In the rush by dermatologists and sunscreen companies to demonize sunlight exposure as the universal cause of skin cancers, there has been a total disregard for another factor that strongly protects against or strongly promotes skin damage. That factor is what we eat. Nutrition, according to whether it is healthful or noxious, can have either profoundly positive or negative influences on the skin.
As an example, polyphenols are antioxidant phytochemicals that prevent free-radical damage and thus protect the skin. Polyphenols are prevalent in foods such as nuts, seeds, onions, green tea, pomegranates, apples, berries, cherries and other fruits, grape seeds, as well as vegetables and dried legumes. They also exist in such nutrients as resveratrol and silymarin (milk thistle extract). These nutritional superstars are able to reduce inflammation, quench oxidative stress and thereby prevent free-radical damage to DNA, inhibit immunosuppression, and diminish dysregulation of cellular signaling pathways, thereby reducing the potential for skin cancers.[i],[ii]
Particularly interesting is the fact that green tea extract and other polyphenol-containing products such as grape-seed proanthocyanadins, have been shown to inhibit the formation of skin tumors. Two researchers, writing in the Archives of Dermatological Research, made the following conclusion after a thorough review of literature regarding polyphenols and skin cancer: “Based on the epidemiological evidence and laboratory studies conducted using in vitro and in vivo systems, it is suggested that routine consumption or topical treatment of these polyphenols may provide efficient protection against the harmful effects of solar ultraviolet radiation in humans.”ii
We might conclude that protective nutrition would include the consumption of several glasses of green tea daily, some dark green vegetables such as broccoli, spinach and other deep greens, and the daily habit of eating dark berries, cherries and other such fruits. But there are other vegetables involved in the fight against skin cancer.
Some of the best skin protectants are tomatoes, which contain the antioxidant lycopene. One investigation showed that among individuals who consumed forty grams of tomato paste daily for ten weeks, sunburn-resistance time increased by 40%,[iii] and other research demonstrated that eating other tomato-based products correlated to significantly reduced risk of sunburn after exposure to ultraviolet radiation.[iv] And it is also known that individuals with the lowest intake of alpha-carotene, beta-carotene, cryptoxanthin, lutein, and lycopene (all carotenoid antioxidants found in such vegetables as carrots and tomatoes) had a 50% increased risk for melanoma.[v]
And what are factors that have negative influences on the risk of skin cancer? Alcohol consumption is one such factor; research indicated a 250% increased melanoma risk among those who consumed two or more alcoholic drinks per day.[vi] There are at least two other negative dietary aspects that correlate to increased skin-cancer risk: first, the highest dairy-product consumption has also been shown to correlate to a 2 ½ times increase in risk of developing a squamous-cell carcinoma (common skin cancer, not melanoma).[vii] Secondly, the types of fats we consume are exceptionally important. In my book, I have discussed and documented this topic thoroughly, but suffice it to say that the types of fats we consume in junk foods are deadly, both for overall health and for skin cancer. They are filled with free-radical molecules that wreak havoc on the skin; if we eat such fats without massive quantities of colorful fruits and veggies, we will be much more susceptible to skin damage and potential cancer.
To summarize: to the extent that sunlight causes skin damage, it does so due to lack of proper nutrients in the diet, and there is little doubt that there will be some damage caused by sun exposure without proper nutrition. Even vitamin D, which protects against so many cancers (including skin cancer), will not be able to completely overcome the deleterious effect of the “suicide diet” that most of us consume.
[i] Afaq F, Katiyar SK. Polyphenols: Skin Photoprotection and Inhibition of Photocarcinogenesis. Mini Rev Med Chem 2011 Oct 28. [Epub ahead of print]
[ii] Afaq F, Katiyar SK. Skin photoprotection by natural polyphenols: Anti-inflammatory, anti-oxidant and DNA repair mechanisms. Arch Dermatol Res 2010;302:71.
[iii] Stahl, W. et al. Dietary Tomato Paste Protects against Ultraviolet Light–Induced Erythema in Humans. J Nutr 2001;131:1449-51.
[iv] Aust, O. et al. Supplementation with tomato-based products increases lycopene, phytofluene, and phytoene levels in human serum and protects against UV-light-induced erythema. Int J Vitam Nutr Res 2005;75:54-60.
[v] Millen A. et al. Diet and melanoma in a case-control study. Cancer Epidemiol Biomarkers Prev 2004;13:1042-51
[vi] Bain, C. et al. Diet and melanoma. An exploratory case-control study. Ann Epidemiol 1993;3:235-38.
[vii] Hughes, M. et al. Food intake and risk of squamous cell carcinoma of the skin in a community: The Nambour skin cancer cohort study. Int J Cancer 2006; online publication ahead of print.