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Question about vitamin D production and sun altitude

Ocean

Senior Member
Messages
1,178
Location
U.S.
I'm trying to figure out exactly when I can no longer get vitamin D from the sun for this year. I am referencing this chart http://aa.usno.navy.mil/data/docs/AltAz.php

I read somewhere on PR that when the sun altitude is below 50, you can't make vitamin D. But using that number and the chart linked above makes "vitamin D winter" where I live start much earlier for me than mainstream sources seem to say it does. Does anyone have a link to definitive info about what altitude the sun needs to be at in order to be able to produce vitamin D from it?

(I understand the altitude of where you live also plays a part, I'm taking that into account.)
 

*GG*

senior member
Messages
6,389
Location
Concord, NH
That's the website Dr. Mercola shows at the beginning of this video:


GG

PS Hope this helps. I just take a supplement all the time, and might start doing a little tanning bed?
 

Sherlock

Boswellia for lungs and MC stabllizing
Messages
1,287
Location
k8518704 USA
I just take a supplement all the time, and might start doing a little tanning bed?
IIRC, Cannell at Vit D Council was surprised to discover that supplements did not give the same benefit in M.S. that the sun did. My opinion is that vit D is vastly overhyped. It has failed in many actual studies using outcomes as the endpoint, instead of just using markers. Still, if anybody is very low in levels, that's another story.
 

Ocean

Senior Member
Messages
1,178
Location
U.S.
That's the website Dr. Mercola shows at the beginning of this video:


GG

PS Hope this helps. I just take a supplement all the time, and might start doing a little tanning bed?
Thanks GG that's the same site I use. I just am trying to figure out what altitude of sun to look for on that chart as the end limit of when you can get vitamin D. I read it's 50 but am not sure if it's right or not.
 

Ocean

Senior Member
Messages
1,178
Location
U.S.
I think I'm not asking my question clearly maybe. On the chart I linked to you can see the sun's altitude at different times of day, on different dates, in different parts of the country. I'm trying to find out what sun altitude is too low for a person to be able to make vitamin D. So if the sun is at 50 on a certain day where I live I think I can make vitamin D during that time that it's at 50. What about when the sun is at 45 or 40 altitude, can I still make vitamin D then? What is the cutoff number for the sun's altitude for making vitamin D?

Does what I'm asking make sense? Thanks all.
 

IreneF

Senior Member
Messages
1,552
Location
San Francisco
I'm not sure how one would figure this out, since not only would you have to factor in latitude, time of year, time of day, and probably cloud cover, but also your skin tone and amount of skin you are exposing. Perhaps there is a *local* public health site you can consult. Around here there is more emphasis on sunscreen.
 

Ocean

Senior Member
Messages
1,178
Location
U.S.
I'm not sure how one would figure this out, since not only would you have to factor in latitude, time of year, time of day, and probably cloud cover, but also your skin tone and amount of skin you are exposing. Perhaps there is a *local* public health site you can consult. Around here there is more emphasis on sunscreen.

There is a formula that below a certain sun altitude it's impossible to make vitamin D from the sun for anybody, regardless of skin color or amount of skin exposed or amount of time in the sun. At that point it could be clear blue skies and you still wouldn't be able to make vitamin D. I'm just trying to figure out what that point is. I'm just going to go with 50 for now since that's the only number I've read and nothing else has been proposed, though I prefer the number to be lower so I can get vitamin D longer into the year!

I think skin color only has to do with how long you need to be out when it's possible to make vitamin D, and does not affect when in the year vitamin D can be made that is the same for everyone in a given location from what I understand. The time of day and date and all that is in the chart linked above in my original post. So the only real essential missing factor is the altitude of the sun question that I'm trying to figure out.