Currently, one often hears and reads about "free radicals" and their harmful effects on humans. Especially in combination with sunscreen, they are said to be particularly dangerous, even carcinogenic. But is this equation really that simple? We'll explain what "free radicals" are all about, how they are formed, and what you should pay attention to.
Contents:
2. When do free radicals form?
3. What does an excess of free radicals lead to?
4. What helps against the formation of free radicals?
5. What are antioxidants and where are they found?
6. Which foods contain many antioxidants?
7. Do sunscreens increase the formation of free radicals?
8. Does a coating of zinc oxide help prevent the formation of free radicals?
9. Summary
What are free radicals?
Free radicals are atoms that have at least one unpaired electron (a negatively charged elementary particle) in their outer shell, making them relatively unstable. They would prefer to "pair" and combine with another electron. If the radical does not find another electron to pair with or something to neutralize it, its reactivity can lead to damage and loss of function in cells, and thus, in the long term, to DNA damage.
What should not be forgotten in connection with free radicals, however, is that the body can also use free radicals. For example, in the context of inflammatory reactions, free radicals have a very specific added value: they help in fighting pathogens. The formation of free radicals is therefore a physiological, i.e., an endogenous process, which should not concern us at first.
When do free radicals form?
The formation of free radicals occurs in normal metabolic processes, for example during respiration, because a lot of oxygen is involved there. Also, during inflammatory reactions, immune cells form radicals that, as described above, can even help our health. However, there are many external influences that increase the formation of radicals. This puts so-called oxidative stress on our cells, which can be harmful to health in the long term. These include especially smoking (with every puff of a cigarette, a large number of free radicals are absorbed), air pollution, chemicals (e.g., pesticides), or UV radiation.
What does an excess of free radicals lead to?
If the body is exposed to too many free radicals, oxidative stress occurs, which can damage cells and tissues, thus promoting diseases. These include cancers, heart diseases, and many more. In addition, aging processes (e.g., of the skin) are accelerated by free radicals.
What helps against the formation of free radicals?
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Avoidance of environmental toxins: Smoking, air pollution, pesticides, and other chemicals provide a concentrated load of free radicals.
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Use of sun protection: The filters in sunscreens protect the skin from UV radiation, which promotes the formation of free radicals.
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Intake or use of antioxidants: These neutralize free radicals. The body partially produces its own antioxidants or processes antioxidants that we have consumed, e.g., through food.
What are antioxidants and where are they found?
Antioxidants are substances that "capture" free radicals by releasing an electron from their outer shell, which pairs with the unpaired electron of the radical, or by absorbing the unpaired electron themselves. In short: antioxidants neutralize free radicals. They are essential in many metabolic processes, repair cell damage, and ensure balance in our bodies.
Antioxidants include:
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Vitamin E (identifiable as tocopherol in the ingredients of a skincare product)
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Vitamin C (Ascorbic acid)
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Trace elements (e.g., zinc, selenium..)
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Carotenoids (including astaxanthin, beta-carotene, etc.)
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Various omega fatty acids
Which foods contain many antioxidants?
You can find a high content of antioxidants in these foods:
- Carotenoids can be found, for example, in carrots, algae, tomatoes, watermelon
- Vitamin C can be found, for example, in broccoli, oranges, berries, and red bell peppers
- Vitamin E can be found in spinach, kale, avocado, and nuts
- Good fatty acids can be found in fish, oils, and nuts
Do sunscreens increase the formation of free radicals?
This question can be answered with a clear NO. On the contrary: As explained above, UV rays can cause the formation of free radicals. If you continuously protect your skin from UV rays with a sunscreen, you reduce the likelihood that UV rays will lead to the formation of free radicals.
However, mineral UV filters, such as zinc oxide or titanium dioxide, contain one or two oxygen molecules, as the name already indicates. For zinc oxide, the mineral filter we use for our sunscreens, a study* was published in 2012 which showed an increased photocatalytic effect of nano-zinc oxide in combination with UV rays in laboratory experiments. It is important to note here that these are in-vitro (i.e., in a test tube) studies that could not be confirmed in-vivo (i.e., in humans). As already mentioned, the human body has many of its own mechanisms to deal with the formation of free radicals, and these cannot be easily simulated in a test tube. In addition, zinc itself is an antioxidant.
Does a coating of zinc oxide help prevent the formation of free radicals?
This assertion has not yet been comprehensively substantiated, as uncoated zinc oxide is primarily used in cosmetics. Uncoated zinc oxide is known for its good skin compatibility, even for sensitive skin types. It is used as a UV filter and is considered safe for use in children, as it remains on the skin surface without being absorbed. Coated zinc oxide is often covered with silicones or other polymers to make the particles appear smaller or to reduce whitening. However, as certified natural cosmetics, we cannot use silicone-coated zinc oxide - and we would not want to. Our UV filter leaves zinc oxide in its natural form and offers high broad-spectrum protection against UVA and UVB rays.
Summary:
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The formation of free radicals is a natural process that can occur in many chemical reactions.
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The body uses the formation of free radicals, for example, to defend itself against pathogens or to induce controlled cell death.
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Endogenous antioxidants or those supplied through food can "trap" free radicals and thus neutralize them.
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Smoking, air pollution, and UV rays can lead to increased absorption or formation of free radicals and should therefore be avoided.
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Sunscreen protects the body from UV radiation and thus also from the formation of free radicals.
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A connection between the mineral UV filter zinc oxide and the increased occurrence of free radicals under UV radiation has not yet been confirmed in humans.
* https://news.mst.edu/2012/05/sunscreen_ingredient_may_pose/
O U R E X P E R T
Dr. med Michaela Hagemann I boep-founder, doctor & 3-time mom
Sources:
Chaudhary, P. et al.: Oxidative stress, free radicals and antioxidants: potential crosstalk in the pathophysiology of human diseases. Front Chem. 2023 May 10;11:1158198. doi: 10.3389/fchem.2023.1158198. PMID: 37234200; PMCID: PMC10206224. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10206224/
Benzie IF, Choi SW. Antioxidants in food: content, measurement, significance, action, cautions, caveats, and research needs. Adv Food Nutr Res. 2014;71:1-53. doi: 10.1016/B978-0-12-800270-4.00001-8. PMID: 24484938. Available at: https://pubmed.ncbi.nlm.nih.gov/24484938/
Annisbuntewelt: Radicals and Antioxidants, Instagram, post from 07/2024. Available at: https://www.instagram.com/p/C85DZneNtm7/?igsh=cWpmd3UzM2tqbzZq
