Several plant oils and nutritional supplements have been promoted as natural sunscreens. How much skin protection do they provide? What are the safest and most effective sunscreen ingredients?
“I’ve been seeing articles about making your own natural sunscreen from plant oils. Are these really enough to protect my skin from UV damage? What about supplements that are supposed to act as internal' sunscreen?”
Thanks to extensive messaging campaigns from the American Academy of Dermatology and others, most of us are well aware of the dangers of UV radiation. Unprotected exposure to the sun's rays can lead to potentially lethal skin cancers, as well as accelerated aging. But before I dig into Anna's question about skin protection, let me take this opportunity to dispel a couple of dangerous skin cancer myths.
Skin cancer does not just affect fair-skinned people. People of all skin colors can get skin cancer--and skin cancers in Black and Hispanic people are more likely to go undiagnosed until they are in a late stage, when treatment is more difficult.
Another common misperception is that skin cancers only form on areas of the body that are exposed to sunlight. When checking your skin for suspicious moles or spots, be sure to check the soles of the feet and other areas of the body that are typically covered.
Finally, if you do find a suspicious mole, you shouldn't wait until your next annual physical to get it checked. Melanoma, which is the most deadly form of cancer, can become life-threatening in as little as six weeks.
Skin cancer does not just affect fair-skinned people. People of all skin colors can get skin cancer.
Are chemical sunscreens safe?
Covering your skin with clothing or shading your face with a hat can offer protection from the sun's rays. For skin that's regularly exposed to the sky, diligent application of sunscreen is the best protection. But recent studies have raised concerns about the chemical sunscreens that are most widely used in commercial sunscreen products.
A study published in JAMA (The Journal of the American Medical Association) in 2020 found that the chemicals found in these products (avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate) are absorbed into the body when applied to the skin. After three weeks of daily sunscreen use, these compounds could be detected in the blood of subjects. Although we don't know for sure what the consequences of having these chemicals in our blood might be, there are concerns about effects on the endocrine system. It's quite clear, however, that these chemicals are harmful to ocean life. (Just this year, Hawaii banned the sale of chemical-based sunscreens in an effort to protect their coral reefs.)
In fact, the amount of chemicals that can be absorbed from sunscreen far surpasses the threshold that would require the manufacturers to do additional safety testing. But because sunscreens had been approved for sale long before these rules were established, they've been given a bit of a pass. After studies documented the rates of absorption, the FDA asked the manufacturers to do additional safety testing but has allowed the products to remain on the market for the time being.
In the fallout from all of this, it's not suprising that interest in more natural sunscreens has grown.
Simply basting yourself in olive oil is not sufficient to protect your skin.
Will coconut or olive oil protect your skin?
Some in the "natural beauty" industry have advocated the use of extra virgin coconut or olive oil as a natural sunscreen. And in fact, these oils do have some capacity to filter UV rays. One study calculated an SPF rating of about 7 for both olive and coconut oil. Lavender and almond oil had an SPF closer to 5. (The recommended level of protection is 30). This study also only measured protection against UVB rays. Subsequent research that looked at both UVA and UVB rays estimated the level of UV protection from natural plant oils to be far lower.
So, simply basting yourself in olive oil is not sufficient to protect your skin. But what about nutritional supplements that claim to protect your skin from the inside?
Nutrients that protect against sun damage
Certain nutrients, including vitamin C, E, and various carotenoids, do appear to reduce or repair some of the cellular damage caused by sun exposure. Let this be yet another great reason to include a broad range of colorful fruits and vegetables in your diet. The antioxidants they contain may help keep your skin healthy and youthful.
There are also some plant compounds that have been found to offer modest protection against ultraviolet damage when taken as an oral supplement, including one from cocoa and another from a specific fern found in Central and South America. Although these types of supplements could be used in conjunction with a topical sunscreen, they would not replace it.
The safest and most effective sunscreens
Clothing and hats can provide a very effective shield against the sun. Although all cloth will give you some protection, you can buy clothes with SPF ratings of 30 or higher. These would be good choices if you're going to be out in direct sunlight for extended periods of time.
For skin that you can't or don't want to cover, mineral-based suncreeens that include zinc or titanium oxide provide very effective protection from the sun's harmful rays and do not have the same safety concerns as the chemical based sunscreens. Be sure to apply them to all exposed skin and reapply every few hours, especially if you are swimming or sweating.
Does sunscreen cause vitamin D deficiency?
Finally, keep in mind that an effective sunscreen will also hinder the natural formation of vitamin D in your skin. Some have questioned whether over-zealous use of sunscreen could lead to vitamin D deficiency.
We get some vitamin D from our diet. Oily fish and eggs are natural sources of vitamin D. Cereal, cow's milk, some nondairy alternatives are often fortified with vitamin D. Vitamin D supplements are also an option, especially during the winter months, when the sun is not strong enough to stimulate vitamin D production in the skin.
During the sunnier months, you could meet your daily vitamin D requirements from just a few minutes of unprotected sun exposure.
During the sunnier months, you could meet your vitamin D requirements from just a few minutes of unprotected sun exposure -- without undue risk of sun damage. But the exact amount varies according to the time of year, your skin tone, location, weather, what you're standing on, and even the amount of smog in your location.
Researchers at the Norwegan Institute of Air Research have put together a fun little calculator that will estimate how long you'd need under various conditions. For example, standing in my backyard in Baltimore, Maryland, at noon on a sunny day in May, it would take me 25 minutes to get a sunburn but only 7 minutes to get my dose of Vitamin D.
After my 7 minutes are up, however, I'll be applying a mineral based sunscreen to any exposed skin and making a big salad for lunch.