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Also in the Pacific Northwest - a doctor once told me that at our latitude, the sun never gets high enough in the sky for humans to be able to rely on sun exposure alone to meet our needed Vitamin D levels.

And this article is about Finland. Seattle is 47N LAT, Helsinki is 60N. That's around how far north Whitehorse is in the Yukon - very little Vitamin D is possible from sun exposure that far north.

Yep, around here it's mostly the early afternoon hours during summer months that the UV levels even rise above the threshold of triggering cholecalciferol synthesis. For many people the summer vacation is pretty much the only time of the year that they have a chance to synthetize vitamin D on their own.

I spend a fair percentage of my recreation time outside in California and as far as I can tell, if you work indoors and wear sunscreen outdoors it's probably hard to get enough vitamin D from the sun, anywhere.

Contrary to that, I've read that in the south of Britain, so say 51°N, just 15 minutes exposure in the middle of the day in the spring and summer months, on the face and hands alone, gives you sufficient vitamin D for the whole year.

* "Sufficient" ≠ Optimal

* That's for light skinned folks.

* I suspect the difference between 51°N and 56°N (ie, Scotland) in such a study would be much larger than most would think.

* From the authors: "It is important to note that this should be undertaken in the middle of the day, with exposure of lower arms and lower legs to maximise benefit."

Sufficient is enough, and yes I am aware that the difference at the other end of the country is indeed stark, the point being that southern Britain is still several degrees north of the parent post's Pacific Northwest, where it was said to be impossible.

I'm at 47°N and anecdotally, I did ~30-40 minutes walks in the midday sun this summer, with either face/hands/arms or additionally also legs exposed. At the end of summer I measured at 26mcg/l, which is barely above the "deficient" threshold of 20mcg/l and still well below the often recommended target of 50mcg/l. So I doubt that "face and hands alone" will give you "sufficient vitamin D for the whole year". Note that I was also taking 2000 IU per day in winter/spring, which I stopped taking in summer. Now after the bloodtest I've resumed the supplement for fall and upped it to 4000 IU + added Vitamin K2.

Feb 17 -> Oct 22 you can get vitamin D from the sun in the PNW, although for a chunk of that its not going to be enough to get you to 8000 IU.

Fun fact for anyone who’s never been this far north:

I grew up In Edmonton Alberta, and in the winter not only is there not much benefit from sun exposure, but: the sun does not warm you. The sun feels cold even at full-bright noon.

it depends on so many things that we probably dont fully understand though.

Each blood test I get i'm within range (pretty much right in the middle) for everything. I take zero supplements. I eat a variety of things over the course of the week, always somewhat balanced (i eat more veggies than the average american i'd say and perhaps way more fruits). I exercise, with a shirt on (lol). Sometimes for many hours, sometimes for 30min. Totals hours over the course of the week. I take zero supplements normally. I see these as an option or for specific cases rather than "the daily pill" (in fact, the "daily pill" things scare me a bit, I'd rather not rely on pills - the science don't seem clear enough and the things you can buy are definitely unclear)

Every now and then i crave specific things like orange juice (ie high vitamin C contents).

All that to say best way to know is probably to test, but also, if you go bike 20min shirtless every 3 days and walk 20min a day I assume you don't get nearly as much vitamin D as I do, so it kinda makes sense to me. But still depends on the person, how much sun, yada yada.

Clouds are translucent to the UV light needed for vitamin D synthesis. Even so the days get pretty short up north.

Also you haven’t mentioned your skin tone. Persons with darker skin will obviously have a harder time synthesizing vitamin D from sunlight. Fortunately the PNW is rich in salmon, one of the few good natural dietary sources of vitamin D, which certainly helped earlier peoples to maintain their health.

I'd say I'm about an #FFCD94 or so.

I've also started adding more salmon into my diet. A 100g serving seems to be about 500 IU of vitamin D. Apparently fat helps with absorption of vitamin D, so it seems like a good way to get it. Still, not sure it would be enough, and I'm not willing to forego the supplement this winter to see where I'd end up.

In the PNW walking in the afternoon probably wont do the trick. You should use the Dminder app and get outside at solar noon (1pm).

Sadly there is only a couple of weeks left in the PNW where you can get any useful level of vitamin D (not because of rain but because of the suns position in the sky). However if you try again next summer and get to a high level, it takes sometime to drop over winter.

>Subjectively I can say that I feel far better than I did a few months ago, but that could be placebo or due to other factors.

To add additional anecdote: I've taken dozens of different supplements and nootropics on an experimental basis over my life.

Vitamin D is the ONLY one I still take because it consistently makes me feel better.

Vitamin D is fat soluble. Outdoor-raised animals produce vitamin D and store it in their fat. Eating fatty meat from outdoor-raised animals provides vitamin D.

The trouble is most animals are not raised outdoors. You need to find a good source to get a decent price on grass fed beef/lamb.

Agreed. My opinion is that we need to eat less, higher quality meat. Don't get fried chicken for a snack, cook a pasture raised chicken roast and use the leftovers. Better for us and improves animal welfare.

This still might not provide adequate vitamin D. But I think the demonization of fat is part of the Vitamin D problem.

Fatty fish like salmon or canned sardines are a relatively expensive but easy to obtain source.

Sardines are relatively high in arsenic so best to limit your intake.

Solar "vitamin D" is a constellation of variants. I trust the body's innate biochemistry() is more healthy than the latest pop-medicine. Solar exposure is preferable over pills. Except you may get enough wearing winter clothing.

() Pale skin may be a recent evolutionary trait of some humans, less than 20,000 years old.

Which mail in vitamin D test did you use? Was just looking for something like that.

Everlywell. The test was $50 but it's easy to find coupon codes that bring it to $35. Can't speak to the accuracy of course, but otherwise it was pretty easy and I got the results quickly.

In most places only men can take walks shirtless...

Perhaps stupid question, but did you wear sunblock?