The sun is an amazing ball of fire and gas that we greatly undervalue, and then when it does come out, we complain about the heat. Other than being able to wear summery clothes and fashionable sunglasses, the sun has so many advantageous benefits for our health, and also has a lot of misconceptions when it comes to sunlight exposure. I am going to clear up the myths in this article.
On one hand we have people limiting their sunlight exposure due to the concern they may develop skin cancer, and others that consequently get numerous conditions related to Vitamin D deficiencies. Sun light is essential for our health, and too many people are afraid. The media say wear suncream, the media say the sun causes skin cancer… When was the last time you trusted the media? It’s nonsense.
Early on, in the oldest research related to sunlight exposure, they found that it cured Rickets disease (a bone disease). Vitamin D deficiency increases destruction of the human skeleton, vis osteopenia and osteopertic mechanisms. [1]
Around the 1930s scientific attention started to urge towards the risks of ultraviolet exposure, which was a huge, incorrect turn for the worse. This along with the rapid growth in the sunscreen industry was only making matters worse (chemical sunscreens were developed in 1928), in my opinion anyway. Finally, recent literature is focusing more on the benefits of adequate sun exposure, and not the theorised risks. The cause of melanoma (skin cancer) is still unknown, but it is thought to be mainly genetic [2].
Non-burning sun exposure is linked to less risk of melanoma (obviously sizzling in the sun will cause all sorts of damage). Furthermore, outdoor workers have been shown to have a much lower risk of developing skin cancer than indoor workers [3], who are outside exposed to direct sunlight all day.
Our body is biologically predisposed to damage through exposure to UVB, but we are clever. As with all physiological systems, we have adaptive responses to counteract such damage. Eventhough we may get oxidative damage through he production of free radicals from the sun, our body has built in mechanisms to deal with this, and these mechanisms thrive off Vitamin D. These mechanisms include DNA repair, reduced cell proliferation, regulatory mechanisms of cellular death and recycling, as well as anti-inflammatory benefits. So, reduce exposure to sunlight, reduce vitamin D synthesis and consequently be more at risk from the damage UVB may have caused [4]. Ultimately, reducing our exposure to the sun may increase or speed up our susceptibility to disease.
We must understand that Vitamin D is a hormone, and most cells in the entire human body have Vitamin D receptors, which means the vitamin must play a vital role in the functioning if all cells. Limit the amount of VD to the cell, impair the function, and consequently result with numerous conditions linked with deficiency.
Vitamin D Deficiency:
In one study carried out to find the relationship between Vitamin D levels and all-cause mortality, they found an inverse association of circulating 25(OH)D [vitamin D] with risks of death due to cardiovascular diseases, cancer and other causes [5]. So limit your sun exposure, and you will find yourself heightening your risk of early mortality. The same study proved numbers of European VD deficiency to be 86.4%. Meaning 86.45% of all europeans need to be getting more sunlight.
Cardiovascular Disease: The highest, global mortality rate.
In a study done on UVA radiation and the link to CVD, it shows that the benefits of the exposure are seen even before the need for VD synthesis [6]. It is not surprising that the cases of CVD rise in the winter. It is theorised that the exposure to UVA on our skin mobilised Nitric Oxide bioactivity into the bloodstream and will have vasodilatory effects, leading to reduction in blood pressure, and consequently lowering the risk of heart diseases.
Metabolic Syndrome and T2B:
It has been shown that higher levels of Vitamin D are associated with lower risk of metabolic syndrome; Hypertension, Cholesterol, Blood Sugar Regulation issues, Obesity etc… [7]. Type 2 Diabetics will also benefit from increases sun exposure, as another huge study performed on over 70,000 participants, showed an inverse correlation between higher levels vitamin D and reduced chance in developing T2B, this was backed up by further studies showing a 43% lower risk of T2B with increased levels of VD [8]
There are also numerous studies proving the benefit of sunlight exposure for many brain derived and neurological diseases, various cancers, skin conditions, liver disease and so on, the list is endless.
STOP BUYING SUNSCREEN:
Sunscreen is a widely though preventative measure of skin cancer. WRONG. There is no epidemiological studies that prove this, and its actually quite the opposite.
There are extremely few studies and a theorised body of literature that actually support the use sunscreen. I mean the studies show that some sunscreen reduces non-melanoma tumors….in rats…
There is no direct relationship, or significant decrease in risk of melanoma with the use of sunscreen, period [9]. Infact, the majority of the literature out there actually states that people are at higher risk on melanoma with the use of sunscreen [10]. The reason behind this is probably due the fact sunscreen can block the potential beneficial effects that vitamin D posses in all of the aforementioned mechanism to regulating damage (anti-inflammatory, apoptosis, DNA repair and cellular recycling etc..)
Conclusion:
Its pretty simple - look at the vast bodies of evidence that prove there are relentless benefits to sun exposure, the correlating reduced risk of all-cause mortality and reduced susceptibility to contracting many diseases. Then look at the 1 or 2 studies that show increased risk of sun exposure and skin cancer in rats. The benefits that vitamin D brings far outweigh the non-existent consequences of sun exposure, more so the studies that prove sun screen can also have a undesired effect in increasing our risk of skin cancer.
Take-aways:
Adequate levels of sun are essential, and time spent in the sun should be controlled, as obviously burning is undesirable, painful and looks bad. Increasing the amount of sun exposure as possible while controlling for sun-burn would be advised for optimal health. Using sun screen may have many disadvantages and very few, unsupported benefits. A little bit of red-ness is fine, as its not necessarily skin damage, but just the body reaction to heat. Allow our body to do its thing. Remember, if we do get a little burnt, we have adaptive cellular mechanics to counter act the effects, and wearing sunscreen or staying out of the sun may prevent these processes.
[1] Holick MF. Deficiency of sunlight and vitamin D. BMJ. 2008;336(7657):1318-1319. doi:10.1136/bmj.39581.411424.80
[2] Nelson AA, Tsao H. Melanoma and genetics. Clin Dermatol. 2009;27(1):46-52. doi:10.1016/j.clindermatol.2008.09.005
[3] Gandini S, Sera F, Cattaruzza MS, et al. Meta-analysis of risk factors for cutaneous melanoma: II. Sun exposure. Eur J Cancer. 2005;41(1):45-60. doi:10.1016/j.ejca.2004.10.016
[4] Fleet JC, DeSmet M, Johnson R, Li Y. Vitamin D and cancer: a review of molecular mechanisms. Biochem J. 2012;441(1):61-76. doi:10.1042/BJ20110744
[5] Chowdhury R, Kunutsor S, Vitezova A, et al. Vitamin D and risk of cause specific death: systematic review and meta-analysis of observational cohort and randomised intervention studies. BMJ. 2014;348:g1903. Published 2014 Apr 1. doi:10.1136/bmj.g1903
[6] Liu D, Fernandez BO, Hamilton A, et al. UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase. J Invest Dermatol. 2014;134(7):1839-1846. doi:10.1038/jid.2014.27
[7] Vitezova A, Zillikens MC, van Herpt TT, et al. Vitamin D status and metabolic syndrome in the elderly: the Rotterdam Study. Eur J Endocrinol. 2015;172(3):327-335. doi:10.1530/EJE-14-0580
[8[] Mitri J, Muraru MD, Pittas AG. Vitamin D and type 2 diabetes: a systematic review. Eur J Clin Nutr. 2011;65(9):1005-1015. doi:10.1038/ejcn.2011.118
[9] Gorham ED, Mohr SB, Garland CF, Chaplin G, Garland FC. Do sunscreens increase risk of melanoma in populations residing at higher latitudes?. Ann Epidemiol. 2007;17(12):956-963. doi:10.1016/j.annepidem.2007.06.008
[10] Autier P, Doré JF, Schifflers E, et al. Melanoma and use of sunscreens: an Eortc case-control study in Germany, Belgium and France. The EORTC Melanoma Cooperative Group. Int J Cancer. 1995;61(6):749-755. doi:10.1002/ijc.2910610602
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