IS THE SUN DANGEROUS? FOR MORE THAN 30 YEARS NOW, HERE'S WHAT WE'VE BEEN TOLD.
The ozone layer is thinner and has holes in it. It no longer protects us from the sun's harmful rays. The sun causes cancer and accelerated skin aging. It's dangerous! A "healthy tan" is a figment of the imagination. So, according to this view, we should apply high SPF (sun protection factor) sunscreen at least 30 minutes before going outside. Is this truly healthy behavior, or are we being trained to engage in potentially harmful behavior?
SUN FILTERS AND SUNSCREENS: FRIENDS OR FOLIES?
This question is very complex, and the answer is neither black nor white. There is only one absolute truth on which all stakeholders agree: you should not burn. It is sunburn that is a risk factor for skin cancers (and even then, not all skin cancers). The sun is like wine: a little is good, too much is too much. Moreover, to the great displeasure of sunscreen salesmen, the Canadian Cancer Society no longer recommends avoiding all exposure altogether: "Natural sunlight is essential for life; however, excessive exposure to the sun's rays can lead to skin cancer or eye problems. A little common sense in the sun can go a long way in keeping you and your loved ones healthy." » We could also read, in www.cyberpresse.ca of March 25, 2009, this news from Agence France-Presse: "We found that women who sunbathe have a 30% lower risk of suffering from blood clots," Pelle Lindqvist, associate professor in the department of gynecology and obstetrics at Karolinska University Hospital in Stockholm, told AFP. Here are the results of two studies that clearly show the importance of sun exposure for health.
SUN EXPOSURE AND RISK OF MORTALITY
Swedish researchers published a study in which they followed nearly 30,000 women aged 25 to 64 over a period of 20 years. They compared the women's behavior in relation to the sun and found that avoiding sun exposure increases the risk of mortality by two times (200%) compared to regular sun exposure (1). These figures are interesting, but it is important to remember that the study comes from Sweden, where the sun is a rare commodity. (For comparison, Stockholm's latitude is 59 degrees, while Montreal's is 45 degrees, so much further south.) However, they do show us the necessity of sun exposure for health.
SUNSCREEN AND RISK OF MELANOMA
Researchers wanted to evaluate the effect of sunscreen use on melanoma prevention. Their results were, to say the least, different from what they expected. When comparing people who always wear sunscreen with those who never do, we see that regular sunscreen use appears to increase the risk of malignant melanoma by about 80%. This increase in relative risk is terribly magnified in people who report using sunscreen to stay in the sun longer, multiplying the risk by almost 9 times (900%) (2) . The most plausible explanation for these results is probably the improper use of sunscreen. During prolonged sun exposure, it is important to apply sunscreen several times during the day, even if the chosen cream has a very high SPF. But this may not be the only explanation...
QUESTIONABLE INGREDIENTS IN SUNSCREENS (3)
Not all sunscreens are completely safe. Researchers are highlighting effects that aren't discussed enough. Some filters can have estrogenic activity, adding to the tide of hormone disruptors already attacking us. Some are unstable in light, penetrate the skin, and so on. See the sidebar for more information on these substances.
INGREDIENTS TO BE COMPLETELY BANISHED
PABA
Padimate O
These ingredients have already been abandoned by many manufacturers because they are allergenic. What you probably don't know is that they also have "photomutagenic" properties, meaning they can cause genetic changes in skin cells when exposed to light!
FILTERS WITH ESTROGENIC ACTIVITY (rat studies) (4,5)
Benzophenone-1 (BP-1), Benzophenone-2 (BP-2) 4-Methylbenzylidenecamphor (4-MBC) Benzophenone-3 (BP-3 or BZ-3 or oxybenzone) 3-Benzylidenecamphor (3-BC) Octyl-methoxycinnamate (OMC)
LIGHT UNSTABLE FILTERS
Oxybenzone (benzophenone-3) Octyl-methoxycinnamate (OMC)
FILTERS THAT CROSS THE SKIN BARRIER
Oxybenzone (benzophenone-3) 4-methylbenzylidene camphor (4-MBC) - weakly Octyl-methoxycinnamate (OMC) - weakly Titanium oxide (Depending on particle size: too fine
THE BENEFITS OF THE SUN
Sunshine is vital for our health. Lately, we've been hearing more and more about the many benefits of vitamin D. However, as people in the northern hemisphere, our vitamin D levels are often too low. According to Health Canada, 40% of us don't have adequate blood levels of vitamin D. Let alone optimal levels!
The sun's UVB rays are the only valid natural source of vitamin D. To stimulate vitamin D synthesis, sunlight is at its best between 10 a.m. and 2 p.m. between March and September. However, this is precisely the light we are urged to avoid at all costs, otherwise we could end up looking like the Colonel's chicken... It's enough to make you lose your Latin...
THE BENEFITS OF VITAMIN D
If it needs repeating, UVB rays, those that pass between 10 a.m. and 2 p.m., those that are claimed to be the horribly dangerous ones, are necessary for the production of vitamin D. The synthesis of this vitamin is associated with:
- less osteoporosis • less cancer (including some skin cancers) • less heart disease • less depression • a better immune system.
Ultimately, it's most important to know how our skin reacts to the sun and to make sure we don't burn. To produce vitamin D, we should get a daily dose of sun equivalent to a "minimal erythema dose." This dose of sun depends on your skin tone (and the UV index). If you're a pale blonde or redhead and you burn easily, this "dose" may only be 4-5 minutes. But if you're African-American with an ebony complexion, the Quebec sun, even in July, may not be enough.
Another factor to consider: skin surface area is important for vitamin D levels. If you only have your hands and face uncovered, you produce less of the vitamin than if you tan in a swimsuit.
OTHER BENEFITS OF THE SUN
The benefits of the sun are not limited to vitamin D. Beyond the feeling of well-being that the sun provides and the stimulation of vitamin D synthesis, exposure to ultraviolet B rays leads to the formation of other substances in the body, notably lumisterol (6) . Vitamin D and lumisterol have the ability to inhibit the formation of cancer induced by ultraviolet rays (6) . This adaptation mechanism of the skin, greatly underestimated by sunscreen enthusiasts, protects us from damage caused by the sun. Thus, during sun exposure, the skin has several means of protection by producing:
- melanin (the tanning pigment) which blocks UV penetration;
- vitamin D and lumisterol which work together to minimize the impact of rays on the skin.
Please note, I am not saying that these protection systems are infallible and that it is not possible to exceed their effectiveness limits. The appearance of inflammation and sunburn warns us when we exceed this limit.
ENJOY THE BENEFITS, WITHOUT THE HARMS
If the sun were as dangerous as some claim, the human race would have long since disappeared. Evolution has provided us with the tools to properly use and tolerate the sun. However, in our northern climes (and according to habits and customs in many warm countries), since the sun is no longer the constant companion it was at the dawn of humanity, we must adjust. Like almost everything good, the sun must be enjoyed in moderation, but regularly. Thus, prolonged spring exposure has a harmful effect on our skin, which almost immediately results in a nasty sunburn. Therefore, judgment is required.
There are ways to naturally protect yourself from the harmful effects of the sun. Sunscreens and creams, used wisely, remain useful and valuable tools for preventing sunburn. Yes, but which sunscreen?
THE RIGHT SUNSCREEN CHOICES
- Clothing • Sunglasses • Parsol 1789® alias avobenzone • Mexoryl® SX • Titanium oxide (except nanoparticles) • Zinc oxide
AND FOOD?
Diet plays an important role in reducing sun sensitivity and increasing defenses against cancer. Eat colorful, fresh, and especially plant-based foods, as Jacynthe suggests, and your internal defenses against sun damage will be much stronger.
IN CONCLUSION Remember that the sun is important for your health. You shouldn't be afraid of it. However, you shouldn't burn yourself. Sunscreen (not just any kind) is a useful tool, but not all the time. In short, here as elsewhere, moderation... Looking forward to meeting you outdoors... unless the smog keeps us indoors.
Info on: UV INDEX
During weather reports, we are bombarded with the UV index without really being explained. This index is a method for measuring the intensity of ultraviolet rays which, as we have just seen, are good for our health, but only in moderation. When we are told that an index of 7 is high, we need to know in relation to what. The scale of this index varies between 0 (winter) and 11+. (It can reach 15 in the Sahara.) You will understand that if in Quebec your minimum dose of erythema is 1 hour, at the equator it can be only a few minutes. So we come back to the notion of feeling, knowing your tolerance to the sun, etc.
References:
1. Schlumpf M, Schmid P, Durrer S, et al. Endocrine activity and developmental toxicity of cosmetic UV filters-an update. Toxicology. 2004 Dec 1; 205(1-2): 113-22.
2. Schlumpf M, Durrer S, Faass O, et al. Developmental toxicity of UV filters and environmental exposure: a review. Int J Androl. 2008 Apr; 31(2): 144-51.
3. Dixon KM, Norman AW, Sequeira VB, Mohan R, Rybchyn MS, Reeve VE, Halliday GM, Mason RS. 1alpha,25(OH)₂-vitamin D and a nongenomic vitamin D analog inhibit ultraviolet radiation-induced skin carcinogenesis. Cancer Prev Res (Phila). 2011 Sep; 4 (9): 1485-94. doi: 10.1158/1940-6207.CAPR-11-0165. PubMed PMID: 21733837. https://cancerpreventionresearch.aacrjournals.org/content/4/9/1485.long
4. Westerdahl J, Ingvar C, Mâsbäck A, Olsson H. Sunscreen use and malignant melanoma. Int J Cancer. 2000 Jul 1; 87(1): 145-50. PubMed PMID: 10861466. https://www.ncbi.nlm.nih.gov/pubmed/10861466
5. Lindqvist PG, Epstein E, Landin-Olsson M, Ingvar C, Nielsen K, Stenbeck M, Olsson H. Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort. J Intern Med. 2014 Jul; 276(1): 77-86. doi:10.1111/joim.12251. PubMed PMID: 24697969. https://www.ncbi.nlm.nih.gov/pubmed/24697969
6. Dubé, Catherine. “Summer: Are we well protected? Sunscreens: Saving your skin, can protecting yourself from the sun be harmful?”, Québec Science, 2006.
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