The sun is viewed by humans through a duality lens as both necessary for life, energy, and happiness, but also something that can be dangerous. We need our vitamin D and serotonin boost, but too much may promote skin cancer.
At some point in the evolutionary timeline, we lost a sun protective enzyme called photolyase and replaced it with a less efficient nucleotide excision repair mechanism for sun-induced DNA damage. Photolyases are found in plants, fungi, many animals, bacteria and even yeast, and are responsible for scanning DNA for signs of UV damage and quickly making repairs. For some reason, humans lost this enzyme along the way and it isn’t clear when or why.
It was first thought that humans evolved with different shades of skin color dependent on climate and latitude. However, this theory has changed. For a long time, scientists thought that light skin evolved roughly 40,000 years ago. A recent discovery and DNA analysis of a northern European hunter-gatherer from 7,000 years ago with dark skin and blue eyes spawned the theory that light skin is a much more recent evolutionary adaptation.
This research has led to the food production theory, that states that the dietary switch to grains could be the reason Europeans developed lighter skin, not the environment. The cereal-rich diet of Neolithic farmers lacked vitamin D so Europeans rapidly lost their dark skin pigmentation only once they switched to agriculture because it was only at that point that they had to synthesize vitamin D from the sun more readily. This explains why the Inuit in the Arctic circle kept a dark pigmentation in a low light climate and avoided vitamin D deficiency.
The northern Europeans made wheat a staple. Wheat contains an anti-nutrient called WGA, a lectin that binds to cellular glycoproteins. Once in the gut, WGA binds to a cell receptor, and then a nuclear pore found in every cell in the body that blocks the transport and absorption of vitamin D. Fast forward to the modern era, where wheat is still a staple and our lives have moved indoors, affecting vitamin D levels, absorption, and transportation.
What Does Your Nutrition Genome Report Say About Sun Protection?
The Nutrition Genome Report looks at TP53 and MDM2 for DNA repair for sun damage. The mutations in these genes are environmental trade-offs. Researchers believe that heterozygous and homozygous variants in these mean less protection against UV radiation in exchange for higher fertility rates in cold climates. It is an environmental adaptation for procreation, however, as many of us moved to warm southern climates, this adaptation makes us more prone to skin damage from excess sun exposure.
If you have lighter skin and variants in these genes, niacin, zinc, and selenium are the three major vitamins and minerals needed to improve TP53 function, while vitamin D and the vitamin D receptor (VDR) function improve MDM2 expression. What is interesting about this is that fish is an excellent source of zinc and selenium (and cod liver a source of D), while providing omega-3 fatty acids.
An Australian study showed a 40 percent reduction in melanoma for those who were eating fish. Recently, the National Academy of Sciences published a comprehensive review showing that the omega 6:3 ratio was the key to preventing skin cancer development. Wild salmon is especially a great choice due to astaxanthin. Research shows that astaxanthin prevents cancer initiation by protecting DNA from ultraviolet and oxidant damage, reduces liver fat and triglycerides, reduces the impact of glycation, and keeps skin young.
Other Dietary Strategies for Sun Protection and DNA Repair
Nature provides what you need for each season. In the summer, berries are plentiful and rich in vitamin C and ellagic acid. Vitamin C has been found in studies to epigenetically reprogram melanoma cells, whereas several studies show ellagic acid can inhibit the growth of tumors of the skin.
Many people are unaware that sun exposure depletes folate levels, and folate is crucial for healthy DNA. If you are getting a lot of sun and have higher genetic requirements for folate, you will want to focus more on your folate-rich vegetables (strawberries also have folate) in the summer. An association of green leafy vegetables with decreased risk of skin cancer has been reported, and a higher consumption of fruits and vegetables was related to a decreased risk of skin cancer by 54%.
What would summer be without watermelon? One study found that lycopene was photoprotective, and inhibits proliferation of several types of cancer cells. Watermelons have 40 percent more lycopene than tomatoes, and this water-rich fruit can help hydrate and protect you from sunburns and sun damage.
Finally, more good news for chocolate lovers. Chocolate has become recognized as an antioxidant-rich food that can help shield the skin against sun damage. One study found that dietary flavanols from cocoa contribute to endogenous photoprotection, improves dermal blood flow, hydration and complexion.