Here are a bunch of studies about nutritional and dietary skin cancer prevention. These are all nutrients that have been proven to be effective for reducing skin cancer.
Green Tea Polyphenols
A Randomized Controlled Trial of Green Tea Beverages on the In Vivo Radical Scavenging Activity in Human Skin (2017)
Conclusion: To test the effects of green tea on reducing free radical formation in skin, 32 participants were randomized to consume 3 cups daily of either green tea or water for two weeks. Electron paramagnetic resonance spectroscopy was used to measure the free radical scavenging activity in the skin before and after. Those consuming green tea were found to have a 28% higher free radical scavenging capacity in their skin compared to the water group, proving green tea is effective for reducing oxidative stress in human skin which is very important for reducing skin cancer and photodamage.
Note: Technical article explaining the mechanisms through which green tea prevents skin cancer.
Note: Article providing a comprehensive overview of how orally-consumed green tea polyphenols prevent skin cancer by inhibiting UV-induced immunosuppression and the ability of green tea polyphenols to repair UV-induced DNA damage in skin cells.
Note: Technical article explaining how orally consuming green tea prevents skin cancer by speeding up post-UVB exposure DNA repair.
Inhibition of UVB-Induced Skin Tumor Development by Drinking Green Tea Polyphenols is Mediated Through DNA Repair and Subsequent Inhibition of Inflammation (2009)
Note: Technical article explaining how orally consuming green tea prevents skin cancer by speeding up post-UVB exposure DNA repair and inhibiting post-UVB exposure inflammation.
Tea Consumption and Basal Cell and Squamous Cell Skin Cancer: Results of a Case Control Study (2007)
Conclusion: Tea consumption rates were evaluated and compared for 770 people with basal cell carcinoma (BCC) skin cancer, 696 people with squamous cell carcinoma (SCC) skin cancer, and 715 controls with no skin cancer. After adjusting for age, sex, and sunburn history, researchers found that regular tea drinkers had a significantly lower incidence of SCC skin cancer, and there was an even lower risk among life-long tea drinkers and heavier tea drinkers. A less significant relationship was found between tea consumption and BCC skin cancer.
Orally Administered Green Tea Polyphenols Prevent Ultraviolet Radiation-Induced Skin Cancer in Mice Through Activation of Cytotoxic T Cells and Inhibition of Angiogenesis in Tumors (2005)
Conclusion: Two groups of hairless mice were UVB-irradiated daily for 10 days and then 3x per week for six months to intentionally initiate and promote skin cancer. One group was given plain water to drink during this time, the other group was given water infused with green tea polyphenols. The green tea group suffered 35% fewer tumors, 63% less tumor multiplicity, and 55% less tumor growth compared to the plain water group. They also experienced reduced expression of matrix metalloproteinases (MMPs), the enzymes that break down skin collagen. “Green tea polyphenols have potential for development as a complementary and alternative medicine to prevent UV-induced nonmelanoma and melanoma skin cancers.”
Anti-Proliferative and Proapoptotic Effects of (-)-Epigallocatechin-3-Gallate on Human Melanoma: Possible Implications for the Chemoprevention of Melanoma (2004)
Conclusion: This study found that epigallocatechin‐3‐gallate, the major antioxidant in green tea, kills melanoma cancer cells in vitro by inhibiting proliferation and inducing apoptosis. Researchers state that drinking 4-6 cups of green tea daily is necessary to receive these benefits.
Conclusion: 10 separate experiments were carried out in this study testing the effects of various oral and IP injection green tea preparations on UV-induced and chemically-induced skin cancer in hairless mice. In half of the studies, giving the mice green tea resulted in either complete regression of skin cancer tumor or 90+% inhibition of tumor growth compared to control mice. The other half of studies found green tea effective for inhibiting tumor growth by 46-89% compared to the control mice.
Inhibitory Effect of Green Tea in the Drinking Water on Tumorigenesis by Ultraviolet Light and 12-O-Tetradecanoylphorbol-13-acetate in the Skin of SKH-1 Mice (1992)
Conclusion: Hairless mice were irradiated with UVB to intentionally induce severe photodamage and photocarcinogenesis and given green tea in their drinking water during this time to test the effectiveness of green tea at different brew strengths for preventing and healing photodamage and skin cancer. Researchers found as the green tea brew strength increased, so did it’s protective effect against sunburn. The UVB-induced red skin lesions in the mice given green tea were smaller and lighter in color compared to the plain water control group and the mice given stronger green tea enjoyed much better photoprotective effects compared to mice given a weaker green tea. More amazingly, the mice exclusively given green tea as drinking water developed skin tumors 55-93% smaller than the control group (depending on the tea concentration) and suffered 55% fewer number of tumors. Both weak green tea and strong green tea were also found to be completely effective for totally preventing the formation of basal cell carcinoma (BCC) skin cancer in all mice groups.
Conclusion: Study compared the selenium levels of 143 non-melanoma skin cancer patients and 103 healthy controls. The skin cancer patients had “significantly lower” levels of selenium.
Conclusion: 485 Australian adults were evaluated for blood levels for antioxidants – carotenoids, vitamin E, and selenium. They were then divided into three groups – low antioxidant levels, moderate, and high – and monitored for 8 years for development of BCC or SCC skin cancer. A very strong association was found between selenium levels and skin cancer incidence. Those with the highest selenium levels suffered a 60% lower BCC and SCC skin cancer risk compared to those with the lowest selenium levels.
Effects of Dietary Selenium on UVB-Induced Skin Carcinogenesis and Epidermal Antioxidant Status (1994)
Conclusion: Skin tumors were UV-induced in three groups of hairless mice. To test the effect of selenium on skin cancer, the three groups of mice were either given a selenium-deficient diet, a low-selenium diet, or high-selenium diet. After the skin cancer inducement, the mice were no longer subjected to UV irradiation and researchers observed the tumor activity. The mice in the deficient and low-selenium groups continued to suffer tumor activity – the tumors increased. However, the high-selenium group enjoyed an arrest of tumor activity.
Conclusion: Study evaluated the selenium levels of 101 melanoma skin cancer patients and found that their selenium were “significantly lower” compared to a healthy control group, with patients in the later stages of melanoma having even lower levels. “Our results, showing for the first time that malignant melanoma is associated with low Se concentrations, are consistent with results of epidemiologic studies showing an inverse correlation between serum Se levels and certain cancers.”
Note: Comprehensive article explaining the mechanisms through which fish-source omega-3 and omega-6 fatty acids support skin repair and photoprotection by increasing ceramide production (the glue that holds your skin cells together), inhibiting expression of matrix metalloproteinases (UV-stimulated enzymes the break down skin collagen), reducing inflammation, increasing people’s minum erythemal dose (sunburning threshold), improving skin hydration, improving skin wound healing, and deterring skin cancer development.
Effects of High-Fat Diets Rich in Either Omega-3 or Omega-6 Fatty Acids on UVB-Induced Skin Carcinogenesis in SKH-1 Mice (2011)
Conclusion: Two groups of hairless mice were fed different quality high-fat diets to test for an association with skin cancer. One group was given a diet very rich in healthy, high-quality fish oil omega-3 fats the other group was given a high fat diet rich in unhealthy fats very high in omega-6’s (soybean oil, corn oil) to simulate the typical American’s fat intake. The mice were blasted with intense UVB light adequate to induce skin cancer, twice a week, for 10 months. The mice were then euthanized and their skin examined. By the end of the study, the unhealthy fat group had more than double the amount of skin tumors as the healthy fat group. The healthy fat group also demonstrated physically smaller tumors. “Our results indicate that omega-3 fatty acids in an HFFO [high-fat fish oil] diet have beneficial effects against UVB-induced skin carcinogenesis in mice and these effects may be associated with an inhibition on UVB-induced inflammatory response.”
Note: Article providing a technical overview of how oral and topical caffeine protects against UV-induced skin cancer development in hairless mice experiments by enhancing the removal of DNA-damaged cells, increasing cancer cell death (apoptosis), and inhibiting tumor formation.
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