The Benefits and Risks of Sun Exposure


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The media, cosmetic industry and public health authorities have been pushing for less sun exposure for fear of causing skin cancer. Yet, over the last two decades, there has been a steady increase in global vitamin D deficiency and insufficiency (Hoel, D.G., et al., 2016). 

Moderate non-burning sun exposure is needed to keep vitamin D at sufficient levels in the body. Moderate sun exposure also aids in balancing mood, strengthening bones and much more. With most of us spending more and more time indoor, work alone accounting for between 30-45 years, inadequate sun exposure can have drastic implications on our adult lives (Baczynska, K.A., 2018).

What is Sunlight and Why is it Important? 

Sunlight is solar radiation, which consists of visible light, ultraviolet light and infrared radiation. Cloud cover, time of day and season all affect the amount of radiation that hits the earth at a particular time. The smallest proportion of sunlight is made up of UV radiation, such as UVA and UVB. UVB radiation handles the production of active vitamin D by the body. 

Vitamin D is a hormone that is needed by most cells in the body. This has led to a link between several diseases and vitamin D deficiency such as psoriasis and arthritis. Vitamin D promotes bone health, a positive mindset, the synthesis of melatonin and serotonin, as well as strengthening and protecting the skin through DNA repair and lowering the risk of cancer (van der Rhee, H., et al., 2016). 

Exposure duration and the time of sun exposure are important to take into account. At the beginning of the summer season start with 5-10 minutes of moderate sun exposure. Increasing your exposure day by day is optimal instead of outright prolonged sun exposure (Stern, R.S., 2017). 

Benefits of Moderate Sun Exposure on the Body 

Moderate sun exposure, along with supplementation though diet and vitamin D3 drops when sun exposure is not possible, is essential for maintaining serum vitamin D3 levels.

Sports Nutrition and Joint Health

Sun exposure has been shown to boost athletic performance. Sun exposure promotes bone and musculoskeletal health, enhances immune function, reduces the risk of fractures, as well as the production of adequate levels of testosterone. Deficiencies of serum D3 can result in joint pain and an increase in stress fractures (Miraj, S.S., et al., 2019). 

Gut health and UV Exposure

A 2019 study looked at the association between inflammatory bowel disease and lack of sun exposure, particularly in young children. Although more research needs to be done in this area there is a relation between immune health and gut health. Adequate vitamin D3 serum levels play an important roll in boosting immune performance. Most individuals who suffer from IBD, both children and adults, are deficient in vitamin D3. Having adequate serum levels of vitamin D3 may potentially reduce the risk of developing IBD (Holmes, E.A., et al., 2019). 

Anti-inflammatory Benefits of the Sun 

Sun exposure apart from boosting the immune system, also aids in reducing inflammation as well as stimulating immunosuppressive pathways in the body. Autoimmune diseases, such as psoriasis are most common amongst individuals who live further from the equator and are often seen in people with a deficiency in vitamin D. Lack of UV exposure can be a risk factor for such autoimmune and inflammatory diseases (Hart, P.H., et al., 2019).  

UVA and UVB Radiation 

Free radical damage occurs at all levels of radiation, but the body has natural defences to prevent the radiation from negatively affecting our skin. These defences include;

  • DNA repair mechanisms
  • Cell cycle and growth inhibition
  • Reduced proliferation
  • Enhanced sensitivity to apoptosis 
  • Anti-inflammatory effects

UVB radiation consists of short wavelengths that induce DNA damage through the creation of pyrimidine dimers.  When UVB causes a sunburn it can affect the immune system, as well as lead to pigmentation, inflammation and photocarcinogenesis. It is necessary for the production of vitamin D through the skin into its active form as well as via the liver and kidneys (Hoel, D.G., et al., 2016) (Latha, M.S., et al., 2013) (Godar, D.E., et al., 2009) (Stern, R.S., 2017).  

UVA radiation consists of long wavelengths and has a similar effect on the skin to UVB however, it also creates oxidative stress/damage. It negatively affects skins elasticity and collagen, resulting in wrinkles and faster ageing. When sunburns develop it increases inflammation (Hoel, D.G., et al., 2016) (Stern, R.S., 2017). 

skin and UVA and UVB rays

Sun Exposure and Melanoma

As with an increase in vitamin D deficiency globally, there is also an increase in melanoma cases. Although sun exposure produces vitamin D which is essential for good health as well as protecting skin from damage, the wrong kind of sun exposure can be detrimental. 

Cutaneous malignant melanoma incidences have increased since the 1940s with most cases of melanoma occur on the torso and the legs, areas of the body that are often covered by clothing. The face and hands have the lowest incidence of melanoma although they are areas that receive the most sun exposure. Those most at risk are fair-skinned individuals and indoor workers. People who work or spend most of their time indoors have 3-9 times less UV exposure than outdoor workers (Godar, D.E., et al., 2009).

Research has found that outdoor workers have lower incidence of skin cancer, whereas individuals who spend more of their time indoor have an increased risk, of between 25-75% more than outdoor workers (Hoel, D.G., et al., 2016). An Australian study from 2014 found that outdoor workers did not increase their chances of developing melanoma even of the neck and face (Vuong, K., et al.). 

Ozone depletion, the increased use of tanning beds and large office windows are recent changes that have been affecting the population for the last decade or so and subsequently negatively affect the skin. Some windows reflect UVA and UVB radiation, most allow a small amount of UVA radiation to filter through. Exposure to UVA without adequate exposure to UVB can cause mutations to vitamin D3 and increase cutaneous malignant melanoma (Godar, D.E., et al., 2009).

It is the type of sun exposure that one gets that increases the risk of developing melanoma.  Moderate sun exposure for individuals who spend most of there time indoors is safe, as long as it does not result in sunburn (Elwood, J.M., et al., 1997). 

The prevalence of melanoma may be due to several factors including spending more time indoors, not receiving moderate sun exposure and a poor diet. 

sun exposure at the beach

How Sunburns Negatively Affect the Skin

Sunburns are painful, they cause skin peeling and damage the appearance of the skin. They also result in cell division and cell mutation (Hoel, D.G., et al., 2016). Sunburns lead to photoaging, which is the sagging, wrinkling and photocarcinogenesis of skin. Skin naturally loses its elasticity as we age, sunburns, which damage skin cells accelerate this process (Latha, M.S., et al., 2013). 

Sunburns increase the risk of melanoma as well as nonmelanoma skin cancers such as basal cell carcinoma and squamous cell carcinoma (Hoel, D.G., et al., 2016) (Kennedy, C., et al., 2003). Incidence of sunburns increases at higher latitudes, this is usually due to seasonality and working indoors. When people do have a chance to go outside it is usually only during the summer and on weekends. There is no slow introduction to sun exposure which would allow the skin to build up vitamin D stores, instead, the skin gets shocked by high UVA and UVB radiation (Gandini, S., et al., 2005). 

Some studies have shown that sunburns before the age of 20 increase the risk of malignant melanoma (Kennedy, C, et al., 2003), while others have found that a sunburn at age has been shown to express great risk for the development of melanoma (Elwood, J.M., et al., 1997). With the American Academy of Dermatology estimating that one in five Americas will develop cancer in their lifetime it is important to practise safe moderate sun exposure. If you live away from the equator, during warmer weather increase your exposure to the sun in small increments, if you are spending the day at the beach apply sunscreen and consume foods that fight free radical damage, and make sure to check your vitamin D levels and supplement with vitamin D3 if you are deficient or have an insufficient supply.

Sunscreen 

Sunscreens use photoprotective agents to minimize skin damage due to UVA and UVB radiation. Yet, they are now been shown to have negative environmental effects as well as being human contaminants.

Recent studies have found that certain compounds are negatively affecting sperm function in men potentially increasing the rates of infertility (Rehfeld, A., et al., 2018), the same UV reflective chemicals are now becoming commonly present in breast milk (Schlumpft, M., et al., 2010) this all may be a result of the fact that too much sunscreen is applied.  A 2019 study found that the recommended daily amount of sunscreen was over the recommended safe daily limit for the UV reflective chemicals that are present within it (Matta, M.K., et al., 2019). If you are at the beach for the whole day and you need to reapply sunscreen every hour or so you are most likely getting too much oxybenzone or Retinyl Palmitate into your system. 

Sunscreen does protect the skin from sun damage, but the right type of sunscreen needs to be used. Switching to a natural sunscreen free from synthetic chemicals is a much better option as well as seeking shade when the sun is at its peak. Making sure to be conscious of how much time you spend in the sun, especially if you are mostly indoors.

Chemicals to be wary of in sunscreen include the following;

  • Oxybenzone
  • Avobenzone
  • Ocitisalate
  • Octocrylene
  • Homosalate
  • Retinyl Palmitate  
  • Fragrance
  • Parabens
  • Phthalate
  • Octinoxate
Sunscreen

Foods and Sun Exposure 

Besides sunscreen, it is important to incorporate other skin protective methods into your sun exposure regime. Adding in antioxidants, essential fatty acids and ensure that you are well hydrated. 

Most ageing is attributed to free radical damage and oxidative stress. They are brought on by what we eat such as processed foods and environmental factors such as UV exposure (McDaniel, D.H., et al., 2019). The skin has endogenous defences against the sun. They are not perfect and so free-radical damage will occur. Antioxidants help to enhance this protection before and after sun exposure (Singer, S., et al., 2019). 

Topical antioxidant serums can be beneficial, as long as they contain natural ingredients. This can include botanical oils, such as sea buckthorn as well as certain vitamin C and E serums (Drapeau, C., et al., 2019)(McDaniel, D.H., et al., 2019). Applying topical antioxidant along with natural sunscreen is a great way to reduce photoaging and free radical damage to the skin. 

The consumption of antioxidant-rich foods is another wonderful way to reduce free radical damage and oxidative stress. Adding powders to smoothies such as camu camu, acai and spirulina can provide a quick and easy antioxidant boost.

Blueberries are fantastic fruits that have a positive impact on brain, eye and heart health, as well as increasing the effectiveness of anti-inflammatory markers in the body, reducing oxidative stress and boosting the immune potential of the body. Consuming blueberries can be a great way to get an antioxidant boost into the body and reduce the effects of UVR on the skin (Kalt, W., et al., 2019). Red raspberry extract as a topical application on the skin has been shown to be beneficial at reducing oxidative damage to DNA, inflammation and overall free radical damage, reducing the effects of UVR photoaging and damage to the skin (Wang, P.W., et al, 2019). 

References

Baczynska, K.A., Khazova, M., O’Hagan, J.B. (2019). Sun exposure of indoor workers in the UK – survey on the time spent outdoors. Photochemical and Photobiological Science. Volume 18, pages 120-128.  

DiNardo, J.C., Downs. C.A. (2018). Dermatological and environmental toxicological impact of the sunscreen ingredient oxybenzone/benzophenone-3. Journal of Cosmetic Dermatology. Volume 17, Issue 1. pages 15-19. 

Drapeau, C., Benson, K. F., & Jensen, G. S. (2019). Rapid and selective mobilization of specific stem cell types after consumption of a polyphenol-rich extract from sea buckthorn berries (Hippophae) in healthy human subjects. Clinical interventions in aging14, 253–263. 

Edwards, M.H., Cole, Z.A., Harvey, N.C., Cooper, C. (2014). The Global Epidemiology of Vitamin D Status. The Journal of Ageing Research and Clinical Practice.  

Elwood, J.M., Jpson, J. (1997). Melanoma and sun exposure: an overview of published studies. International Journal of Cancer. Volume 73, issue 2, page 198-203.

Gandini, Sara et al. Meta-analysis of risk factors for cutaneous melanoma:II.Sun Exposure. Eurpean Journal of Cancer. Volume 41, Issue 1, pages 45-60. 

Godar, D.E., Landry, R.J., Lucas, A.D. (2009). Increased UVA exposure and decreased cutaneous Vitamin D(3) levels may be responsible for the increased incidence of melanoma. Medical Hypotheses. Volume 72, Issue 4, pages 434-443.

Hart, P.H., Norval, M., Byrne, S.N., Rhodes, L.E. (2019). Exposure to Ultraviolet Radiation in the Modulation of Human Diseases. Annual Review of Pathology: Mechanisms of Disease. Volume 14, pages 55-81. 

Hoel, D. G., Berwick, M., de Gruijl, F. R., & Holick, M. F. (2016). The risks and benefits of sun exposure 2016. Dermato-endocrinology8(1), e1248325.

Holmes, E.A., Harris, R.M.R., Lucas, R.M. (2019). Low Sun Exposure and Vitamin D Deficiency as Risk Factor for Inflammatory Bowel Disease, With Focus on Childhood Onset. Photochemistry and Photobiology. Volume 95, Issue 1, pages 105-118. 

Kalt, W., Cassidy, A., Howard, L.R., Krikorian, R., Stull, A. J., Tremblay, F., Zamora-Ros, R. (2019). Recent Research on the Health Benefits of Blueberries and Their Anthocyanins. Advances in Nutrition. 

Kennedy, C., Bajdik, C.D., Willemze, R., De Gruijl, F.R., Bouwes Bavinck, J.N. (2003). The Influence of painful sunburns and lifetime sun exposure on the risk of actinic keratoses, seborrheic warts, melanocytic nevi, atypical nevi, and skin cancer. Journal of Investigative Dermatology. Volume 120, Issue 6, pages 1087-1093. 

Latha, M. S., Martis, J., Shobha, V., Sham Shinde, R., Bangera, S., Krishnankutty, B., … Naveen Kumar, B. R. (2013). Sunscreening agents: a review. The Journal of clinical and aesthetic dermatology6(1), 16–26.

Matta MK, Zusterzeel R, Pilli NR, et al. Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active IngredientsA Randomized Clinical TrialJAMA. Published online May 06, 2019321(21):2082–2091.

McDaniel, D. H., Waugh, J. M., Jiang, L. I., Stephens, T. J., Yaroshinsky, A., Mazur, C., … Nelson, D. B. (2019). Evaluation of the Antioxidant Capacity and Protective Effects of a Comprehensive Topical Antioxidant Containing Water-soluble, Enzymatic, and Lipid-soluble Antioxidants. The Journal of clinical and aesthetic dermatology12(4), 46–53.

Miraj, S.S., Thunga, G., Kunhkatta, V., Rao, M., Nair, S. (2019). Chapter 42 – Benefits of Vitamin D in Sports Nutrition. Nutrition and Enhanced Sports Performance. Muscle Building, Endurance and Strength. Pages 497-508. 

Moan, J., Porojnicu, A. C., Dahlback, A., & Setlow, R. B. (2008). Addressing the health benefits and risks, involving vitamin D or skin cancer, of increased sun exposure. Proceedings of the National Academy of Sciences of the United States of America105(2), 668–673.

Palacios, C., & Gonzalez, L. (2014). Is vitamin D deficiency a major global public health problem?. The Journal of steroid biochemistry and molecular biology144 Pt A, 138–145. 

Rehfeld, A., Egeberg, D. L., Almstrup, K., Petersen, J. H., Dissing, S., & Skakkebæk, N. E. (2018). EDC IMPACT: Chemical UV filters can affect human sperm function in a progesterone-like manner. Endocrine connections7(1), 16–25.

Schlumpf, M., Kypke, K., Wittassek, M., Angerer, J., Mascher, H., Mascher, D., Vokt, C., Birchler, M., Lichtensteiger, W. (2010). Exposure patterns of UV filters, fragrances, parabens, phthalates, organochlor pesticides, PBDEs, and PCBs in milk: correlation of UV filters with use of cosmetics. Chemosphere. Volume 81, Issue 10, pages 1171-1183. 

Singer, S., Karrer, S., Berneburg, M. (2019). Modern Sun Exposure. Current Opinion in Pharmacology. Volume 46, pages 24-28. 

Stern, R.S. (2017). Benefits of Moderate Sun Exposure. Harvard Health Publications. 

van der Rhee, H., de Vires, E., Coomans, C., van de Velde, P., Coebergh, J.W. (2016). Sunlight: For Better or For Worse? A Review of Positive and Negative Effects of Sun exposure. Cancer Research Frontiers. Volume 2, Issue 2, pages 156-183. 

Vuong, K., McGeechan, K., Armstrong, B. K., AMFS Investigators, GEM Investigators, & Cust, A. E. (2014). Occupational sun exposure and risk of melanoma according to anatomical site. International journal of cancer134 (11), 2735–2741.

Wang, P.W., Cheng, Y-C., Hung, Y-C., Lee, C-H., Fang, J-Y., Li, W-T., Wu, Y-R., Pan, Y-L. (2019). Red Raspberry Extract Protects the Skin Against UVB-INduced Damage with Antioxidative and anti-inflammatory Properties. Oxidative Medicine and Cellular Longevity. 

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