This summer, protect your skin with carotenoids so you can have your fun in the sun!
Humans have a sort of love-hate relationship with the sun. Who doesn't love to be outside on a sunny day, soaking up the warm rays? Not to mention it's those UVB rays that produce vitamin D in our skin. What we don't love so much are the wrinkles, sun spots, and potential cancer that come with excess UV exposure. The good news is that a group of antioxidants called carotenoids can protect your cells from UV-induced damage, potentially halting much of sun's negative effects.
Too much UV exposure generates harmful free radicals in the skin and cumulative exposure to these free radicals contributes to the break down of DNA, proteins – including collagen and elastin – and fats in skin cells. The consequence is that skin cells are damaged and cannot create healthy new cells, leading to wrinkles, sun spots, thin, and sagging skin. Excessive UV exposure also increases the risk of three different types of skin cancer – squamous cell carcinoma, basal cell carcinoma, and melanoma.
All of this may send you running for cover from the sun, but a growing body of research is showing that the class of plant nutrients called carotenoids has photoprotective properties, meaning they protect our cells from the damaging effects of UV radiation.
Carotenoids are a group of naturally-occurring plant pigments that are responsible for the red, yellow, and orange hues of fruits and vegetables like mangos, sweet potatoes, and tomatoes, and certain animals like shrimp, lobster, and salmon. They are also found in many dark green vegetables like spinach and kale but are masked by the large amounts of chlorophyll in these plants. There are more than 600 different carotenoids, although the most researched in relation to human health are beta-carotene, lycopene, lutein, zeaxanthin, and astaxanthin. These phytonutrients are known to be potent antioxidants that protect the body from cellular damage caused by free radicals, including those produced by UV radiation.
In addition to their antioxidant activity, the carotenoids also support immune and reproductive health and promote proper cellular communication and cell growth. Two carotenoids in particular are especially important for eye health – lutein and zeaxanthin are found in high concentrations in the macula, where they absorb blue light. By preventing a substantial amount of the blue light entering the eye from reaching the underlying structures involved in vision, lutein and zeaxanthin may protect against light-induced oxidative damage, which is thought to play a role in the development of age-related macular degeneration (AMD). Epidemiological studies provide some evidence that higher intakes of lutein and zeaxanthin are associated with lower risk of age-related macular degeneration.[i]
When it comes to protecting your skin, the carotenoids' antioxidant power really shines. You see, when your skin is exposed to sunlight, free radicals are formed. These free radicals are believed to be largely responsible for skin aging – breaking down DNA, proteins and fats in skin cells; this is often referred to as photo-oxidative damage and it is the process that can ultimately lead to skin cancer. Interestingly, one of carotenoids' main functions in plants is to protect the chlorophyll from photodamage[ii] and research is proving that carotenoids do the same for human cells.
Astaxanthin seems to be particularly effective at protecting skin against photodamage. A recent study found that astaxanthin “exhibited a pronounced photoprotective effect” on human skin cells exposed to moderate UVA radiation. The astaxanthin prevented cell death, reduced levels of reactive oxygen species (ROS) and other damaging free radicals, and protected cell membranes. The cells were treated with astaxanthin 24 hours before exposure to the UVA radiation.[iii] Lutein has also shown promise in protecting skin from photodamage. An animal study found that a diet rich in lutein (fed for two weeks before exposure) efficiently reduced UVB-induced cell proliferation and cell death.[iv] Another human clinical trial showed that 10 mg of lutein daily (along with its partner zeaxanthin) increased skin hydration, elasticity, and skin lipid content, while reducing oxidation of those beneficial lipids by 55 percent.[v]
Lycopene, maybe better known for promoting prostate health, has also been shown to exert photoprotective benefits, reducing inflammatory responses, maintaining normal cell proliferation, and possibly preventing DNA damage following UVB exposure.[vi]
And if you're looking for a healthy glow, forget about tanning, just eat lots of fruits and vegetables. A study released earlier this year suggests that eating a diet rich in foods containing carotenoids gives the skin a healthier glow than the sun.[vii] The study, from The University of Nottingham, found that people who eat more portions of fruit and vegetables each day have a healthier skin color, thanks to the carotenoids in the fruit and vegetables. While this study focused on Caucasian faces, the paper also describes a study that suggests the effect may exist cross culturally.
As the study above suggests, carotenoids are deposited in the skin and that's where they begin to really offer protection. It is thought that carotenoids protect against UV damage by their ability to act as antioxidants, as well as through their anti-inflammatory and immuno-modulating properties[viii] and their ability to decrease DNA damage and stimulate DNA repair processes.[ix]
It seems that amounts between 10 and 20 mg – the amounts typically used in studies – are sufficient to increase concentrations of these carotenoids in the skin to support skin health. It is important to note that it takes at least 8 to 10 weeks of supplementing with these amounts to sufficiently protect your skin.
Foods and Supplements
Carotenoids are fat-soluble nutrients and therefore require fat for absorption. Since most of the carotenoids in the diet come from plants, eating them with some healthy fats will enhance absorption.
Lutein and Zeaxanthin: These two yellow carotenoids are found together, with lutein predominating. Ironically, the foods with the highest amount of lutein and zeaxanthin aren't yellow at all, but green. Kale, spinach, Swiss chard, and collard greens all contain high amounts of these carotenoids. (As mentioned before, the lutein content is hidden by the high amounts of chlorophyll in these leafy greens.) The yolks of eggs can also be a good source of lutein and zeaxanthin, provided the chickens are fed a feed that contains them. While eggs contain less per ounce, it is better absorbed then vegetarian sources. Lutein and zeaxanthin are often found together in dietary supplements. A common source for deriving these carotenoids for supplements is marigold flowers.
Lycopene: Lycopene is a bright red carotenoid. It is found in apricots, pink grapefruit, tomatoes, and watermelon. As a dietary supplement, lycopene is available in mixed carotenoid formulations or by itself. Most supplements containing lycopene are oil-based and are sold in soft-gels. One wide-selling category of lycopene supplements are tomato extracts.
Astaxanthin: Astaxanthin is produced by a particular type of micro algae and as the algae are eaten by marine animals like krill then shrimp and salmon, astaxanthin makes its way up the food chain.
It is a red-orange color that is found in highest amounts in krill, shrimp, crustaceans (like lobster and crab), and salmon. Wild sockeye salmon has the highest concentration, with a 3.5oz serving providing 4mg. Red peppers, carrots, and tomatoes contain smaller amounts of this carotenoid. Astaxanthin is also available as a supplement and is typically derived from algae or krill.
Yes, the rays of the sun can do a number on your skin – if you let it. But if you are well-prepared and build up your defenses internally with the sunny reds, yellows, and oranges of the carotenoids, you can have your day in the sun.
[ii]http://en.wikipedia.org/w/index.php?title=Template:Cite_doi/10.1126.2Fscience.1187113&action=edit&editintro=Template:Cite_doi/editintro2: Armstrong GA, Hearst JE (1996). “Carotenoids 2: Genetics and molecular biology of carotenoid pigment biosynthesis " Faseb J. 10 (2): 228–37. PMID 8641556
[iii]Camera E, Matrofrancesco A, Fabbri C, Daubrawa F, Picardo M, Sies H, Stahl W. Astaxanthin, Canthaxanthin and Beta-carotene Differently Affect UVA-induced Oxidative Damage and Expression of Oxidative Stress-responsive Enzymes. Exp Dermatol 2008 (Sep 18).
[iv] Gonzalez S, Wu A, Pathak MA, Sifakis M, and Goukassian DA. Oral
administration of lutein modulates cell proliferation induced by acute UV-B radiation
in the SHK-1 hairless mouse animal model (Abstract). The Society of Investigative
Dermatology, 63rd Annual Meeting, Los Angeles, CA., 2002.
[vii]University of Nottingham (2011, January 12). Eating vegetables gives skin a more healthy glow than the sun, study shows. ScienceDaily. Retrieved May 2, 2011, from http://www.sciencedaily.com /releases/2011/01/110111133224.htm
[viii]Dinkova-Kostova AT. Phytochemicals as protectors against ultraviolet radiation: versatility of effects and mechanisms. Planta Med. 2008 Oct;74(13):1548-59.
[ix]Pereira BK, et al. Protective effects of three extracts from Antarctic plants against ultraviolet radiation in several biological models. J Photochem Photobiol B. 2009 Aug 3;96(2):117-29.