disclaimer, let’s look at study findings for both chemical and physical UV filter effects. 

The environmental concern with chemical UV filters

Chemical (organic) UV filters tend to bioaccumulate in marine life. Bioaccumulation essentially means it builds up over time as the body doesn’t have the right pathways to get rid of the substance. These UV filters have an impact on the endocrine system of various marine life (corals, algae, mollusks, etc.). The endocrine system is what impacts survival, development, and reproduction. Concentrations causing endocrine system disruption are about 10-1000 times greater than most real-life measured concentrations globally. However, there are no existing studies regarding long-term exposure to these real-life lower levels. Long-term studies are still needed to further prove these theories and original findings. 

Coral bleaching, which is usually the primary issue for UV filters, refers to corals losing an important algae called zooxanthellae. This algae is essential for coral to continue to grow. When zooxanthellae depletes it results in color loss or “bleaching” of the coral. Bleaching can be reversed if the exposure is short, but if continuous bleaching events occur it leads to coral death. Chemical UV filters like octocrylene and benzophenone (BP-3) are shown to cause coral bleaching at concentrations 10-100x recent real-life measured concentrations globally. Again, studies are only looking at acute effects and high exposure. These studies don’t give any indications of what is going to occur long-term at low levels of exposure.

There are of course other potential causes of coral bleaching like water temperature and water acidity, both of which are due to global warming. This is presumed to be the primary cause of bleaching. A few areas have enacted bans of certain chemical UV filters due to this research. In 2019, the US Virgin Islands outlawed all imports and sales of sunscreens containing oxybenzone and octinoxate. Thailand, Hawaii, Key West, and Bonaire (an island of the Netherlands) soon followed by banning the same chemical filters. Instead, the islands are promoting physical filter (mineral) sunscreens that use titanium dioxide and zinc oxide. 

The environmental concern with physical UV filters

Although physical UV filters have significantly less data demonstrating negative effects, there are still some concerns that are worth consideration. Since these physical UV filters are designed to block UV radiation, it may have a similar effect in water. If this is true, it could prevent photosynthesis from occurring in corals and other marine life that requires UV light. While titanium dioxide and zinc oxide have been used for years, nanoparticle versions of these compounds are new with limited data. They could also inhibit photosynthesis just as standard titanium dioxide and zinc oxide could. While the effect of nanoparticles on marine life is mostly unknown, nano-titanium dioxide and nano-zinc oxide were found to be toxic to algae just by accumulating on the surface of the organism.

Next steps for analyzing the effect of UV filters on the environment

At the end of the day, a lot more research is needed before we know definitively the impact these various sunscreen ingredients have on the environment. Particularly future research should focus on standardized test methods for corals. Future research should also ensure to look at both marine and freshwater toxicity assessments. Real-life scenarios of a combination of UV filters should also be evaluated, along with a holistic representation of the ecosystem rather than just corals.

As a reminder, many other personal care products also contain UV filters. Even if we are buying the “right” sunscreen, exposure to the same UV filters through other products is likely. Make-up, shampoo, lotion, and other products that typically contain a UV filter. If they get washed off while swimming, they will have a similar environmental effect.