Hacker News Reader

I personally am skeptical of the idea that sunscreens are actually responsible for marine ecosystem changes, rather than climate change or other large forces

I would've said so, too, before my GF got into the reef tank hobby. Corals are ridiculously sensitive to pretty much everything. Light, chemicals, nutrients, water flow, diurnal rhythms, you name it. It's fairly believable that something in the low parts per billion might affect them adversely, particularly organisms that are already stressed.

We lost several hundred dollars worth of coral and fish in our reef aquarium when a house guest, after being told explicitly not to, used body spray stuffs two or three rooms over in a large house. These things are _sensitive_.

I have to ask: How did you trace cause to effect and eliminate other possible culprits?

It has happened before when our kids were younger and discovered perfume. These things don't mix well with reef aquariums. The rule stands at our house: no spraying anything that you are not 100% sure is reef-safe safe to spray.

> Sunscreens are really valuable technology

But is there anything functionally wrong with zinc oxide sunscreen? If not, why is it not available as the default option with chemical sunscreens available for those who want to go out of their way to not look pale?

Titanium dioxide appears to be just as good as zinc.

That’s a good point. I think tolerability is the only drawback, otherwise zinc is functionally superior because it doesn’t get depleted in the way that chemical filters do. It does tend to be a lot heavier and greasier, though, and I’d say most people aren’t okay with the white/blue cast if they’re not at the beach. So chemical filters have an important role to play in terms of making sunscreen something that people can use consistently.

I am confused. the situation is exactly as you describe, modulo the word "default": zinc oxide sunscreens are available, chemical sunscreens are also available. And I'm not sure what "default" means in this context.

Anyway, if you spend a lot of time in the sun or at the beach the functional problem with zinc oxide is pretty clear: it's harder to spread and put on. This might not seem like an issue but if you spend a lot of time dealing with it, the annoyance adds up.

Chemical sunscreens are absolutely dwarfed in terms of magnitude to oil, farm run-off and mining and industry damage/chemicals, at least here in Queensland.

This article has come up before and might interest you. [1]

tl;dr: exposure to sunlight without sunscreen has benefits for cardiovascular health - and the kinds of cancer you get from direct exposure to sunlight on a regular basis (basal cell and squamous cell carcinomas) are almost never fatal. The benefits to CV health significantly outweigh the increased risk of these carcinomas.

Melanomas only account for 1-3% of skin cancers and are less likely in outdoor workers and tanned people than they are in indoor workers.

> “The risk factor for melanoma appears to be intermittent sunshine and sunburn, especially when you’re young,” says Weller. “But there’s evidence that long-term sun exposure associates with less melanoma.”

Makes sense, humans probably wouldn't have made it this far without going outside.

[1] https://www.outsideonline.com/health/wellness/sunscreen-sun-...

Without sunscreen I burn in just a few minutes and have painful skin for the next few days. I'm okay thanks, I'll keep using it.

Resistance to sunburn increases exponentially with regular exposure, and without it falls back to your genetic base level. That's not hyperbole, UV treatment in medical facilities have to start with seconds of treatment which is increased by a percentage each time until you get to effective levels.

That's not to recommend that you try doing that yourself, just a weird fact I learned. its hard to calibrate sun exposure. But theoretically starting from very sensitive skin isn't a barrier.

And UV damage is cumulative as well. Even if you ignore melanoma, there are several non-cancerous or pre-cancerous skin conditions from sun exposure.

If you go to Asia where most women avoid any sun exposure at all (up to wearing masks and gloves) you’ll note there skin looks amazing even into their 50’s.

And the few minutes of exposure you get each day is usually enough to provide vitamin D. I think it’s like 12 min of upper body exposure in moderately intense sunlight is enough.

The point the article makes is that it's not just about vitamin D but also nitric oxide synthesized which lower blood pressure and improve CV health in excess of whatever risk you accrue from the sun exposure.

It's important to consider of course that different races age differently. Is it masks and gloves, or is it being of the local ethnicity? Not getting any sun at all is really bad, after all, since as the article shows, vitamin D supplementation is quite ineffective.

> If you go to Asia where most women avoid any sun exposure at all (up to wearing masks and gloves) you’ll note there skin looks amazing even into their 50’s.

I kind of resent the idea that this is model to strive for. Ok, you look somewhat better, but you also pay price of constantly limiting activities and having to be careful what you do ... all the time.

I didn’t read it being cited here so much as a model to strive for, but rather as strong evidence that there is UV damage to skin even at a sub-cancerous level.

Exactly. I don’t avoid the sun to that extent, but it’s pretty obvious that every strong sun exposure is a little bit more damage each time.

There was an interesting paper that show a woman who applied a sun protecting lotion to her face everyday for the last 30 years of her life.

But she didn’t apply it to her neck. The difference is very stark at 70 years old. The skin on her face was wrinkled but her neck look absolutely worse in terms of age and skin damage.

It avoiding that "damage" worth the daily effort described above? Does that damage consists of anything more then just "her skin is slightly less flat in the old age"?

That's kind of a personal choice, no?

But I think people really underestimate the impact of sun damage, particular if your skin is quite pale.

https://www.yalemedicine.org/conditions/sun-damage

Also, you don’t have to go to those extreme lengths to prevent the bulk of photoaging. Just staying out of the sun during peak UV hours and consistently using sunscreen on the areas that get the most exposure (face, neck, hands) will get you very far.

“ constantly limiting activities and having to be careful what you do ... all the time.”

This is considered a virtue among traditional Asian women.

UV damage is not really cumulative. Most of it gets repaired.

https://pubs.rsc.org/en/content/articlelanding/2002/pp/b2012...

Vitamin D production is highly dependent on time of day and latitude. At latitudes closer to the poles, even extended sun exposure might not stimulate much vitamin D. You can find online calculators which show this for your location.

That's purely DNA damage and yeah, it's "most". But not all. So it is cumulative over time.

I mean, it's pretty clear that sun exposure damages the skin. And it's not just skin cancer but other pre-cancerous changes and just premature aging.

https://www.msdmanuals.com/home/skin-disorders/sunlight-and-...

Again basal cell and squamous cell carcinomas have roughly a 100% 5-year survival rate - so much so it's not really been calculated. But the risk of melanoma, which is the bad one (and only accounts for 1-3% of skin cancers), goes down with more exposure to the sun. And as the article says, the benefits to CV health and reduction in melanoma risk outweigh the risk associated with these very low-risk cancers.

That article isn't strictly wrong to say that exposure to sunlight is linked with melanoma, but it's linked to childhood sunburns and intermittent sunshine/sunburn. Sunburns are bad, sun is good.

> And perplexingly, outdoor workers have half the melanoma rate of indoor workers. Tanned people have lower rates in general.

I think it's also fair to say that exposure to the sun doesn't cause premature aging so much as not being exposed to the sun makes you look younger than you would otherwise - but of course that only helps if you're alive. Direct sun exposure reduces all-cause mortality. [1]

[1] https://onlinelibrary.wiley.com/doi/10.1111/joim.12251

Interesting article, but note that moderate sun exposure has a lower mortality than either "no" or "lots of" sun exposure.

Which is not surprising considering the need for sun exposure for things like vitamin D.

But I'm not sure mortality is the best measure? Maybe quality of life? Getting surgery to remove a basal cell carcinoma and having failed skin grafts (happened to my grandmother) seems like a heavy burden to cost of life not captured in mortality.

I’ve not much to add other than to say I’m sorry to hear about your grandmother! Hope she pulled through ok.

Upvoted for the kindness. Appreciate it.

There's no point in talking about sunscreen without reference to skin type. You're probably a Type 1, which doesn't tan in any significant way.

Anyone in the 2 and 3 range can build significant sun tolerance by being careful, 4 and 5s don't generally need sunscreen. Jury is out on skin cancer, Bantu people in Africa don't all die of melanoma, so clearly melanin is doing a lot of work here.

Just use reef-safe sunscreen... and help- protect what makes Hawaii & the tropics amazing https://www.popsci.com/gear/best-reef-safe-sunscreens/ This has been well known in the dive community for a while, the NEWs here is that beach-bodies need to use reef-safe sunscreen too.

This shouldn't be down voted. Regular sun exposure is correlated with lower all-cause mortality.

https://onlinelibrary.wiley.com/doi/10.1111/joim.12251

It reduces blood pressure.

https://www.nature.com/articles/s41598-017-11567-5

Yep, that's exactly what the article I linked says too haha.

Folks out here worried about how wrinkly their skin might look at 75 when nobody cares instead of cardiovascular health though :)

I think instead of bending the knee to the idea of fatigue, it’s more important to accept that humans really are screwing up things on a massive scale faster than ever. Plastic straws, chemical sunscreens, gasoline, etc are all very recent inventions. It’s not unreasonable to look at massive unprecedented changes in the world and conclude that some of these things that came into widespread existence within recents decades is also causing massive destruction that only began in recent decades.

Completely disagree. Fatigue isn’t just an “idea,” it’s an unavoidable consequence of repeated exposure to a stimulus.

The political will to solve problems is a finite resource. Squandering it on trivial crusades is, IMO, one of the most wasteful and harmful decisions that could be made.

> The political will to solve problems is a finite resource.

Gee, humanity had better act fast to protect that precious finite resource. What would our children and grandchildren think if we squandered our political will to solve problems?

I imagine they’ll think that the problems went unsolved?

Less finite than earth’s natural resources amidst the unprecedented rapid deterioration and destruction of basically everything on earth sans colossal asteroid strikes?

Trivial to some upper class person in an air conditioned home who doesn’t want to think about bad things and who’ll survive no matter what is certainly not trivial to billions increasingly struggling to survive with no way to escape to greener pastures.

The upper classes are more likely to support environmental policies, so this is a pretty asinine comment. And it's these same upper classes that are pushing for frivolous as opposed to substantive policies (plastic straws, anti-nuclear, etc).

https://www.researchgate.net/publication/325157337_Social_cl...

Yes, if you are trying to change human beliefs and attitudes, you can't disregard human nature or behavioral psychology. Duh.