How Sea Kelp Defends Herself Against UV Damage

While just an ordinary star amongst the others in the Milky Way, the sun is our lifeline to life on Earth, without it we would just be another cosmic popsicle. The energy radiating from the sun and through space keeps us warm and provides food. Animals have evolved to depend on solar powered plant and plant-like producers for nutrition, shelter, and oxygen. Yet, the energy from the sun can also be hostile and deadly. Not only can extreme heat dismantle our survival adaptations, the intense UV spectrum can wreck havoc inside our cells. Most life on earth has developed unique mechanisms to harness and mitigate the suns powerful energy; humans and sea kelp are no exceptions. Let us take a dive in and see how humans can harness sea kelp’s adaptations to protect itself from the sun.  



Humans are not the only animals that are susceptible of sunburns. All plants and  animals have the potential for a sunburn. Lions, tigers, and bears, oh.. well.. have fur that protects them from the burning rays of the sun. Fun fact, even though giraffes have fur, their tongues can get a tan. They have large amounts of melanin producing cells in their tongues to protect against sunburn. But what about non-furry animals? How have they evolved to battle UV rays?


Hippopotamuses spend much of their life in the scorching sun, and did not evolve fur. Their behavioral adaptations for sun protection is to stay in the water or to cover themselves in mud and dirt for a physical sunblock. However much more interestingly, hippos secret a red oily substance from their skin, called hipposudoric acid, or ‘blood sweat’ (Mitchell). For many years observers didn’t understand the function of this secretion. It was only in recent history that scientists figured out that the ‘blood sweat’ has immense UV protection capabilities. This makes so much more sense, because is often secreted on the hottest days or while the hippo is traveling from one water hole to the next. What a convenient adaptation, self produced sunscreen.


It is one thing to have fur or cover up to seek shelter to sheild oneself from the suns rays. But what if you can’t do either? Most fish produce a chemical called gadusol, which safely absorbs the suns UV rays (Rood). However, mammals did not evolve this excellent enzymatic ability of gadusol producing cells,most mammals evolved to produce melanin, a compound that shields the sun from the surrounding cells. Even dolphins produce melanin which visually makes their blue ‘tan’ darker, it also blocks the sun from the underlying skin cells. Along with

Take a look at the geography of our ancient ancestors, and you can
see how humans have adapted to the sun. Many thousands of years passed while groups of humans traditionally stayed in a general climate. Thus allowing for evolutionary patterns to take place within entire populations. The relationship of these adaptations in relation to the sun is quite interesting. The early humans who lived in tropical or desert environments favored the adaptations of less body hair, more sweat glads, and more melanin producing cells (Modern Human). These adaptations allowed them to stay cooler, and also protect their skin from intense UV rays. 


The balance between the need for the suns UV rays and prevention from too much is quite delicate. If the skin absorbs too much sun, its’ go-to defense is to use folic acid to neutralize the free radicals bouncing around the cell that are causing cellular destruction. Folic acid is also essential for fetal development. Therefore, only the persons near the equator that had sufficient folic acid were the ones that were able to reproduce (Modern Human), and therefore favoring the survival of humans with darker skin in the equatorial regions. 

On the flip side of UV rays, when they are good, is when absorbed by the skin this helps the body use vitamin D, which is needed to absorb calcium, an essential element for bone health and cardiac rhythm (Modern Human) among other uses for calcium in the body. This need for UV rays to penetrate the skin is one possible explanation why humans living in geographic zones with less sunlight developed lighter skin to allow for maximum UV absorption. Even though these populations suffer high amounts of skin cancer, this didn’t seem to affect the adaption of lighter skin. Unlike populations at the equator whose sun defense adaptations were essential for species survival, skin cancer tends to effect people after their child bearing years, and thus doesn’t play an important role in genetic adaptations (Modern Human). 

Fast-forward to the modern human, we now can criss cross the globe in single day and can generally choose to live in any climate. Many of our species is not equipped to handle the intense UV rays given the current environments we prefer to reside. Like me. I have fair skin, blue eyes, and light hair. I grew up in the Southern California desert, and my skin paid the price! Not only am I covered in freckles, I have visible signs of sun damage, and I also suffer from multiple forms of skin cancer. Even though I often used sunscreen as a child, it wasn’t enough to protect my ill-adapted skin from the rays of the California sun. Science and history has shown us the harmful effects of UV radiation on human skin, and impressed upon us the need for defense. No matter how much melanin your body naturally makes, everyone is susceptible to UV damage with enough exposure. 

 Of course, where humans lack in natural adaptations, we make up for it with our big beautiful brains. Our creative species have been harnessing the power of plants to deal with the suns rays for quite some time. Several Native American tribes in the Pacific Northwest used tsuga candensis, a type of pine needle salve to help heal sunburns, while others in the American Southwest harnessed the plant powers of aloe barbadensis miller for pain relief and quick repair (Aldahan, 2015). The world wide documentation of cultures using plants for sun protection and for their healing properties is quite extensive and impressive. After all, plants cannot escape the sun, they cannot move their roots into the shade, or seek shelter. Plants have to engineer themselves to survive where ever they put their roots down. 


True, plants use photosynthesis to make chlorophyll from some of the UV energy, but that is only small portion of the total energy they absorb. Excess light and energy must be dissipated from the plants to avoid UV damage, just like humans. Plants have developed all sorts of methods to deal with excessive UV rays. Most importantly to humans, they manufacture a plethora of compounds to chemically neutralize too much radiation. We are in a time of scientific understanding to harness these compounds much more reliably and predictable than our ancestors before us. I believe we can create plant based sunscreens that work better and are safer than what we have come to accept today.  

Early synthetic sunscreens were developed in the 1920s, and their use today is widely established and encouraged. It is also known that the manufacturing process of the chemicals that are in our sunscreens is environmentally unfriendly and over the past 50 years, the devastation they are causing for marine life is heartbreaking. I believe these synthetic sunscreens are causing more harm than good in both humans and the environment. I am a huge proponent of using natural ingredients. There are several mineral based sunscreens on the market that are better for our skin and for the planet. Looking for plant based alternatives is an even better idea. As usual, I always turn to the power of plants, and more recently, I have turned towards the power of plant-like organisms in search for better sun protection. 


Sea Kelp is a master when it comes to dealing with the sun. True, sea kelp is not a plant, it is ‘plant-like’. Sea kelp and other algae are in the kingdom of protists, which are marine species that use photosynthesis to survive. It turns out, sea kelp is powerhouse of a factory for manufacturing biologically active compounds. This means that many of the compounds seaweed makes for itself, when applied to humans makes our cells behave a different way (Pal). When it comes to sun defense, the Mycosporine-like amino acids [MAA’s] that sea kelp makes are magical. Marine algae use MAA’s to convert the energy harmful radiation into heat energy and expel it into the water around it. They absorb the UV rays with more efficiency and at a greater spectrum than current sunscreens on the market (Rosic). They basically take the photon of energy and pass it along like the hot potato game right out back into the environment. There are a few companies that are developing sunscreens using these compounds. MAA’s could hold the future for impressive sunscreens. 


While we wait for better technology to harness the potential power of MAAs, sea kelp has more tricks to help humans cope with UV radiation. 


Brown and red sea kelps manufacture phlorotannins in high concentrations. They can consist up to 10% of the dry weight of the kelp! (Venkatesan). It turns out that phlorotannins are quite active little molecules, they are known to be antioxidant, anti-cancer, UV-regulators, and they have one more very interesting effect in human skin. They can down regulate (turn down) the enzymatic activity of tyronisase. This is the critical step in human skin that is in charge of turning on the melanin making machines in our skin. The melanogensis pathway is responsible for all our pigments: hair, eyes, and skin (Varghese).  If the pathway is turned down, this would decrease the amount of melanin being produced, and best of all, this can be applied topically and targeted (Manandhar). The potential cosmetic applications for reducing hyper-pigmentation are high, as well as a possibility to be incorporated into sunscreens to absorb the UV radiation, and scavenge for free radicles (Varghese). 


While chronological aging is just a fact of nature, photo aging doesn’t have to be. The effects of photo aging are quite different than those of chronological aging, and what do you know, sea kelp has a lot to offer.  As the last highlight for sea kelp, I would like to highlight the large volume of stable vitamins these majestic plant-like creatures make. Sea Kelp is known to have vitamins, A,B,C,D, and E! We’ve all heard that we need to eat our vitamins, but did you know they are good on the outside of skin too? 



First off, Vitamin A, aka retinol. While retinol can be irritating to the skin, it is much more tolerable if it is administered in nano-particles. New technologies have allowed for synthetic nano-particle of Retinol to be made. Vitamin A is highly effective at reversing photo aging ( Mukherjee). Do you know what else makes retinol in nano-particles? Yup, sea kelp. Just go straight to the source for some plant-like power and skip the laboratory chemicals.  

Second, Vitamin B. This wonderful vitamin has a profound effect on skin cell proliferation, specifically keratinocytes and fibroblasts (Rembe). Keratinocytes are the skin cells on our outer most surface of the skin that absorb the bulk of environmental stressors. By helping them proliferate, or reproduce faster, we can have healthier younger looking skin. 

Third, Vitamin C. If your into skin care and you are reading this far down into the blog, you probably already know how wonderful Vitamin C is for the skin. There are a multitude of studies out there they have proven the effects of topical Vitamin C. But, do you really know how?  Along with being a powerful antioxidant, Vitamin C. also promotes new collagen formation. (Telang). She does this by increasing the rate of of lipid peroxidation, and the product of this process, malondialdehyde, in turn stimulates collagen gene expression (Telang). Additionally, Vitamin C serves as a co-factor for the enzymes prolysyl and lysyl hydroxylase, the enzymes that are responsible for stabilizing and cross-linking the collagen molecules (Telang). Also, as we age, the amount of Vitamin C that can get from the inside to the outside of our skin drastically decreases. Therefore topical application is the preferred method for dermatologists (Telang). So now you know, some more little fun facts about Vitamin C. 

Fourth, Vitamin D. Well, we all know it is in our milk, the dairy industry has spent billions of dollars over many decades to drill that one into us. The bigger question, is Vitamin D useful topically? Well, yes, it turns out it does. Topical Vitamin D is a key player in combating photo damage. Vitamin D3 is the stuff we eat and is healthy for our bones. But Vitamin D2 is fantastic for our skin, and what do you know? It is also found in Sea Kelp. Best of all, Vitamin D2 is an excellent absorber of UVB radiation, which scientists blame on the ‘cancer-causing’ wave length (Wacker). 

Finally, Vitamin E. This another popular skin care ingredient, in fact it has been used for more than 50 years in dermatology. It is one of the most potent free radical scavengers around, which by the way is the number one cause of photo-aging (Keen). The challenge with Vitamin E, is keeping it stable in the bottle while waiting for it to be unleashed on our skin cells. Naturally occurring forms of Vitamin E are often the most stable and therefore the most potent in skin care formulas (Keen). 

Sea Kelp likes to keep high hold of her secrets. One cannot harness the power of her molecules by contact alone. You can’t just jump into a pile of sea weed and emerge ten years younger. Nope, she needs to be caressed a bit to let go of her magic. Through lacto-fermintation, Sea Kelp is transformed into a wonderful slimy nutrient filled goop! Next time you see that wonderful seeweed in the store, at the restaurant, or in your cosmetic products, go ahead and enjoy with a big smile, for you now know the powers that lay within. 





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Modern Human Diversity - Skin Color. Smithsonian, National Museum of Natural History. June 17th, 2020.


Mitchell, Chaffin. How Animals like Hippos, Elephants, and Whales Protect Themselves From the Sun. viewed July 2nd, 2021.


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Telang P. S. (2013). Vitamin C in dermatology. Indian dermatology online journal, 4(2), 143–146.


Varghese, P. K., Abu-Asab, M., Dimitriadis, E. K., Dolinska, M. B., Morcos, G. P., & Sergeev, Y. V. (2021). Tyrosinase Nanoparticles: Understanding the Melanogenesis Pathway by Isolating the Products of Tyrosinase Enzymatic Reaction. International journal of molecular sciences, 22(2), 734.


Venkatesan, J., Keekan, K. K., Anil, S., Bhatnagar, I., & Kim, S. K. (2019). Phlorotannins. Encyclopedia of Food Chemistry, 515–527.


Wacker, M., & Holick, M. F. (2013). Sunlight and Vitamin D: A global perspective for health. Dermato-endocrinology, 5(1), 51–108. BACK TO NEWS AND UPDATES


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