So you can supplement 2000IU year round without getting calcium build up? My problem with vitamin D is it's really not clear how much is safe to supplement.
There is at best modest support that shortened leucocyte telomeres cause differences in lifespan. Results of Mendelian randomization studies are weak and causality is uncertain. Some evidence that longer telomeres may increase cancer risk.
Pretty good news! But also I think this study tells us that people are infact staying in doors more then they should! Our levels of vitamin D are likely really low in general otherwise we wouldn't see that much of a diference.
I bet the supplement industry is going to be splashing this study all over the internet for the next few months.
I don't see how being in the sun could be bad for us. We've been doing it for as long as we've existed and every other form of life does it as well. Anecdotally, I feel amazing when I'm sunbathing and I feel terrible during winter when there's less sun. The only explanation I can come up with is that modern people are somehow uniquely sick so their bodies can't do what every other organism has done for billions of years.
Uv rays are not safe. But not getting uv rays is also not safe. Like so many things in biology, bodies are optimized for ranges in the middle and not at the extremes.
That's been my conclusion recently. While I'm sure it's true that people aren't getting enough vitamin D because they are indoors a lot, I'm not convinced you can't easily get enough of it in supplement form. If UV is only needed for vitamin D then you might as well avoid the aging effects of UV exposure and pop a pill.
I don't think we know the entirety of what happens in the skin with UV exposure. We are pretty sure that vitamin D is good, and that cancer is bad, and that seems to be all that people talk about, but there are a lot more things happening that we don't fully understand.
I suspect when we know more, the best answer is going to be moderation. But it's really anybody's guess right now.
There are even things that we do know about but generally aren't talked about such as UV-triggered nitric oxide release[1] which moderates blood pressure among other positive effects.
I want to be clear that there being pros and cons whose relative proportions change is very different than what some other commenters seem to be implying which is closer to a threshold model of UV safety which clearly doesn't exist and is non-scientific.
I'm aware of the importance of wearing a hat (with a brim) when in sunlight, to protect scalp and ears from UV radiation.
"Researchers think the three primary types of skin cancer -- melanoma, basal cell carcinoma, and squamous cell carcinoma -- are mostly caused by too much time in the sun. So it’s very important to use sunscreen or cover up if you’re going to be outside longer than 15 minutes or so." https://www.webmd.com/a-to-z-guides/ss/slideshow-sunlight-he...
there's nothing wrong with being in the sun. but there's no denying UV rays damage the skin, accelerating the signs of ageing- hence the recommendation by dermaotlogist to avoid it.
I'm not sure how you square that with findings that show any increase in UV exposure is associated with all-cause mortality[1]. It would seem that in this case common sense is bad sense.
This is exactly what I mean. You cite a single 12-yr old study and extrapolate its conclusion to extremes.
No mention of the Swedish cohort study (Lindqvist 2016) showing sun-avoiders had 2x mortality risk over 20 years. No mention of the dozens of ecological studies showing inverse relationships between UV and many cancers.
I could go on all day. You can't just paste one link and call it settled science.
For your consideration a 2025 meta-analysis[1] of 73 eligible articles concludes no change to current avoidance recommendations.
You'll notice that Lindqvist 2014, 2016, and 2020 are references 77, 78, and 79 respectively. Definitely interested in what evidence would change your mind. Any chance you could describe your evidentiary bar?
The meta analysis is inconclusive. I would not use that as evidence to back up the idea that you should avoid any UV exposure. I’d describe this as a complicated situation where reasonable people could disagree.
“””
What did we find?: Our findings are mixed. Exposure to sunlight has been reported both to increase and to decrease your risk of dying. Alongside its harmful effect on skin cancer, sunlight may help prevent other types of cancer. However, there were issues with the amount of data available, as well as the quality of some of the data that was available, so we can’t be certain about the findings. Currently, there is not strong enough evidence to alter sun exposure advice and so people should continue to follow the guidance.
“””
I’m not the original poster but one thing I look at is recommendations from bodies in other countries that have more experience with the issue. During COVID I found countries that had experience with SARS had better guidance than the US.
Similarly Australia has more than 2x higher skin cancer risk. The American Academy of Dermatology recommends even people with dark skin wear sunscreen daily, even if they don’t go outside. Australia doesn’t recommend this noting the tradeoffs of having higher risk of vitamin D deficiency.
