This is why journalists need to learn some basic stats. The credulity with which he takes the pro-sun researchers claims, the ignorance he displays about the shortcomings of observational studies are as depressing as they are common. Not saying, by the way, that I don’t believe the sun hypothesis, I just think this article displays false confidence. Science is hard; when you present the latest theory as The Truth, all you do is undermine long term faith in science. Sometimes these new discoveries bear out, but most of the time, they don’t. See this pattern enough and it becomes reasonable to conclude that scientists are full of shit.

Well said in many ways; however, it isn't clear that having more statistics savvy journalists would address the problems associated with media economics and incentives.

Agree. How well-trained would a journalist need to be in order to effectively analyze something that has probably taken several years of effort. Lots of numbers != good interpretations and little data != bad conclusion.

But agree with OP that in a world that is becoming less and less trusting of authority (to a dangerous extreme) that it would be nice for those in authority to have enough humility to accept when their work is questioned.

Why don't you demand as much strong evidence from the pro-sunscreen status quo?

No, because they have a demonstrable mechanism from pre-established science: UV radiation damages DNA, which causes cancer. Their product absorbs or scatters UV radiation.

This is the same as the teeth flossing skeptics: observational studies suggesting a paradox are interesting, but they actually need to unearth convincing alternative models with at least as much support as the dominant one for why they're right.

> No, because they have a demonstrable mechanism from pre-established science: UV radiation damages DNA, which causes cancer. Their product absorbs or scatters UV radiation.

As mentioned in article, but also some general knowledge in physics is that interaction of radiation with the matter is probabilistic. It is not like every quantum of UV radiation will always damage DNA, which always result in cancer. There's some "conversion funnel" that depends on a number of parameters, and the actual probability of cancer in the end could indeed be lower than probability of the negative consequences of low sun exposure. Even if physical mechanism of diseases is established, it does not mean we should always avoid the risk by disabling it by some expensive means. Sometimes it is low enough to accept it or mitigate (e.g. by efficient cancer treatment).

The article did describe some mechanisms, for instance the skin uses UV to make nitric oxide, which is known to lower blood pressure. That said, I'm not sure why this would be better than just taking nitric oxide. The same question comes up for vitamin D, and it's noted that supplements don't seem to help there -- with no explanation for that. So I would agree that the explanations for the pro-sunlight case are weaker.

   That said, I'm not sure why this would be better 
   than just taking nitric oxide

One might do well to start with the assumption that "taking XYZ orally" is not as effective as producing it naturally.

The digestive system involves a pit of acid and a diverse, poorly-understood, and variable biome. It is an extremely fraught and indirect way to introduce substances into the body. Obviously many things can be introduced this way, but the list of those that can't is probably longer than the list of things that can.

Well, I never said "orally." If it's beneficial to get NO via sunlight on your skin, it doesn't seem crazy that it might work via some lotion. Even considering oral supplements, one might also take a precursor if the molecule itself isn't stable in the stomach.

It's true there may be some important difference between sunlight-induced NO generation and whatever other supplement/injection/lotion/etc, but my point here is that the right approach is to focus on the mechanism, and avoid the naturalistic fallacy.

Surely you'd need to smear sunlight lotion on your skin if you want to use the existing the dermal route?

Not to mention that one of the premises of the article was that vitamin d levels were a marker, not some singular responsible agent.

The conclusion that vitamin D levels are an effect not a cause came from exploring the mechanisms. And yes, it may turn out that NO similarly is a marker.

It's ironic that the author didn't consider that getting sunlight may similarly be the side effect of the true cause of the stated benefits (being active?).

It may be, but NO itself is also very much a vasodilator, and used therapeutically for that.

One reason getting these from the evolved route may be better is because feedback mechanisms stop making the beneficial substance when the body has enough, which may not happen via intake by other methods. This is the case for vitamin D from sun vs oral D supplements. Serum levels stop going up when they reach a natural adequate evolutionary range if it's coming from sun. I don't know if that's true of NO or not. Or of melatonin from the near-infra-red wavelengths, but I wouldn't be surprised.

> This is the case for vitamin D from sun vs oral D supplements.

Wait, has there been a study suggesting this? This implies that there's a narrow optimal range and exceeding it causes problems. Seems you would see this in the supplement trials. Vitamin D toxicity doesn't occur until you take many times the RDA for months, and presumably none of the supplementation trials went anywhere near that high. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-h...

This feels wrong, too. You are presenting one option as a settled thing because it has a proposed mechanism.

I agree that just dropping a seemingly safe belief should take effort. I have no problem challenging them on a regular basis, though. Especially with more than just arguments and thought experiments. More observational studies can almost certainly only be a good thing.

GP didn't say that the science of sun exposure is "settled."

Also, that UV damages DNA and causes cancer isn't simply a "proposed" mechanism, it's been tested many times.

I would say pure "observation" per se has little value -- for it to be scientifically valid it needs to seek explanations.

Observational studies are certainly science. Any claim against that is going to be hard to defend.

The mechanism isn't really at question. But just as sun exposure can kill grass, so to can lack of sun. We know that humans don't do photosynthesis, but it seems reasonable to ask if we do get other benefits.

Note. Is reasonable to ask and study. Is not reasonable to just assume the conclusion.

By "observational" studies I realize you probably just meant studies where they don't manipulate a variable (which, while less than ideal, it is indeed science), whereas I was making a more philosophical point, a la Popper https://www.goodreads.com/quotes/778918-the-belief-that-scie...

Ah, makes sense. You are correct in what I was referencing. To your point, I would expect most observational studies to be done with the expection of validating understood mechanisms.

Reporters have zero incentive to accurately report on things like this.

The reporters goal is eyeballs. Job well done. By the time someone looks at it closely, nobody is talking about the article anymore.

There are other studies with interesting results in the article and it is good intuition that we survived for thousands of years stark naked without sunscreen and vitamin suplements.

One interesting paragraph was:

"When you spend much of your day treating patients with terrible melanomas, it’s natural to focus on preventing them, but you need to keep the big picture in mind. Orthopedic surgeons, after all, don’t advise their patients to avoid exercise in order to reduce the risk of knee injuries."

We need to avoid tunnel vision when making health decisions. And this coming from someone (me) who had skin cancer in the past (not that it makes me a specialist).

I don't have a horse in the race either way but

> it is good intuition that we survived for thousands of years stark naked without sunscreen and vitamin suplements

That, as an argument, is completely worthless. You don't know how those people lived, how they died, what diseases they had, all you can deduce is that some of them managed to reproduce before keeling over.

And white people that live in California or Florida should note that our complexion evolved in latitudes similar to Canada.

And if you are in the equivalent Southern latitude to Canada (e.g. New Zealand), you still sometimes need sunscreen to avoid the extra UV due to the ozone hole. Perhaps not as bad as it was, but cannot be ignored, although it is variable: https://www.rnz.co.nz/national/programmes/ourchangingworld/a...

The NZ sun is terrible. You feel the sun burning you as soon as you get outside. Burn time can be about 10 minutes on a sunny day, and maybe 20 on a cloudy day in summer.

In NZ we get about 4000 in-situ melanoma diagnosis a year. I was one of them a couple of years ago (at 37).

Wear sunscreen!

Perhaps if we are talking about the South Island of New Zealand and the southern tip of Canada (Toronto). Most of Canada would be closer to the pole.

Yeah, good point. NZ has similar latitudes down here as the USA has up there. Weather is very different since we don’t get continental effects.

Also NZ wasn’t really affected by ozone depletion, but the effects are definitely in our neighbourhood and we were worried. “While the ozone hole does not directly affect ozone concentrations over New Zealand, when it breaks up in spring it can send ‘plumes’ of ozone-depleted air towards us. This briefly decreases column ozone levels by around 5 percent, about the same amount as normal daily variation.”. Also see graph at https://niwa.co.nz/our-services/online-services/uv-ozone and notice ozone is lowest in NZ summer. Also measuring a column of ozone is most relevant in the tropics when the sun can be directly above one at noon, and less relevant when the sun doesn’t get so high above the horizon (location further towards poles, and winter versus summer). https://pubmed.ncbi.nlm.nih.gov/9671831/

For that matter, that complexion also likely evolved with clothes, and people in a sufficiently distant past may have looked quite different. The idea of people looking just like us living without clothes or shelter, presumably like some depiction of Eden, is fanciful.

I am reminded that, in addition to not going about stark naked, mesolithic humans in the British isles were dark skinned.

Also cancer takes a fair while to develop and kill you - well after age of reproduction, at which point evolutions opinion on guiding behaviour becomes much weaker.

> You don't know how those people lived

... without sunscreen.

How do you know they went out during the day and weren't completely or mostly nocturnal?

Within living memory, Americans wore hats pretty much whenever they were outside. If we decide to give up sunblock, we might want to reconsider the change in fashions that got rid of them.

That's a relatively recent phenomenon in human history as well. What about the middle ages? What about the bronze age?

Yeah... let's live like we did in the middle age. Lifetime expectancy was HUGE.

“There is a basic distinction between life expectancy and life span,” says Stanford University historian Walter Scheidel, a leading scholar of ancient Roman demography. “The life span of humans – opposed to life expectancy, which is a statistical construct – hasn’t really changed much at all, as far as I can tell.

Life expectancy is an average. If you have two children, and one dies before their first birthday but the other lives to the age of 70, their average life expectancy is 35.

That’s mathematically correct – and it certainly tells us something about the circumstances in which the children were raised. But it doesn’t give us the full picture. It also becomes especially problematic when looking at eras, or in regions, where there are high levels of infant mortality. Most of human history has been blighted by poor survival rates among children, and that continues in various countries today.”

https://www.bbc.com/future/article/20181002-how-long-did-anc...

Adjust for infant mortality, war, etc., humans are still humans.

You realize hunter-gatherers exist today, right? They go out during the day and are not mostly nocturnal. They're found all over the world.

Because it's obvious to anybody. It's also obvious that modern humans are far less exposed to UV than our ancestors, who pretty much lived like current days hobos spending most of their time on fresh air.

Our human ancestors were not nocturnal. Sleep patterns were probably different, sure, but they went out during the day to gather and hunt for food.

Sunscreen, as we know it, is barely 100 years old (see https://pubmed.ncbi.nlm.nih.gov/33583116/) and we have a lot of information up to that point.

We can also deduce from many sources that humanity did not just "managed to reproduce before keeling over".

I am actually a fan of the sun myself. I feel way better, physically and mentally, when getting decent amounts of sunlight. I would accept some risk in exchange for the benefits. But...

    it is good intuition that we survived for thousands of years 

Humans survived to the age of reproductive viability for many thousands of years.

If your goal is merely to survive until the age at which you can make a baby and rear it there are a lot of risks that can be disregarded. Skin cancer is one. So are all other cancers. No need to worry about long-term dental health either. So many fears and worries melt away. Embrace that hunter-gatherer lifestyle.

Alternatively, if you are hoping to live past your 30s (most of us would like to live at least 2.5x longer!) the lifestyles of ancient civilizations and our hunter-gatherer ancestors may not be your ticket to success.

    stark naked

This is not how people lived.

I don't buy this. Having surviving parents and grandparents confers evolutionary advantage to offspring.

    Having surviving parents and grandparents confers 
    evolutionary advantage to offspring

True but irrelevant. The reality is that lifespans were far shorter back then.

According to this page we had skin cancer for thousands of years: https://www.jaad.org/article/S0190-9622(15)00240-6/fulltext

We also completely changed our way of life. We don't live outside anymore so we have less pigment that protects us from UV.

I don’t know about stark naked - in the northern climes where the fairer complexioned folk roam(ed), furs and wool were a matter of survival.

Anyway, UV sucks, nobody is hurt by minimizing it and supplementing via diet. Hell, in the north the sun doesn’t even rise high enough to be a source of vit D for months on end. You have to get it from diet or not at all.

https://smarttan.com/news/index.php/how-to-safely-effectivel...

Look at pretty much any elder in today's tribal societies, they look like raisins at age 50. Most people would rather maintain some youthful looks which means protecting yourself from the sun.

"we survived for thousands of years stark naked without sunscreen and vitamin suplements"

We also ate differently in the Stone Age, so our vitamin intake might have been different.

Finally, life expectancy in the Stone Age was much shorter. Even excluding infant deaths, few people lived long enough to get cancer. Cancer is a typical disease of old age.

> it is good intuition that we survived for thousands of years

Well, all those people in the past are dead, so no, they did not survive.

> FTA: "it was not feasible to determine personal exposures to UV radiation and temperature"

Sadly no current consumer devices exist on market that can track these two numbers. The Microsoft Band used to have both needed sensors, but AFAIK no one else has tried to widely release a consumer product with a UV exposure sensor on it.

FWIW that sensor was a major hassle, took up a lot of space, and finding a plastic cover for it that didn't also block UV was super hard.

Couldn't you use the bleaching effect of UV to estimate exposure? It doesn't have to be an electronic UV sensor, just a spot of calibrated UV-sensitive dye.

That's similar in concept to the old style film badge dosimeters used to measure radiation exposure.

Unlike a film badge, a calibrated dye could be visually interpreted against a colour scale by the user. Neat idea if it works!

You want to avoid sunburn, while getting enough sun every day, so this wouldn't work if I understand your suggestion correctly.

There have been several wearable sensors that measure UV exposure:

https://www.wearshade.com/articles/comparison-of-wearable-uv... https://www.amazon.com/SunSprite-Wearable-Light-Tracker/dp/B...

I have the SunSprite and the June. The June is unreliable, I believe they stopped selling them years ago. The SunSprite worked well and once I'd worn it for a full year I had a good idea of my exposure at various times of year and stopped wearing it. The magnetic clasp on it sucked though, I would often find the sensor had slipped off and stuck to my car door (or anything else made of steel). Not sure if any of the sensors listed in the article are still for sale, but you can probably still find used ones on eBay.

You can also get simple wearable wristbands or tokens or cards that change color under UV exposure:

https://smile.amazon.com/gp/product/B004XMH95K https://smile.amazon.com/gp/product/B08HV91P77 https://smile.amazon.com/Fischuel-Photochromic-Indicator%EF%...

The cards are somewhat calibrated, but any of these technologies require taking into account your personal skin sensitivity.

The technology is out there, you could probably build your own sensor using an Arduino and UVA and UVB sensors. The SunSprite is cool in that it never needs charging since it charges from the Sun.

Cool, I didn't realize anyone else had productized UV sensors. I wish the tech would hit mass market devices.

> The technology is out there, you could probably build your own sensor using an Arduino and UVA and UVB sensors.

Back in 2016 or so, we were able to order UV sensors, but since there was so little knowledge about how to use them on wearable, getting them to work was a challenge.

It was months just to find a lens material that didn't block UV at all, but was also affordable, could be put on a production line, and fit all our consumer use cases (durable, chemical resistant, etc).

The cards are cool, I forgot about them.

It is unfortunate none of the main wearable players, by which I really just mean Apple, have bothered, but the UV sensor on Microsoft Band 2 was responsible for Band 2's not so friendly looking clasp, so I can't say I blame anyone for not wanting to go down that route again.

Edit: FWIW our sensor gave us something, I forget what, but I remember it wasn't what we wanted, and we had to map it to UVI. From what I vaguely recall it was one of those things where we ordered a sensor, it says it did one thing, but the thing it actually did was related but not quite the same, so we had to create a mapping curve of some type.

I came up with the user story and user flow for what we shipped, sun exposure reminders. We were really smart about it, we had logic in there to tell when you briefly went out of the sun, such as going to the bathroom, vs when you spent extended time inside, and we also worked to separate out walks to and from your car VS actually spending time outside.

To take "breaks", I believe we had an accumulator and if you went out of the sun we started a timer and if the timer went off we reset the accumulator but if you went back into the sun the timer was cancelled.

Actually starting the accumulator worked the same way, get out of car, exposure starts, if you didn't have so many minutes of continuous exposure, we never started the accumulator, an example is walking between buildings.

Lots of use case design around what ended up being a couple of dialog boxes for a reminder to put on sun screen!

Parents loved it though. :) Lots of positive feedback from parents who used it to track their family's sunscreen applications.

Edit: From shade

> 5 days of battery on a single charge

Pretty sure if we just ran the UV sensor on band our battery life would've been forever and ever. :-D

If that is a sales page, they need to list power draw of their sensor for various sampling rates, that is the only thing anyone cares about when it comes to integration.

> no current consumer devices exist on market that can track these two numbers

And if there were consumer devices, the next problem would be accuracy. Based on a bunch of reading I did several years ago (so maybe out of date), consumer excercise trackers were very innaccurate in many ways. Exercise misinformation devices.

> And if there were consumer devices, the next problem would be accuracy.

Having worked on Microsoft Band, I can tell you that accuracy is a problem with UV exposure for a number of reasons, none of which involve the sensor itself.

Mostly it is around how people wear it, and was the sensor always facing the sun, people going in and out of the shade, long sleeves, and so forth. We settled on # of minutes of high exposure, I forget what index we considered "high" but basically it if it was above a certain threshold we considered you "in the sun".

The goal was sunscreen application reminders, no way would we have trusted it to tell people they had "enough" sun!

Thanks; I am not surprised. It's hard to imagine how a sensor could be made to work cost-effectively - something that detects whatever ambient solar radiation slips through clothing? Whatever, consumers aren't going to pay for that.

But in fairness, the sensor doesn't work with how people use it. We could make a sensor that straps to user foreheads and requires them to always face the sun. When integration fails, we can point the finger either way, or just say it wasn't a good fit.

Have you looked at all the other studies, e.g. Lindqvist? [1]

[1] https://pubmed.ncbi.nlm.nih.gov/24697969/#:~:text=We%20found....

I would upvote if it wasn't for the stance of disagreeing with the implications of data that you don't have any reason not to trust.

What you describe clearly is a problem with data collection, where crucial unobservable variables had to be replaced with questionable assumptions. We should be wary because we can't fully trust those assumptions, and hence not the data, not because of what the implications would be.

Observational data is so profoundly affected by the decisions and assumptions of those who chose to select them and analyze them in a specific way that I cannot agree with this premise that the implications should be “trusted”. Those implications are a function of the choices made by the people making those decisions. The data have no opportunity to tell an independent story.

There are tools that can make this better (eg, finding an instrumental variable), but this wasn’t done here.

Global trends: https://news.ycombinator.com/item?id=31473919

To be expected from a lifestyle magazine. OO is an OK place to find your next camping destination, but it's a terrible place to look for science. This nonsense made it to HN a year or so ago.

If you're looking for sunblock that won't give you cancer or ruin the environment, check out EWG:

https://www.ewg.org/sunscreen/

Just because it isn't a scientific magazine, doesn't mean the science is junk. How exactly is it "nonsense"?

Do you have a scientific criticism of the article contents, or are you going to stick with a low-effort ad hominem attack?