281–290 of 308 posts
Vitamin D is a biomarker of a process that happens in the body that is beneficial for longevity. This biomarker is created in response to receiving sunlight. The synthetic vitamin itself, does little, if anything, for your health. The process of receiving the sunlight is what benefits your health. This applies to a lot of other vitamin supplements as well. So whilst you may be able to take a supplement to boost your…
I have made this comment on HN many times [0] now but: it's the goddamn sunlight. Sunlight has many pathways in the body, and increased vitamin D levels are just one of those pathways. Swallowing one element of a many-element pathway cannot simulate the human synthesis of vitamin D! This should be obvious! Your car might not run because of bad needle bearings, but the solution is not to add them to the gas tank! Firs…
Here in northern Europe, there just isn't enough sunlight to not become deficient, so a vitamin D supplement is a must.
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Have you looked into UVB lamps?
Had a friend talking about them, but they seem to be prohibitively expensive. Do you have positive experience using such lamps? I tend to have some eczema on my scalp that sun really helps with. Maybe a lamp that costs the equivalent of a week of holidays in a warm place could be justified after all.
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Is it really less intense? When I go out on a sunny day in Denmark it is murder. When I go out on a sunny day in Italy it's generally just overall warm. At any rate another factor is that in the Northern regions it's my experience people do their best to soak up as much sun as possible.
I could believe that if you were near the coast. I grew up in central Michigan and thought the same about the sun until I spent a few years in southern Arizona. The sun there feels like a heat lamp in summer. The low humidity makes the atmosphere absorb less energy. Although it feels like it's about 5 C cooler than it actually is because sweat evaporates so quickly, but once it gets to 43 C you actually just feel vag…
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> The reason for this is that the sun is at a low angle, so it hits more of your body than it does when the sun is overhead - like you'd get in Australia. This also means that while you need some sunscreen during the day - from about 10 to 5 - it doesn't burn as much. Not sure if I parse this correctly - I'd imagine you need more sunscreen at "low angles" due to more severe and longer exposure? Low angle -> more body…
No, because the sun at low angles passes so much atmosphere, that filters most out. The exposure angle of your body also has a effect, but much weaker.
(Yet I can feel that I got slight sunburn being out for about 15 minutes today. So you still need to be careful.)
In winter the UV index might often peak at 1-2 on a clear day.
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Come to Australia during the summer and watch how quickly you burn outside without sunscreen.
Only for fair skinned individuals
I have made this comment on HN many times [0] now but: it's the goddamn sunlight. Sunlight has many pathways in the body, and increased vitamin D levels are just one of those pathways. Swallowing one element of a many-element pathway cannot simulate the human synthesis of vitamin D! This should be obvious! Your car might not run because of bad needle bearings, but the solution is not to add them to the gas tank! Firs…
We really need to drill down into ethnic and racial boundaries to really make sense of how much sun exposure helps us.
Early into the Covid pandemic, there was talk that vitamin D had some protective effect. Did this ever pan out into any kind of recommendation supported by evidence ?
Vitamin D is a biomarker of a process that happens in the body that is beneficial for longevity. This biomarker is created in response to receiving sunlight. The synthetic vitamin itself, does little, if anything, for your health. The process of receiving the sunlight is what benefits your health. This applies to a lot of other vitamin supplements as well. So whilst you may be able to take a supplement to boost your…
Do you have any sources for this? Genuinely interested in reading more.
I feel bad for posting this without references so here's one reference I could find right now:
> This study shows that longer wavelengths in sunlight are transmitted through the body. When these are presented via NIR LEDs in a laboratory-controlled environment at much lower energies, they again have the ability to be transmitted through the body and also are associated with improved visual function independent of ocular exposure. Hence, body penetration by longer wavelengths impacts systemically. Longer wavelengths improve mitochondrial membrane potential and ATP production and improve function in a species conserved pattern that can impact on mobility, visual function and cognition, particularly in ageing. In short lived animals they can extend average life span.
> Taken together, these data provide evidence of the importance of the full spectrum of sunlight for human health. They also highlight the potential dangers of the restricted spectra found in white LED lighting in the modern built environment that lacks longer wavelengths and whose output is generally restricted to around 400–650 nm. The absence of longer wavelengths from LED light sources may have implications for public health that should be addressed.
Source: https://www.nature.com/articles/s41598-025-09785-3#Sec5