Human beings never used sunscreen in the past. Don’t you think that using sunscreen could be more harmful than beneficial? 

Your question, although interesting, puts me in a bit of an awkward situation. In fact, I must confess that I personally never use sunscreen, whether by principle or by habit, I can't say.  That said, your question is important because it underlines the fact that many people still have doubts about the importance of protecting themselves from the sun. Yet, among light-skinned people, skin cancer⁽¹⁾ is now the most common form of cancer. ⁽²⁾

Points to consider

In response to your question, I cannot do more than offer you an overview of what’s at stake as well as several points to reflect upon that will, I hope, help you evaluate the various elements at play when examining this very important subject. As you will see, there is no definite answer.

A bit of history

Love of the sun or of sunshine, if you prefer, is nothing new.  In fact, promoters of natural approaches to health have always encouraged us to get enough sun. Even as far back as Hippocrates physicians have been lauding the virtues of heliotherapy, or the therapeutic use of sunlight. ⁽³⁾ In one of his books, Hippocrates recommends walking in the nude to take advantage of the health and sedative effects of the sun.

Naturopaths have praised the health benefits of the sun and natural Hippocratic philosophy has been quick to acknowledge it as well. 

Paul Carton

The French physician, Paul Carton, said “By tanning the skin, man assimilates and stores the force of the sun in the form of a brown pigment.” ⁽⁴⁾

André Passebecq

This well-known French naturopath wrote “Nature surely wanted man to live in the nude… was it not the intention of the Creator that every being live in contact with the sun?”  ⁽⁵⁾

Raymond Barbeau

This naturopath from Quebec, who many consider to be, and not without reason, the father of naturopathy in Quebec, dedicated an important part of chapter 11 of his book “Votre santé par la naturopathie” (Your Health through Naturopathy) to sunlight therapy. “Heliotherapy is an art of great importance which dates back to the beginning of humanity.  The sun has its worshippers.  It is the best medicine, according to Hippocrates. ⁽⁶⁾

Charles Atlas

The man who created one of the most long-lasting fitness programs of all time noted in the 7th lesson of his course “Whenever possible, get fresh air by basking in the sun.” ⁽⁷⁾

Natural health and sunbathing have always been intimately linked.  It is otherwise interesting to note that the term “naturist”, which was at first used to refer to those who wanted to live a natural lifestyle, has become almost exclusively synonymous with nudism. ⁽⁸⁾ Incidentally, one of the first movements dedicated to natural health in Quebec, founded by Dr Jean-Marc Brunet, was known as the Social Naturist Movement.⁽⁹⁾

Sunlight as therapy 

The best documented effect of sunlight is the production of Vitamin D⁽¹⁰⁾.  Indeed, in the human body, Vitamin D is produced from 7-dehydrocholesterol which is then converted to Vitamin D when skin is exposed to the ultra-violet rays of the sun.  As we know, increased production of Vitamin D promotes bone density, boosts the immune system, enhances mood and cardiovascular health ⁽¹¹⁾  and even seems to improve the health status of patients suffering from auto-immune diseases.⁽¹²⁾ 

Given all these benefits, the question we now need to ask ourselves is “Why use sunscreen?”

Depletion of the ozone layer 

The depletion of the ozone layer is, without a doubt, the best-documented environmental phenomenon contributing to skin cancer.  With the thinning of this protective layer, levels of potentially carcinogenic UV rays are on the rise and are leading to a verifiable epidemiological increase in skin cancer. ⁽¹³⁾

For the most part, protagonists of sunscreen use this theory of ozone depletion to develop their argument.  They maintain that although sunlight is natural and beneficial, the high levels of UV rays now penetrating our atmosphere are not.  If our sunlight has now become unnatural, we can no longer depend on natural elements to protect us.  Sunscreens have become, according to this way of thinking, a necessary evil. ⁽¹⁴⁾

The proliferation of environmental pollutants 

Despite the fact the depletion of the ozone layer is the best documented factor regarding skin cancer, it is only one among many.  The presence of various chemical substances which did not exist in the natural environment a thousand, or even a hundred, years ago is not without significance in the development of skin cancer. ⁽¹⁵⁾ 

The argument here, as for the depletion of the ozone layer, is that the skin must be protected to counteract these foreign substances (we have referred to xenobiotics in this magazine in the past) as many of these appear to intensify the carcinogenic effects of UV radiation.  

Color of the skin 

Individuals with dark skin are less likely to develop skin cancer because melanin, the protein which colors the skin, protects the skin against the oxidative effects of UV radiation.  These variations between different ethnic groups and races have been pointed out by the U.S. Center for Disease Control and Prevention, among others.  A tan-skinned person like me has less to worry about than someone with a more Nordic complexion.  This is another factor to take into consideration when it comes to sun exposure. 

Progressive sun exposure 

Intensive rather than progressive sun exposure is a relatively recent phenomenon in the history of humanity.  Indeed, a thousand years ago a white-skinned Caucasian could not leave his cold climate and in a matter of hours be basking in the tropical sun.  For light-skinned people such as the natives of Scandinavia, for example, sun exposure was progressive with the coming of the summer season.  Therefore, the skin would gradually adapt to the increasing intensity of the sun.   

Therefore, a number of factors must be taken into consideration when evaluating the impact of sun exposure on our skin, as well as making the decision whether or not we should use sunscreen.  From a medical standpoint, the vast majority of experts agree that sunscreens should be used. ⁽¹⁷⁾ On the other hand, others warn about the disadvantages and inherent dangers of using these products. 

Anti-screens 

A study published in the International Journal of Cancer points out that individuals using sunscreen have just as much risk of melanoma as those that do not.  According to this study, people who use sunscreen spend more time in the sun as they believe the sunscreen protects them from the sun's harmful effects, thus increasing their risk of melanoma ⁽¹⁸⁾.  A similar study comes to the conclusion that sunscreens which only block UVB rays, and not UVA, increase the risk of skin cancer as well. ⁽¹⁹⁾

In both cases, the solution is simple.  First, don’t spend more time in the sun just because you’ve applied sunscreen. Second, make sure that the sunscreen you’re using protects against both UVA and UVB rays. 

The most troubling aspects of sunscreen use

Several studies have shown that certain nanoparticles and other ingredients commonly used in sunscreens can induce skin cancer. ⁽²⁰⁾  In version 2.0 of its monograph for sunscreens, Health Canada included the requirement that labels for sunscreens containing alpha hydroxy acids (AHA) and/or retinol say “...may increase your skin’s sensitivity to the sun and particularly the possibility of sunburn. Please limit sun exposure while using this product and for a week afterwards.” ⁽²¹⁾

An important number of studies emphasize that applying sunscreen to the skin may cause the formation of free radicals. ⁽²²⁾ The problem here is free radicals cause damage to DNA which can accelerate the aging of the skin (23) and promote the development  of skin cancer ⁽²⁴⁾.

This production of oxygen radicals, or free radicals, poses the greatest problem with the safe use of sunscreen. If we don't use them, we risk developing skin cancer and if we use them, we risk developing skin cancer. We're "damned if we do and damned if we don't."

What can I do?

If you decide to use sunscreen 

Use a sunscreen product with an excellent Sun Protection Factor (SPF) and with a “broad spectrum” that protects against both UVA and UVB.  The quality of sunscreen products varies greatly, inform yourself and choose wisely. 

Do not spend more time in the sun just because you have applied sunscreen.

Once you are out of the sun, wash the skin well to remove any particle residues.

Increase consumption of antioxidants, notably Vitamins A, C and E and selenium as well as flavonoids and various carotenoids. Beta-carotene, a precursor to Vitamin A, is especially indicated.  If you decide to take a supplement, opt for one that has a complete array of antioxidants so as to benefit from the synergistic effects of the nutrients. 

Note that the use of topical antioxidants, agents designed to be applied directly on the skin, significantly increase the concentration. The concentration of Vitamin C that is absorbed by the skin, for example, is 20 to 40 times greater than what is obtained when taken orally.⁽²⁵⁾

Finally, opt for a sunscreen that contains natural trace-elements such as zinc and titanium oxide rather than formulations which use chemical blocking agents. 

If you decide not to use sunscreen 

Increase your exposure to the sun gradually. The paler the skin, the more gradual the sun exposure should be. Opt for short sessions and spread them out over a period of several days.  

Do not remain in the sun for extended periods of time. Take frequent breaks in the shade. 

If you do get a sunburn, quickly apply aloe vera gel to reduce inflammation and protect the skin from further damage.

Be sure to drink plenty of water. 

Increase consumption of antioxidants. Refer to number 4 of the previous section. 

Finally, the use of topical antioxidants as mentioned above protects and can even reverse damage to the skin. ⁽²⁶⁾

References

^1. Note that even though there are different types of skin cancer, I will use the word cancer in the singular as this article does not make any distinction between the different types of skin cancer. 

^2. T.L. Diepgen andV. Mahler The epidemiology of skin cancer British Journal of Dermatology Volume 146, Issue Supplement s61, pages 1–6, April 2002

^3. Woloshyn, Tannia Anne Our Friend the Sun, Osler Library of the History of Medicine, McGill University (2011) 

^4. Vasey, Christopher L’Hippocrate du XX siècle, Le Message du Dr. Carton, Éditions Trois Fontaines (1992)

^5. Passebecq, André Les facteurs naturels de santé, Tome II, Vie & Action (1984)

^6. Barbeau, Raymond Votre santé par la naturopathie Éditions Natura (1967)

^7. Atlas, Charles DYNAMIC-TENSION® bodybuilding and fitness course are ©2000 Charles Atlas, Ltd.

^8. Arnaud Baubérot, Histoire du naturisme : le mythe du retour à la nature, Presses universitaires de Rennes, 2004

^9. Notice biographique, Bibliothèque et Archives nationales du Québec http://pistard.banq.qc.ca/unite_chercheurs/description_fonds?p_anqsid=201012091228231181&p_centre=06M&p_classe=P&p_fonds=264&p_numunide=2231.

^10. Wacker M, Holick MF. Sunlight and Vitamin D: A global perspective for health. Dermatoendocrinol. 2013 Jan 1;5(1):51-108

^11. M. Nathaniel Mead, Benefits of Sunlight: A Bright Spot for Human Health, Environ Health Perspect. 2008 Apr; 116(4): A160–A167

^12. Michael F Holick Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease, Am J Clin Nutr December 2004 vol. 80 no. 6 1678S-1688S

^13.  Figueroa, F. López , Climate Change and the Thinning of the Ozone Layer: Implications for Dermatology  Actas Dermo-Sifiliográficas (English Edition) 2011, Vol.102(5):311–315, doi:10.1016/S1578-2190(11)70813-7

^14. Barbara  A.  Gilchrest    Sun  protection  and  Vitamin  D:  Three  dimensions  of  obfuscation   The Journal  of  Steroid  Biochemistry  and  Molecular  Biology  March  2007,  Vol.103(3):655–663p

^15. C.  Baudouin,  M.  Charveron,  R.  Tarroux,  Y.  Gall,  Environmental  pollutants  and  skin  cancer,  Cell Biology  and  Toxicology10-2002,  Volume  18,  Issue  5,  pp  341-348

^16. Skin  Cancer  Rates  by  Race  and  Ethnicity,  Centers  for  Disease  Control  and  Prevention,  révisé  27 août 2014 (http://www.cdc.gov/cancer/skin/statistics/race.htm) 

^17. Burnett  ME1,  Wang  SQ.,  Current  sunscreen  controversies:  a  critical  review.  Photodermatol Photoimmunol  Photomed.  2011  Apr;27(2):58-67.  doi:  10.1111/j.

^18. Johan  Westerdahl,  Christian  Ingvar,  Anna  Måsbäck  and  Håkan  Olsson  Sunscreen  use  and malignant  melanoma  International  Journal  of  Cancer  Volume  87,  Issue  1,  pages  145–150,  1  July 2000

^19. Edward  D.  Gorham,  Sharif  B.  Mohr,  Cedric  F.  Garland,  Do  Sunscreens  Increase  Risk  of Melanoma  in  Populations  Residing  at  Higher  Latitudes?  Annals  of  Epidemiology,  December 2007 Volume  17,  Issue  12,  Pages  956–963 

^20. NTP  TECHNICAL  REPORT  ON  THE  PHOTOCOCARCINOGENESIS    STUDY  OF    RETINOIC  ACID  AND RETINYL  PALMITATE,    National  Institutes  of  Health  Public  Health  Service  U.S.  DEPARTMENT  OF  HEALTH AND HUMAN SERVICES  (2012) 

^21. Monographie  sur  les  écrans  solaires,  Direction  générale  des  produits  de  santé  et  des  aliments, 16  novembre  2012 

^22. Hanson  KM,  Gratton  E,  Bardeen  CJ  (October  2006).  Sunscreen  enhancement  of  UV-induced reactive  oxygen  species  in  the  skin.  Free  Radic.  Biol.  Med.  41  (8):  1205–1212. Elisabetta  Damiani,  Werner  Baschong,  Lucedio  Greci.  UV-Filter  combinations  under  UV-A exposure:  Concomitant  quantification  of  over-all  spectral  stability  and  molecular  integrity. Journal  of  Photochemistry  and  Photobiology  B:  Biology  87  (2):  95–104  (2007)  J.M.  Allen,  C.J.  Gosset,  A.K.  Allen.  Photochemical  formation  of  singlet  molecular  oxygen  in illuminated  aqueous  solutions  of  several  commercially  available  sunscreen  ingredients.  Chem. Res.  Toxicol.  9  (3):  605–609.  (1996)

^23. Stadtman  ER  (August  1992).  "Protein  oxidation  and  aging".  Science  257  (5074):  1220–4. 

^24. Cairns  RA,  Harris  IS,  Mak  TW  (February  2011).Regulation  of  cancer  cell  metabolism.  Nat.  Rev. Cancer  11  (2):  85–95 Waris  G,  Ahsan  H  (2006). Reactive  oxygen  species:  role  in  the  development  of  cancer  and various  chronic  condition.  J  Carcinog  5:  14.^25. Burke  KE  Photodamage  of  the  skin:  protection  and  reversal  with  topical  antioxidants.  J  Cosmet Dermatol.  2004  Jul;3(3):149-55   ^26. ibid.