I live in the tropics and there is plenty of sunshine here. So my skin doctor told me to avoid the sun at all costs, always wear suncreen and a hat, don't go out in the daytime. A few years of that and now I have a vitamin D deficiency.
Hundreds of millions live in such climates (including people with fairer skin) and have no problems, even though they don't do anything extreme like "avoid the sun at all costs, always wear suncreen and a hat, don't go out in the daytime".
I'm white and I lived near the tropics for a few years, big white and asian population, everybody was out in the sun all the time, hardly covered too. Skin cancer stats as good as Europe or US.
I’d love to know if there are any studies trying to answer my question.
Just being outside in whatever the weather consistently for 30 minutes or so every other day.
Most risk seems to come from occasional exposure to extremely strong sunlight compared to your day-to-day baseline. Practically speaking, if your skin is able to tan, absorbing as much sunlight as your environment allows for most of the year, with the intrinsic gradual build-up over spring, should be harmless if not even beneficial.
Of course, this highly depends on your genetics and your location. Avoid sunbathing around the equator regardless. And if you’re physically unable to tan, as some people do, then this might not be true either. I couldn’t determine that as easily.
https://doi.org/10.1093/ije/dyp166
It’s a decently big meta-review. It cites studies which more or less say exactly what I said very early, e.g. https://doi.org/10.1007/BF02071515
I might be completely wrong, of course. I’d rather be proven wrong than stay ignorant, so please do share the studies you had in mind.
I don't know if that means anything, it isn't n=1 sample size, it is more and my gut says it might be statistically significant.
Even though I believe that the vitamin D we can buy in bottles is probably just as good as the vitamin D my skin makes, I do not consider vitamin D supplementation an adequate replacement for getting UV light on my skin and in my eyes because vitamin D production is only one of the benefits of getting UV light on the skin and in the eyes. (BTW I think HN put way too much emphasis on vitamin D.)
There are UV light receptors (that use a compound called neuropsin to sense the UV light) on the skin and in the parts of the brain that receive UV light (which gets into the skull mainly through the eyes). These receptors have nothing to do with vitamin D. Getting UV light onto these receptors is a more potent trigger for the release of endorphins in the brain than exercise is.
Regular UV light exposure also increases levels of sex hormones in men and in women. In men, increasing testosterone increases optimism and motivation and drive. Again, IIUC this effect has nothing to do with vitamin D.
When people eat plants, the compounds (e.g., lutein, zeaxanthin and lycopene) that plants use to protect themselves from UV light and blue light tend to be absorbed and to end up in high concentrations in the retina. If you do what I do, namely, get UV light from the sun every other day in moderate doses, then I suggest making sure you are getting plenty of these compounds. (Alexis Cowan says that omega 3 is helpful here, too.)
Andrew Huberman peddles nothing more than pop-science supplement grift. I highly recommend you get your health info from somewhere other than bro-optimization podcasts and "light therapy" hucksters.
Citation needed
Calling it overblown, is... A dangerous sentiment.
We tore a hole in our atmosphere. This is not the natural way of things, no. But we do have to live with the consequences.
But considering it affects everyone, its not something to ignore - especially in a region that is already 10% more UV intense than most of the world.
There is some global thinning, but it's minor. If you don't live literally at the south pole where the actual hole is, it's not a huge change compared to most other sources of skin cancer risk.
Legend has it why Aussies call the English Poms, short for pomegranate, because they come over and get burnt to shit, end up bright red.
I love Aussies’ sense of humour!
Skin cancer is no joke, but I don’t wear much sunscreen because I don’t need to. I need all the vitamin D I can get. I wish I would’ve protected myself more earlier in life, though.
And yet mostly living in Australia, (was only in the grey UK from 2.5 years in our 20's), I'm still vitamin D deficient, because the majority of my life I've been inside on computers, presumably like a large percentage of Hacker News readers.
Ironically, our suncream QA is crap and all of the supposedly good sunscreens with high SPF factors failed indepdent testing - even including the one recommended by the Cancer Council.
Burnt to a crisp, I emails them and never heard back, I can't image I was the only person to notice.
Which is why Im probably vitD deficient too, the sun is toobharde to spend any amount of time outside unprotected here.
It's now slip, slop, slap, seek, slide - shade and sunglasses!
I'm also in the same boat but more out of laziness and hating being greasy.
Definitely wish I'd been more sun smart when younger though.
Many years ago I read that it's POME: Prisoner of Mother England, now shortened to just "pom."
You can’t say somone is being over cautious without k owing their location. It’s easier to supplement vitamin D than cure skin cancer. If the local population looks different to you there is reason to pause.
Secondly Asian people, East and South, are sun adapted. East Asians may not be dark but they, like Northern Europeans, selects for their current appearance based on environment. Just because they are not brown does not mean they aren’t sun adapted for their locale in ways visitors are not.
That and the other half of the problem is we are all sedentary as hell in all latitudes these days. Be it people hiding under AC at the tropics or hiding in heated homes in the north. We don't go outside to get enough sunlight and our fat reserves that store vitamin d don't grow large enough because we still don't go outside when the weather is tolerable.
Vitamin D deficiency might affect how well you do in school though and skin color affects that a lot. People who don't live in their native environment get such issues, just like white people getting burnt easily if they move south.
This seems obvious but was not confirmed by genetic evidence. The rate of adaptation turns out to be much higher than can be explained by skin cancer.
The real cause appears to be fertility. UV radiation breaks down folate (vitamin B9) in the bloodstream, and folate is critical for DNA synthesis and repair. Folate deficiency causes serious problems in pregnancy, neural tube defects like spina bifida, and may impair sperm production. So darker skin in high-UV equatorial regions likely evolved partly to protect reproductive capacity.
In the other direction, lower melanin production helps with vitamin D synthesis in lower sunlight environments. Vitamin D requires UV-B radiation to be synthesized in the skin, and melanin inhibits this. Vitamin D is also linked to fertility. It's involved in sex hormone production and has been associated with successful implantation and pregnancy outcomes.
If you're curious, check out Nina Jablonski and George Chaplin's work. Their hypothesis is that skin color evolution as fundamentally about reproductive fitness: dark enough to protect folate, light enough to synthesize vitamin D. Both nutrients affect fertility, fetal development, and offspring survival. They have an immediate primary impact on fertility and success, while skin cancer even in the most extreme environment/phenotype mismatch, has an onset after reproductive age.
I'm sure there's tons more cases that we don't even know about, not in the conspiracy sense, but more in the sense that there's some issues with how carefully these claims are validated before they get put out there as a rule to be followed.
> How many errors do police make? Actuaries? Security researchers?
They make plenty of mistakes too. What's your point?
I don't think I've ever seen the 20mcg rec, everywhere I've seen was something like 2000 (and that's what the supplements come as), but P appears correct.
What was the math error that led to this? And I'm curious now how to get 8000 IU. Just take a bunch of pills all at once in the morning?
The paper referenced Finland, which seems like a strong confirmation of safety, but the best information I could find was https://www.ruokavirasto.fi/en/foodstuffs/healthy-diet/natio... . What effective IU dose are people getting in Finland with these changes?
The 20mcg rec (the wrong rec) is quite literally on every single nutrition label in America that has Vitamin D. Maybe you haven’t noticed it. Surely you’ve seen it if you’re in the U.S.
https://www.fda.gov/food/nutrition-facts-label/daily-value-n...
> What was the math error that led to this? And I'm curious now how to get 8000 IU. Just take a bunch of pills all at once in the morning?
Read the paper I posted. And it is easy to find 5000iu and 10000iu capsules at a drug store.
Not in Canada!
If everyone is being told to get 10x less vitamin d than they really need, seems easy
Vit d deficiency is a known problem because of our indoor lives and sunscreen culture, so FDA requires by law supplementation of foods. Like milk. But because the RDA is wrong, these foods get supplemented with insufficient amounts.
Case in point, seasonally adjusted the typical American gets in a day average ~1800iu from the sun and ~200iu from supplemented dietary intake (2000iu total, deficient). If we were to acknowledge the RDA is wrong then milk etc could have 30x more supplementation bringing the average up and filling the gap better
https://www.nytimes.com/2022/07/27/health/vitamin-d-bone-fra...
For others. It depends.
Native South Americans, Africans and Indians seem to get skin cancer at much lower rates.
- don't stay out in the sun too long, if you do, apply sunscreen
- 10-15 minutes of sunlight exposure a day is completely fine
Stopped taking vit d and k2 it resolved after a week no problems almost a year later.
There's Vitamin K1 and Vitamin K2. Vitamin K2 is frequently taken alongside Vitamin D.
Biggest takeaway is it’s easy to hit toxic levels when taking supplements so be careful.
I am 50. I had to have skin cancer removed from my face. I have never seen a more busy doctors office than this dermatologist's office. They were printing money. The waiting room was always full, half filled with men in their 50s up (so probably not getting cosmetic dermatology surgery). Some had noses/ears missing. Granted I grew up surfing in Santa Cruz. But don't think 'skin cancer isn't a thing'.
And the follow up discussion here. Do people here not have parents? Do you not talk to ANYONE over 50 about their lives? Skin cancer is actually real and common and scary AF.