This is not how we evolved. Human beings did not stay in their caves all day! They spent their days outdoors hunting, gathering, playing, socializing etc.
Sufficient vitamin D is very difficult to get through food; as it would take three cans of sardines or fifty to one hundred egg yolks every day to get proper levels of vitamin D. This leaves supplementation or sunlight as the two remaining options.
Supplementation is not as effective as sun exposure at getting the body vitamin D, although it is better than nothing if the sun is not out. Sun exposure also happens to be completely free! It is important to note that UVB rays are the only bands of light that are able to produce vitamin D, and UVB rays are mostly present during midday sunshine. Because of this, it is important to get outside during the middle of the day!
Sunlight is synonymous in many people's minds with happiness. There is a reason for this. Sunlight boosts serotonin levels, which are critical to controlling mood. Sunlight also boosts dopamine levels, which lead to pleasure. It is also thought that getting adequate exposure to sunlight makes falling asleep at night easier, and helps regulate sleep cycles.
What are the other benefits of sunlight and vitamin D? Reducing risk of heart disease, hypertension, diabetes, multiple sclerosis, and dramatically boosting the immune system which we know protects the body against all sorts of diseases. Recent research shows that people of all ages were twice as likely to die within an eight year period if they had the lowest vitamin D levels compared to those with the highest vitamin D levels. Sunlight and vitamin D have also been shown to be essential to protecting against breast cancer, colon cancer, and pancreatic cancer. Sunlight and vitamin D also significantly increase survival rates of those who already have cancer.
And what about the deadly skin cancer: malignant melanoma? There is no evidence linking melanoma to sun exposure. In fact, melanoma appears frequently on body parts that have very little exposure to sunlight. In Japan 40% of melanomas on the feet are on the soles of the feet, and in Scotland there is 5 times more melanoma on the feet than on the hands. This makes sense when thinking about the United States as well: In 1900, about three quarters of the population worked outdoors, but melanoma was very rare. And in 1900 people definitely were not lathering on sunscreen. Additionally, a United States Navy study found that those who worked indoors has higher rates of malignant melanoma than those who worked outside. And like the above examples from Japan and Scotland, the Navy study also found that most of the cases of malignant melanoma occurred on parts of the body that did not get sun exposure.
One cannot talk about sun exposure without talking about sunscreen. Most chemical sunscreens do not actually stop UVA rays, which are involved in the creation of melanoma. Unfortunately, sunscreens do block skin from producing pigment melanin, which is what gives skin a natural sunblock: a tan. Sunscreens also block UVB rays, which are what stimulate vitamin D production. Even sunscreen with an SPF as low as 8 still blocks 95% of vitamin D production!
Most chemical sunscreens also contain benzophenone and psoralen, two of the most powerful free radicals in existence. So while the claim that chemical sunscreens prevent cancer is unproven, the possibility that these sunscreens are causing cancer is very real. In recent decades, the largest increases in melanoma have occurred in countries where sunscreens have been promoted the heaviest. Dr Cedric Garland and Dr Frank Garland of the University of California even believe the the increased use of sunscreens is the primary cause of skin cancer.
Sunscreens do protect against sunburns. It is unclear what sunburns can lead to, whether it be cancer or something less serious, but they are uncomfortable at the very least. Getting tan is one way to decrease the incidence of burning. Covering up with clothing or finding shade is another. But if you must use sunscreen, find a natural product rather than one full of harmful carcinogens.
Groves, Barry. Trick or Treat: How 'healthy Eating' Is Making Us Ill. London: Hammersmith, 2008. Print.
Croxton, Sean. "Return of the Prodigal Sun." Paleo Magazine July-Aug. 2011. Web.
Dowswell, Robert. "Sunlight and Vitamin D Improve Mood." DrDobbin Nutrition. Web. <http://www.drdobbin.co.uk/sunlight-vitamin-d>.
"Vitamin D, Sun, Skin Cancer." Arizona Center for Advanced Medicine. Web. <http://arizonaadvancedmedicine.com/articles/skin_cancer.html>.
"Melanoma." Arizona Center for Advanced Medicine. Web. <http://arizonaadvancedmedicine.com/articles/melanoma.html>.