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The Role of Nutrition in Skin Cancer
By Heather Davis, MS, RDN, LDN
As the weather warms, the days lengthen, and the UV index increases, we are reminded to reach for our sunscreen or protective clothing when spending a day outdoors. Most of the messaging we hear about skin cancer prevention tells us that focusing on these physical barriers is the best way to prevent skin cancer. Research shared by the Skin Cancer Foundation suggests that regular daily use of SPF 15 sunscreen, when used as directed, can reduce the risk of developing squamous cell carcinoma by about 40% and lower melanoma risk by 50%.1 However, nutrition may also have a part to play.
Nonmelanoma skin cancer (NMSC) is the most common cancer among Americans. NMSC tumorigenesis is a process unfolding over time, and damage from free radicals plays a role in the initiation of this process. The harmful effects of UV-induced oxidative stress at the level of the skin occur through multiple mechanisms that involve alterations to proteins and lipids, promotion of inflammation, immunosuppression, DNA damage, and activation of signaling pathways that affect gene transcription, proliferation, and apoptosis. Where DNA damage is concerned, reactive oxygen species (ROS) can oxidize DNA bases, particularly guanine, leading to the formation of lesions such as 8-oxo-deoxyguanine, which researchers classify as highly mutagenic. In addition, ROS-driven changes to lipids and proteins lead to abnormal cellular signaling, potentially promoting carcinogenesis. Oxidative stress can also lead to the synthesis and release of matrix metalloproteinases that degrade collagen and accelerate skin aging.2
With all this in mind, it’s not hard to see how supporting the body’s antioxidant defenses may help maintain healthy skin and reduce skin cancer risk, even in the presence of UV radiation.
Sunscreen Concerns
Even though sunscreen can be a powerful force for skin cancer prevention, there are concerns about the potential negative health effects of certain ingredients commonly found in these products. Many traditional sunscreens may contain chemical components that have endocrine-disrupting activity or can be carcinogenic, neurotoxic, bioaccumulative, allergenic, or toxic for human reproduction.3 The Endocrine Society and the World Health Organization define an endocrine-disrupting chemical (EDC) as “an exogenous substance or mixture that alters function(s) of the endocrine system and consequently causes adverse health effects in an intact organism, or its progeny, or (sub)populations.”3 An increased risk for reproductive harm, obesity, and cancer are among the concerns expressed by experts. In some cases, a heightened risk for hormone-dependent cancers such as breast, endometrium, prostate, testis, and thyroid may be present with chronic exposures.3
The UV filters (UVFs) contained in some sunscreens may even harm the skin directly. Exposure to sunlight may cause these compounds to degrade, promoting ROS and oxidative stress in skin cells. Given this, how do experts define a “safe” sunscreen?
Authors from a 2023 published review in Applied Sciences say to meet this mark, sunscreens “must not be absorbed through the skin or if they [are], only in the stratum corneum, must not act as an EDC, must not favor the absorption of other chemical substances, must be photostable, must not cause allergies or photosensitivity, must not be bioaccumulative, and must be easily degradable and not effect flora and fauna.”3
UVFs can be of a physical or chemical nature. Chemical UVFs absorb UV rays and convert them to thermal energy; physical UVFs reflect UV rays. Certain chemical UVFs, such as benzophenone, dibenzoylmethane, and cinnamate derivatives, may pose some of the highest risks. Inorganic UVFs such as zinc oxide and titanium dioxide, which show poor absorption across the skin, appear to be safer than organic UVFs such as oxybenzone and octinoxate, which are much more readily absorbed.3 However, some studies have raised concerns that emerging nanoparticle technology meant to better disperse zinc oxide and titanium dioxide residue in the cream may have some unintended consequences potentially raising toxicity risk in these compounds.4
Plant-Based UVFs in Sunscreen
With evidence showing strong in vitro antioxidant action of many plant-based bioactive compounds paired with knowledge of their poor in vivo bioavailability, sunscreen manufacturers are seeking more ways to bypass the use of harmful chemicals described above in favor of topical forms of phytochemical ingredients. Poor solubility of topical preparations has been a concern in the past with phytochemicals; however, new nano-formulations such as nanostructured lipid carriers, liposomes, and nano-emulsions, might be a solution to optimizing delivery in skin. In animal models, topical administration of tea polyphenols and resveratrol showed protection against UVB-induced carcinogenesis and inflammation, though more human clinical trials are needed to confirm these effects.2 Resveratrol may exert its topical effect in part through increasing the production of endogenous antioxidants in the skin such as catalase and superoxide dismutase.
Nature’s Internal Sunscreen
Some human clinical studies have examined the potential role of antioxidant supplements such as vitamin C, E, carotenoids, and selenium on NMSC risk, with conflicting results. Methodology in these cases may be suspect, since research also supports the idea that antioxidants in the form of isolated supplements may function in a different manner than that provided in the whole food form, and the former may even carry a higher risk for prooxidation compared with the latter. Therefore, it’s important that better quality studies that can consider these factors are conducted.5
As is common in most areas of nutrition research, designing a study to evaluate the effects of antioxidant intake via whole foods is challenging. However, in the limited human clinical trials exploring this topic, dietary patterns such as the Mediterranean diet that were associated with adequate fiber, higher intake of fruits, vegetables, and whole grains, and rich in food-based beta carotene and vitamin C showed promise.5 It’s worth noting that the same body of research concludes that while antioxidant-rich whole foods are encouraged, antioxidant supplements are not recommended for skin cancer prevention.5
Much of life on Earth has evolved mechanisms to counteract the effects of UV radiation. Skin developed many photo-adaptive mechanisms, including the production of endogenous antioxidants, like melatonin, and UV-absorbing metabolites. Vitamin D and its metabolites may also improve keratinocyte survival after UVB irradiation, enhancing DNA repair.2 Melatonin, synthesized from serotonin with the help of nutrient precursors and cofactors, including tryptophan, vitamin B6, vitamin D, and omega-3 fatty acids, EPA and DHA, helps protect skin from UV radiation. Some of the metabolites of melatonin, such as 4-hydroxymelatonin, may have an even stronger antioxidant effect than melatonin itself.2
A wide variety of isolated phytonutrient-containing plant-based compounds—such as resveratrol, lycopene, isothiociantes, green tea polyphenols, curcumin, and rosmarinic acid—have been investigated as possible chemopreventive agents in melanoma. As described earlier, many of these compounds have promising in vitro data demonstrating their potential, and some have been investigated in larger epidemiologic studies; however, clinical data in humans is lacking, and many questions about in vivo bioavailability persist.6
Emphasis on ‘Diet as a Whole’
When attempting to make sense of the mixed findings concerning antioxidants and cancer, there’s a growing body of research emphasizing the importance of avoiding isolated antioxidant compounds in supplement form in favor of focusing on a bigger-picture whole diet approach. Those in support of this method point to well-established examples of similar cases in nutrition science, such as interventions for hypertension.5 Research in hypertension had very limited success using isolated dietary supplementation but had great success with interventions using whole foods and whole-diet approaches.5 Multiple nutrients and phytochemicals have synergistic effects, and their sum—found in diverse whole foods—may be greater than the parts. Dose-response effects are also present and may dictate a great deal about the pro- or antioxidant nature of a supposed antioxidant compound. Taken together, experts say there’s reason to believe we may have better luck answering the many questions about nutrition and skin cancer with a whole diet approach. Supporting the body’s endogenous antioxidants, like melatonin, through ensuring broad nutrient adequacy of nutrient precursors and cofactors, along with meeting nutrient needs through a nutrient-dense and diverse diet, can aid the fight against skin cancer.
— Heather Davis, MS, RDN, LDN, is editor of Today’s Dietitian.
References
1. All about sunscreen. Skin Cancer Foundation website. https://www.skincancer.org/skin-cancer-prevention/sun-protection/sunscreen/. Updated April 2025. Accessed April 5, 2025.
2. Dunaway S, Odin R, Zhou L, Ji L, Zhang Y, Kadekaro AL. Natural antioxidants: multiple mechanisms to protect skin from solar radiation. Front Pharmacol. 2018;9:392.
3. Santander Ballestín S, Luesma Bartolomé MJ. Toxicity of different chemical components in sun cream filters and their impact on human health: a review. Applied Sciences. 2023;13(2):712.
4. Smijs TG, Pavel S. Titanium dioxide and zinc oxide nanoparticles in sunscreens: focus on their safety and effectiveness. Nanotechnol Sci Appl. 2011;4:95-112.
5. Katta R, Brown DN. Diet and skin cancer: the potential role of dietary antioxidants in nonmelanoma skin cancer prevention. J Skin Cancer. 2015;2015:893149.
6. DeWane ME, Shahriari N, Grant-Kels JM. Nutrition and melanoma prevention. Clin Dermatol. 2022;40(2):186-192.