Which Phytonutrients offer Protection against UV and Sunburn?

Protecting your skin from the damaging effects of UV radiation is crucial for maintaining healthy and youthful-looking skin. Sunburn not only causes immediate discomfort but can also lead to long-term skin damage, premature aging, and an increased risk of skin cancer.

The effect of exposure to intense optical radiation (ultraviolet > visible light > infrared) is to excite electrons in the tissue, resulting in heating or burns. Due to the low penetrability of optical radiation, the effects mainly affect surface tissues, i.e., the retina and skin [2,3].  While infrared radiation energy can be used in therapeutics due to its beneficial effects, especially on connective tissue reconstruction and vitamin D synthesis (eustress) by activating 7-dehydrocholesterol, the photochemical effects of ultraviolet (400 nm–1 nm, 10¹⁵–10¹⁷ Hz, UVR) are detrimental. Excessive, long-term exposure to UVR can cause eye diseases (cataracts, retinal degeneration), skin dysfunctions in the form of burns, photoaging, skin cancer, and even systemic effects in the form of a weakened immune system. It is not only UVR that is dangerous. It turns out that free radicals are formed in the skin after exposure to a wide range of wavelengths, from UVB (280 nm) through VIS (700 nm) to near-infrared (NIR), both in vivo and ex vivo [4,5]. Visible light has been shown to be responsible for about half of the total oxidative load on the skin [6]. High doses of infrared radiation also cause the formation of reactive singlet oxygen and hydroxyl radicals in human skin [7]. Photodamage to the skin results primarily from the occurrence of chronic inflammation, immunosuppression, and photocarcinogenesis. (Flieger 2024)

While sunscreen is an important tool for sun protection, there are natural options that can provide additional photoprotection. One such option is incorporating phytonutrients into your diet. Phytochemicals, which are naturally occurring compounds found in plants, offer a range of benefits for skin health, including protection against UV radiation and sunburn. These compounds act as natural photoprotective agents, helping to shield the skin from the harmful effects of the sun.

In this article, we will explore the various types of phytochemicals that offer protection against UV radiation and sunburn. From powerful polyphenols found in green tea and resveratrol to the antioxidant-rich carotenoids present in tomatoes and carrots, we’ll delve into the world of phytochemical photoprotection. We’ll also discuss how vitamins C and E, flavonoids, anthocyanins, and other beneficial compounds contribute to natural sunburn prevention.

Key Takeaways:

• Phytochemicals, found in plants, offer natural photoprotection against UV radiation and sunburn.
• Polyphenols, carotenoids, vitamins C and E, flavonoids, anthocyanins, and other compounds play a role in protecting the skin from the sun’s damaging effects.
• Phytochemicals provide photoprotection through antioxidant and anti-inflammatory effects, UV absorption, DNA repair modulation, and boosting the body’s own antioxidant systems.
• Incorporating phytochemicals into your diet through fruits, vegetables, and herbs, or using supplements and topical products can help maximize protection against UV damage.
• Combining different types of phytochemicals and adopting sun safety measures like wearing protective clothing, avoiding peak sun hours, and consistent sunscreen use can enhance the effectiveness of natural photoprotection.

Brief Background on Sunburn, UV Radiation, and Skin Damage

Sunburn, caused by excessive exposure to ultraviolet (UV) radiation, is a common skin condition characterized by red, inflamed, and painful skin. UV radiation is a powerful form of energy emitted by the sun, with three main types: UVA, UVB, and UVC. UVA rays penetrate deep into the skin and contribute to premature aging, while UVB rays primarily cause sunburn. UVC rays are mostly absorbed by the Earth’s atmosphere and do not reach the skin.

The harmful effects of UV radiation on the skin are well-documented. Overexposure to UV rays can lead to immediate sunburn as well as long-term skin damage. Sunburn damages the DNA in skin cells, disrupts the skin’s protective barrier, and activates inflammatory responses. Prolonged and repeated sunburns can accelerate skin aging, cause pigmentation disorders, and increase the risk of skin cancer.

It is essential to protect the skin from UV radiation to prevent sunburn and reduce the risk of long-term damage. By understanding the causes and effects of sunburn and UV radiation, we can take proactive measures to safeguard our skin and maintain its health.

UV Radiation and Cell Signaling

Sunburn and skin damage from UV radiation result from the activation of specific cellular signaling pathways involved in DNA damage response, cell cycle arrest, and oxidative stress. Key pathways activated by UV radiation exposure include:

• MAPK/JNK Pathway: This pathway detects DNA damage signals and triggers programmed cell death (apoptosis) of severely damaged skin cells.
• p53 Pathway: The p53 tumor suppressor protein is activated by UV radiation and regulates DNA repair mechanisms as well as inducing cell cycle arrest to allow time for repair.
• NF-κB Pathway: UV exposure generates reactive oxygen species that activate the NF-κB inflammatory pathway, leading to inflammation, erythema (redness) and swelling characteristic of sunburn.

In summary, UV radiation disturbs signaling involved in critical cellular processes like DNA damage response, cell cycle control, apoptosis, and inflammation. Activation of these pathways contributes significantly to the visible skin reactions and underlying cellular disruption that occurs in response to UV overexposure.

Phytochemicals – Nature’s Photoprotection

In the quest for natural photoprotection against the harmful effects of UV radiation and sunburn, phytochemicals have emerged as beneficial compounds found in plants. These compounds, including polyphenols, carotenoids, vitamins C and E, flavonoids, anthocyanins, and other beneficial compounds, offer a promising avenue for safeguarding skin health.

Polyphenols

Polyphenols, such as Curcumin, EGCG in green tea, and Resveratrol, are widely recognized for their potent antioxidant properties. Found in various fruits, vegetables, and herbs, these compounds help neutralize free radicals and combat oxidative stress caused by UV radiation, thereby supporting skin health.

Curcumin: Inhibits radiation-activated NF-κB signaling, reducing inflammation and associated oxidative damage. Also induces Nrf2 antioxidant pathway.

EGCG: May support radiation-triggered ATM/ATR DNA damage signaling, improving repair capacity and genomic stability.

Resveratrol: Activates SIRT1 longevity pathway that gets suppressed by radiation, enhancing DNA repair and mitochondrial function

Carotenoids

Carotenoids like lycopene, astaxanthin, and beta–carotene are vibrant pigments abundant in fruits and vegetables. These compounds possess inherent UV-absorbing properties, aiding in the prevention of UV-induced damage to the skin. In addition, carotenoids exhibit antioxidant qualities that help reduce oxidative stress.

Plant constituents such as carotenoids and flavonoids are involved in the light-protecting system in plants and contribute to the prevention of UV damage in humans. As micronutrients they are ingested with the diet and are distributed into light-exposed tissues where they provide systemic photoprotection. beta-Carotene is an endogenous photoprotector, and its efficacy to prevent UV-induced erythema formation has been demonstrated in intervention studies. Lycopene is the major carotenoid of the tomato and is a very efficient singlet oxygen quencher in the group of carotenoids. Following ingestion of lycopene or tomato-derived products rich in lycopene, photoprotective effects have been demonstrated. After 10-12 weeks of intervention a decrease in the sensitivity towards UV-induced erythema was observed in volunteers. Dietary carotenoids may contribute to life-long protection against harmful UV radiation. (Stahl 2005)

• Absorption of UV rays – The chemical structure of carotenoids allows them to absorb UV light, acting as a natural photoprotective filter to prevent UV penetration and initial DNA damage.
• Quenching reactive oxygen species (ROS) – Carotenoids can directly scavenge and neutralize ROS like singlet oxygen and peroxyl radicals generated by UV exposure, disrupting oxidative signaling cascades.
• Regulating apoptosis – Carotenoids may downregulate UV-induced caspase activation and apoptotic pathways that can cause skin cell death and blistering.
• Inhibiting inflammation – Carotenoids can block UV-triggered activation of inflammatory mediators like NF-kB and AP-1, reducing erythema, swelling and irritation.
• Boosting Nrf2 signaling – Some carotenoids can activate the Nrf2 antioxidant response pathway, enhancing endogenous enzymatic antioxidant defenses against acute UV damage.
• Supporting DNA repair – Through antioxidant effects, carotenoids can favorably modulate cellular signaling involved in DNA repair processes like nucleotide excision repair and base excision repair.

Carotenoids are pigments existing in a wide variety of vegetables and fruits, especially in tomatoes. They also appear in considerable amounts in human plasma and tissues. However, carotenoids are exclusively synthesized by plants. Hence those appearing in animals and humans have been acquired through the diet. Carotenoids decrease reactive oxygen species (ROS) in aerobic metabolism (29).

About 50 variants of carotenes are present in a typical human diet and, of these, six are found mainly in the blood: α-carotene, β-carotene, zeaxanthin, lutein, β-cryptoxanthin, and lycopene. Of these, lycopene is the most efficient regarding anti-oxidant activity (30). In vitro and in vivo studies have revealed that carotenoids can suppress UVA and UVB-mediated ROS formation, thereby, preventing photoinactivation of anti-oxidant enzymes, lipid peroxidation, and induction of DNA damage caused by oxidative stress (30, 31). (Parrado 2018)

So in summary, the photoprotective signaling effects of carotenoids stem from their ability to limit oxidative damage, suppress UV-induced inflammation and cell death, while activating endogenous antioxidant systems and DNA repair capacity. This comprehensive signaling modulation reduces molecular damage from UV radiation.

See here for foods high in carotenoids.

Vitamins C, D, and E

Vitamins C, D, and E are essential nutrients known for their skin-protective properties. Vitamin C, found in citrus fruits and leafy greens, acts as an antioxidant, fighting off harmful free radicals caused by UV exposure. Vitamin E, present in nuts, seeds, and vegetable oils, helps defend against UV-induced skin damage by reducing oxidative stress.

Recent research points to Vitamin D not only as as a possible protectant, but also as a treatment for sunburn!

the results of our in vivo human study, combined with animal and in vitro models, suggest that vitamin D₃ exerts immunomodulatory effects at the cellular and tissue level by selectively inducing the differentiation of anti-inflammatory, M2-macrophages. M2-macrophages, through the expression of arginase-1, downregulation of TNF-α and iNOS, and induction of autophagy, boost the resolution of inflammation, promote tissue repair, and enhance wound healing. Thus, vitamin D₃ may serve a unique role in the skin, acting as an “endocrine barrier” to provide additional protection against environmental injury and effectively maintain skin barrier function.

…pharmacological inhibition of autophagy increases apoptosis following acute UVR exposure, suppresses the recruitment of M2-macrophages into sunburned skin, and prevents the vitamin D₃-dependent downregulation of proinflammatory mediators (article under review). Taken together, these data support a critical role for M2-macrophages with enhanced autophagy in mediating the anti-inflammatory and protective effects of vitamin D₃ after sunburn. (Scott 2017)

A blinded, unsupervised hierarchical clustering of participants based on global gene expression profiles revealed that participants with significantly higher serum vitamin D₃ levels after treatment (p=0.007) demonstrated increased skin expression of the anti-inflammatory mediator arginase-1 (p=0.005), and a sustained reduction in skin redness (p=0.02), correlating with significant expression of genes related to skin barrier repair. In contrast, participants with lower serum vitamin D₃ levels had significant expression of pro-inflammatory genes. (Scott 2017a)

In summary Scott et al found that a high-dose vitamin D3 supplementation after sunburn can modulate inflammation by increasing arginase-1 expression and reducing pro-inflammatory mediators. This implicates arginase-1 induction as a potential mechanism for the anti-inflammatory effects of vitamin D in human skin.

Flavonoids

Flavonoids like quercetin and rutin are plant-derived compounds widely distributed in fruits, vegetables, and herbs. Known for their antioxidant and anti-inflammatory properties, flavonoids help mitigate the harmful effects of UV radiation and contribute to maintaining healthy skin.

Flavonoids like quercetin and rutin positively modulate cellular signaling to protect against UV damage:

• Antioxidant activity – Flavonoids directly scavenge reactive oxygen species generated by UV radiation, preventing activation of oxidative stress-responsive pathways like MAPK, NF-kB and apoptosis.
• Anti-inflammatory effects – They inhibit UV-induced inflammatory signaling molecules like COX-2, IL-6, IL-8, blocking inflammation, erythema and associated cellular damage.
• Regulating apoptosis – Quercetin inhibits UV-induced activation of caspases and signaling involved in cell death pathways, maintaining skin cell viability.
• Modulating cell survival pathways – Flavonoids enhance UV-suppressed PI3K/AKT signaling involved in cell growth/proliferation, promoting skin cell survival.
• Enhancing DNA repair – They appear to favorably alter p53, MAPK and other DNA damage response pathways to boost nucleotide excision repair capacity after UV exposure.
• Phase II enzyme induction – Flavonoids activate Nrf2 signaling which induces antioxidant enzymes like heme oxygenase-1 to establish UV photoprotection.

In summary, the signaling effects of flavonoids enhance natural antioxidant defenses, limit oxidative damage and inflammation, support cell viability, and promote efficient DNA repair in response to UV radiation. This helps maintain skin health.

Anthocyanins

Anthocyanins are vibrant pigments responsible for the rich colors of many fruits, vegetables, and flowers. These compounds possess potent antioxidant and anti-inflammatory properties, supporting skin health and providing natural photoprotection against UV radiation.

More specifically:

Other Beneficial Compounds

In addition to the well-known phytochemicals, other compounds like caffeic acid, sulforaphane, and melatonin have demonstrated photoprotective potential. These compounds, present in various plants and foods, contribute to the natural defense against UV radiation and provide additional skin benefits.

Mechanisms of Phytochemical Photoprotection

This section will delve into the mechanisms by which phytochemicals provide photoprotection to the skin. It will explain how these compounds act as antioxidants, helping to neutralize free radicals and reduce oxidative stress caused by UV radiation. It will also explore their anti-inflammatory effects, their ability to absorb UV radiation, their role in modulating DNA repair mechanisms, and their ability to boost the body’s own antioxidant systems.

Antioxidant Effects:

Phytochemicals exhibit powerful antioxidant effects, which play a crucial role in photoprotection. By scavenging and neutralizing free radicals, they help minimize oxidative stress induced by UV radiation. This antioxidant activity helps protect the skin from damage and reduces the risk of premature aging.

Anti-inflammatory Effects:

In addition to their antioxidant properties, phytochemicals also possess notable anti-inflammatory effects. UV radiation can trigger inflammatory responses in the skin, leading to redness, swelling, and discomfort. Phytochemicals help mitigate this inflammation, promoting a calmer and more balanced skin response.

UV Absorption:

Some phytochemicals have the ability to absorb UV radiation. By absorbing and dissipating these harmful rays, they prevent them from reaching the deeper layers of the skin, thereby reducing the risk of sunburn and UV-induced damage.

DNA Repair Modulation:

UV radiation can cause DNA damage, which increases the risk of skin cancer. Phytochemicals can modulate DNA repair mechanisms, aiding in the restoration of damaged DNA and reducing the likelihood of mutations and cellular abnormalities.

Boosting Endogenous Antioxidant Systems:

Phytochemicals also have the ability to boost the body’s endogenous antioxidant systems. They enhance the activity of enzymes involved in antioxidant defense, such as superoxide dismutase and glutathione peroxidase. This amplification of the body’s natural defense mechanisms further enhances photoprotection.

Getting Phytochemical Photoprotection

In order to maximize photoprotection against UV radiation and sunburn, it is important to incorporate phytochemicals into your daily routine. There are several different ways to obtain these beneficial compounds, including through dietary sources, supplements, and topical products.

Dietary Sources

Fruits, vegetables, and herbs are rich sources of phytochemicals that can provide natural photoprotection for your skin. Incorporating these foods into your diet is a great way to ensure you are getting a variety of phytochemicals. Some examples of phytochemical-rich foods include:

• Berries such as blueberries, strawberries, and raspberries
• Leafy green vegetables like broccoli, spinach, kale, and arugula
• Colorful fruits like oranges, watermelon, and papaya
• Herbs and spices such as turmeric, ginger, and garlic

By including these foods in your meals and snacks, you can increase your intake of phytochemicals and provide your skin with natural photoprotection.

Supplements

If it is difficult to obtain sufficient phytochemicals through your diet alone, supplements can be a convenient option. There are various supplements available that contain concentrated doses of specific phytochemicals, such as polyphenols, carotenoids, and vitamins C and E. These supplements can help to boost your photoprotection and support your skin health.

It is important to consult with a healthcare professional before starting any new supplement regimen, as they can provide guidance on the appropriate dosage and potential interactions with any medications you may be taking.

Topical Products

In addition to dietary sources and supplements, there are also topical products available that contain phytochemicals for direct application to the skin. These products, such as creams, serums, and oils, can enhance the photoprotective properties of your skincare routine.

Look for skincare products that contain key phytochemicals known for their photoprotective effects, such as green tea extract, resveratrol, and vitamin C. These ingredients can provide an extra layer of protection against UV radiation and help to maintain the health and appearance of your skin.

By incorporating phytochemicals through dietary sources, supplements, and topical products, you can enhance your photoprotection against UV radiation and sunburn, promoting optimal skin health.

Maximizing Protection Against UV Damage

In order to maximize protection against UV damage, it is important to consider various strategies and factors that can enhance the effectiveness of phytochemicals in photoprotection. By combining different types of phytochemicals and incorporating lifestyle measures, individuals can achieve a comprehensive approach to protect their skin from UV radiation.

Combining Phytochemicals – Synergies

Research suggests that combining different types of phytochemicals can lead to synergistic effects and enhance photoprotection. By incorporating a variety of phytochemical-rich foods in your diet, such as fruits, vegetables, and herbs, you can benefit from the diverse array of photoprotective compounds they contain. The synergistic interactions between these phytochemicals can provide amplified protection against UV damage.

Lifestyle Factors

In addition to incorporating phytochemicals into your diet, lifestyle factors play a crucial role in maximizing protection against UV damage. Wearing protective clothing, such as hats, long-sleeved shirts, and sunglasses, can provide an extra layer of defense against harmful UV rays. Avoiding peak sun hours, typically between 10 am and 4 pm when the sun’s UV radiation is strongest, can also minimize exposure. By being mindful of these lifestyle factors, you can further enhance your skin’s protection against UV damage.

Sunscreen Use

While phytochemicals offer natural photoprotection, it is important to remember that they cannot replace the effectiveness of sunscreen. Sunscreen should always be an integral part of your sun protection routine. Apply a broad-spectrum sunscreen with an SPF of 30 or higher, and reapply every two hours or after swimming or sweating. By combining sunscreen use with the incorporation of phytochemicals and lifestyle factors, you can create a comprehensive approach to maximize protection against UV damage.

Conclusion

Summary of key points

In conclusion, incorporating phytochemicals into your diet can provide natural photoprotection against UV radiation and sunburn. Throughout this article, we have explored the importance of protecting the skin from UV damage and the benefits of using natural compounds for photoprotection.

We discussed various types of phytochemicals, such as polyphenols, carotenoids, vitamins C and E, flavonoids, anthocyanins, and other beneficial compounds found in plants. These phytochemicals offer antioxidant and anti-inflammatory effects, UV absorption, DNA repair modulation, and can boost the body’s own antioxidant systems.

However, it is important to note that phytochemicals should not replace sun safety measures, such as wearing protective clothing, avoiding peak sun hours, and safe sunscreen use (Consider sunscreens based on zinc to block UV, rather than nano-titanium).

To achieve optimal skin health, it is recommended to incorporate phytochemical-rich foods into your diet, consider supplements when necessary, and use topical products that contain these beneficial compounds. Prioritizing sun safety measures alongside the use of phytochemicals will help maximize your protection against UV radiation and maintain healthy, radiant skin.

For more, see Natural Compounds as Radioprotective Agents.

FAQ

Which phytochemicals offer protection against UV and sunburn?

Phytochemicals such as polyphenols, carotenoids, vitamins C and E, flavonoids, anthocyanins, and other beneficial compounds found in plants offer natural photoprotection against UV radiation and sunburn.

What causes sunburn and how does UV radiation damage the skin?

Sunburn is caused by excessive exposure to UV radiation, which can lead to premature aging, sunburn, and an increased risk of skin cancer. UV radiation damages the skin by causing oxidative stress and inflammation, and by altering the DNA in skin cells.

What are some examples of phytochemicals that provide natural photoprotection?

Some examples of phytochemicals that provide natural photoprotection include polyphenols such as curcumin, green tea, and resveratrol; carotenoids such as lycopene, astaxanthin, and beta-carotene; vitamins C and E; flavonoids such as quercetin and rutin; anthocyanins; and other beneficial compounds like caffeic acid, sulforaphane, and melatonin.

How do phytochemicals provide photoprotection to the skin?

Phytochemicals act as antioxidants, reducing oxidative stress caused by UV radiation. They also have anti-inflammatory effects, absorb UV radiation, modulate DNA repair mechanisms, and boost the body’s own antioxidant systems.

How can I incorporate phytochemicals into my daily routine for photoprotection?

You can include phytochemicals in your diet by consuming fruits, vegetables, and herbs that are rich in these compounds. Additionally, there are supplements available that provide concentrated doses of phytochemicals, and topical products that contain phytochemicals for direct application to the skin.

How can I maximize protection against UV damage using phytochemicals?

You can maximize protection against UV damage by combining different types of phytochemicals, as they may have synergistic effects. Additionally, practicing lifestyle factors like wearing protective clothing and hats, avoiding peak sun hours, and consistently using sunscreen can further enhance photoprotection.

Source Links

• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9416108/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2813915/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10855854/