Does Sunlight Really Cause Skin Cancer?

May 6, 2022

Anybody who understands the basic concepts of ecosystem and biology knows that the Sun is the fundamental life force for life on Earth. The ancient Egyptians worshipped the Sun as their God(the Sun God, Ra) which was very apt in my opinion. We, as a species, have lived and played under the Sun for centuries since the dawn of mankind. So the idea, that it causes cancer, a modern-day disease is immediately absurd and ridiculous. The rates of cancer have risen astronomically since modernization, and not surprisingly because it is well documented that the most common causes behind this disease are creations and practices that involve unnatural alterations to our environment. Something that has been rampant with industrialization. So where does this idea- that the primary cause behind skin cancer is sunlight- come from? 

I would guess it comes from the same place that espoused the ideas that red meat causes heart disease; that the main cause of most illness is viruses and bacteria. Or our genetics. Corrupted science. I don’t want to digress and go down this (very massive)rabbit hole. Let’s just say it is not uncommon for industrial interests to influence science to protect their questionable practices(“Follow the money”). And resultantly shift the blame for environmental and health issues that they might be causing, on natural causes.

I say “I would guess” but that's not what we want to do here, right? So let's put our prejudices away and keep an open mind. And, briefly take a sincere look at all of the evidence and history surrounding this claim:

Skin cancer is the most common form of cancer, accounting for 40 per cent of all cancer cases. Skin cancer kills around 80,000 people a year.

The 3 main types of skin cancer are-  basal cell carcinoma, squamous cell carcinoma and melanoma. Of these, the first two are broadly categorized together as non-melanoma skin cancers. These are much more prevalent and usually don’t become serious. Most cases are easily removed and don’t even get added to official records. Melanoma, on the other hand, while accounting for only 1% of cases, is responsible for the majority of deaths from skin cancer. This is the type of skin cancer that actually matters.

The good news? it is now widely accepted that while sunlight may be causing the less serious non-melanoma cancers, it most likely does not cause melanoma.

This is a fairly recent development that happened in the last decade or so following mounting clinical evidence of melanoma cases in parts of the body that didn’t receive any sun exposure. To the point where it became so irrefutable, it is now stated in mainstream medical fact sheets on skin cancer. But as is the case with a lot of things, the old paradigm continues. Paradigm shifts are always difficult in science, especially in cases such as these where the money works against it.

Melanoma cases have risen 3000% since 1970. And we spend a lot less time outdoors than we did in the 70s. Most of us are inside on our computers now and the kids are playing video games. Doesn’t add up, right?

Sunscreens were introduced in the 1970s as well, and the rate of melanoma has only increased with the increase in sunscreen use. So is it the sunscreens that are causing melanoma? Well, we do definitely have some data on mechanisms supporting direct causation. Firstly, it’s been shown that a lot of ingredients in sunscreens are carcinogenic, to varying degrees. And the other point to note is that the initial generations of sunscreens blocked only the UVB rays while melanoma was found to be caused by UVA. The filtering out of UVA rays is said to have possibly aggravated it. Almost all commercial sunscreens are very bad for your health in general, though. More on sunscreens later.

Coming to the main causes of skin cancer cited by official sources as of today. The primary identified cause continues to be UV radiation, from the Sun and other artificial sources such as tanning beds(this is despite them stating, usually on the same page even, that melanoma, the most important form of skin cancer is probably not caused by UV radiation). And resultantly, prevention measures cited in health guidelines are almost all centred around reducing sun exposure- such as wearing hats, full covered clothing in the Sun, not going out during peak daylight, using sunscreen etc. As I said, it’s a whole paradigm and thus hard to change.

Other secondary causes or “risk factors” that are cited include- being fair-skinned, having a weakened immune system, family history of skin cancer and genetics. These are all very valid factors, I think. Skin colour is definitely a huge factor. Caucasian people are estimated to be at risk of skin cancer around 15 times higher than people of colour. This is why skin cancer is a much bigger health concern in white populations but we don’t hear much about it here in India.

Skin Cancer, like any other cancer, involves an uncontrolled growth of cells. This can happen in any part of the skin, and in serious cases, spreads to other parts. This is said to be caused by a DNA mutation. And the claim is that UV radiation is the primary cause behind this mutation. 

So how good is the data behind this claim? There is a vast amount of literature on this. It's one of those topics that are very controversial and have a large number of papers on them.  None of the data here is very conclusive though. Most of the data involving human subjects is epidemiological. The few clinical experiments that do exist, involve animal studies with artificial UV radiation, often filtering out specific wavelength bands to deduce their effects separately. Apart from these, there are papers that attempt to show the mechanisms that are theorized to be involved in the process of UV light causing DNA damage and leading to skin cancer. These papers might provide valuable insights of their own, but using them to assert that sunlight is the primary cause of skin cancer, based on isolated mechanisms is not sound.

Some of the papers reviewing the data on UV radiation and skin cancer also propose to address the question posed at the head of this article- how is sunlight, which we have had all through our evolution, be causing this modern-day disease? And their answer is something most of us studied in high school- ozone layer depletion. They cite data that allegedly shows that these chemicals, CFCs and HFCs, which are emitted mainly by air conditioners, refrigerators and aerosol cans, have been depleting the ozone layer. Due to this, more UV radiation reaches us now than it did earlier.

Personally, I definitely don’t think that the sunlight and skin cancer link is a complete myth. Sunlight is a notable factor in causation. But it’s not the culprit or the primary cause. And I most definitely do not think we should be avoiding the Sun. Most of us today need to be getting a lot more sunlight, when all health factors together and not just skin cancer risk are considered. This is a very common practice in modern mainstream medicine- to focus on isolated mechanisms for formulating health guidelines, while completely ignoring other effects. That is why the alternative healthcare industry is so big on being “holistic”, you must’ve noticed.

Being out in the Sun has a vast array of positive health effects. It creates Vitamin D of course. But the health benefits of full-spectrum white light during the daytime is hugely understated. It boosts your serotonin and cortisol, among other things. It very strongly affects your neurotransmitter and hormone levels positively and corrects your circadian rhythm. This happens not just through your eyes, but even your skin cells which can read light and trigger biochemical reaction chains. Sunlight is a natural antidepressant.

Sunlight Effects on Human Body

The research on sunlight and cancer(all kinds not just skin) is also very interesting:

“Several recent studies suggest a possible inverse relationship between ultraviolet radiation exposure and risk of non-Hodgkin lymphoma, colon, breast and prostate cancer, and investigators have speculated that this might be due to the higher serum levels of vitamin D stimulated by high lifetime sun exposure. Further, studies conducted within cohorts using stored pre-diagnostic serum suggest that those with high levels of vitamin D have lower incidence rates of a number of malignancies, particularly colon cancer.”

This is from the same paper CDIC paper reviewing the data on sunlight and skin cancer that is cited in multiple mainstream health outlets as evidence for stating that sunlight causes skin cancer. Indeed, Vitamin D is highly anti-cancer. This is why it is important to consider the holistic effect instead of just the DNA-damaging mechanism. Sunscreens block vitamin D too, by the way. This is disputed in some studies but I think it’s safe to say that it does happen to some extent, at least. Most likely to a very significant extent.

Sunlight is a stressor. It creates oxidative stress in our bodies. This is why I say it is a factor in skin cancer causation. But it’s not the primary cause. Natural stressors are a part of our life. But the exposure to them should be in moderation. You probably know about hormetic stressors like fasting and ice baths which are very popular practices in the health space today. In moderation, in the correct quantities, they are very beneficial. But overdo them, and you will get sick. The natural signal to tell when you’re overdoing your sunbath is pretty clear- sunburn. Sunburn is most definitely bad for your skin. And that’s what the research saying UV radiation causes skin cancer also says- that it is the sunburn specifically that greatly amplifies your risk. Sunburn is when the oxidation caused by sunlight in your skin has overrun your body’s capacity.

The correct way to get sunlight is to gradually increase your exposure so you develop a tan that protects you. Melanin is your skin’s natural protector from Sun damage.

I said I don’t think sunlight is the culprit behind skin cancer. So then what is? Of course, it doesn’t need to be a single thing, and in most cases in health etiology, it is multiple factors. But the single biggest cause that I can point to for skin cancer would be diet. There are a couple of specific things in our diet that are particularly important for skin cancer. The first is eating a high antioxidant diet. There is a lot of data showing high antioxidant content in the diet reduces skin cancer risk significantly. The reason behind that is obvious. Since antioxidants help counter oxidative stress.

The second thing is cutting out industrially refined seed oils like soybean, canola, sunflower, rapeseed etc. And switching to healthier natural fats, particularly saturated fats. Thus improving your omega-6/omega-3 ratio. There isn’t much data in the literature on refined seed oils and skin cancer specifically. But the anecdotal evidence here is staggering. If you’re active in the carnivore/low-carb diet space, you’ve probably heard about this. People quit their consumption of these refined oils and experience a drastic drop in sunburning almost instantly. Apart from this, there is a lot of evidence linking these refined oils to cancers in general though. They’re plain carcinogenic.

Of course, even just beyond these two points eating a healthy and more unprocessed diet, in general, is very important too. For a comprehensive review on diet and skin cancer and all that you can do with your diet to minimize skin cancer risk, do check out this excellent article from Mark Sisson, linked below.

The biggest issue with the public health messaging on skin cancer, though, is the recommendation to use sunscreens. That too multiple times a day, since guidelines often ask to re-apply every 2 or 4 hours. This is just flat out health misinformation that harms your health. Mainly because of how bad the average sunscreen product in the market today is.

I already talked a little bit about sunscreens and skin cancer above. But even apart from that, there are a lot of issues with the chemical ingredients and preservatives in sunscreens. They have been shown to cause endocrine disruption and developmental and reproductive disorders. One of the commonly used ingredients is highly anti-testosterone. Of course, effects vary based on the particular product and the ingredients used.  I won’t go into details of that.

Another negative aspect of some sunscreens is that while they do block the part of the sunlight that causes sunburn, they don’t stop all of the aggressive rays. What ends up happening is this blocks the natural sunburn from happening that acts as a  signal for us to get out of the Sun. So people often stay in the Sun for much longer, unaware that they’re getting skin damage.

Sunscreens have caused massive damage to the coral reefs and marine life too. Because the chemicals wash off from people’s bodies into the water. Thailand banned the use of sunscreen last year for this reason. I’m no expert but I can only imagine how toxic these sunscreens might be if they’re straight-up destroying marine life like this.

The following are quotes from Dr Elizabeth Plourde, who has authored multiple books on the hazards of sunscreens after researching them almost lifelong. From her interview with the Weston A. Price Foundation:

“I’m very grateful as I learnt to scuba dive 50 years ago and got to see the gorgeous corals. It is just breathtaking down there. In fact, I have to remember to keep my mouth shut because it opens up in such awe of gorgeous..all the different animals. And then I got to see them dying. I got to see a beautiful expanse of coral in 1980, where the cruise ship was saying to all the thousands of people unloading every day- ‘put on your sunscreen, put on your sunscreen’. And when I went back in 1985, the entire expanse was totally white..”

“..the chemicals in the sunscreen as well as the preservatives in the sunscreen can kill the corals in 96 hours to the point of being bleached white. And then as I kept investigating what these chemicals do, I became horrified at how toxic they are to all of us..”

“..It’s a multibillion-dollar industry. So they’re not going to give it up easily and they're going to fight it. And these fights in the medical journals of these doctors who said their experiments proved that there was no protection from melanoma and no protection from basal cell carcinoma..they were just ostracized in the journals. But then when you track down who was funding the doctors who were ostracizing them..they were funded by the cosmetic companies and pharmaceutical companies that make the sunscreen”

Same story every time.

So should you never use sunscreens then? I think most people don’t need them in their daily lives. But there could be situations where someone is at high risk of sunburn. Like if you need to be in the Sun for a long duration someday for some reason and especially if you’re light-skinned. But you definitely don’t want the commercial sunscreens. The safest kind is zinc oxide creams with large particles(not nanoparticles which some products have because they can seep into the skin). Check out this article by Chris Kresser(linked below)  for product recommendations. Also Dr Saladino(“Carnivore MD”) has said his team is working on launching a zinc oxide sunscreen with saturated fat only. Since refined seed oils are another issue with sunscreens and commercial lotions. They absorb and seep into your skin and bloodstream as well.

To conclude, I’d just like to say that, yeah, the data might be complicated. But just look around you. How many people have serious skin cancer? And how many people have low vitamin D and/or depression?


Ranodeep Seth
Content Writer

An IT graduate, Ranodeep has worked in IT operations and as a tech blog writer in the past. He is very passionate about health, owing partly to his own chronic health issues which plunged him much deeper into the field. He works for iThrive both as a writer and in the software design team. He is a strong advocate for “informed consent” in healthcare and aims to promulgate the same through his work.

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