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The best comment from a vitamin D study I remember is "you can lay buck naked on a rook in January all day but won't get enough vitamin D". Referring to norther

The best comment from a vitamin D study I remember is "you can lay buck naked on a rook in January all day but won't get enough vitamin D". Referring to northern US and Canada in winter.

FollowingTheDao 3y ago
It’s insanity to me that the only route people think you should get vitamin D is from the sun. In fact, most of us Caucasian Europeans should be getting it from our diet. Cold water fish has the highest amount of vitamin D.
- deleted 3y ago
  [deleted]
- david-gpu 3y ago
  > It’s insanity to me that the only route people think you should get vitamin D is from the sun. In fact, most of us Caucasian Europeans should be getting it from our diet. The fact that the skin of your ancestors rapidly evolved to become much lighter as they migrated to more polar latitudes tells you all you need to know about whether diet was an adequate source of vitamin D. Light-skinned people are particularly well-suited to obtaining all the vitamin D they need from sunlight alone. It is dark-skinned people currently living far from the equator who benefit the most from vitamin D supplementation, because the melanin in their skin reduces their ability to synthesize vitamin D from the meager amount of sunlight they get.
  - ffhhttt 3y ago
    It wasn’t very rapid. In most of Europe white skin was introduced by famers migrating from the middle east who displaced the hunter gatherer populations at the beginning of the neolithic.
    - david-gpu 3y ago
      Thousands of years is the blink of an eye in evolutionary terms.
      - ffhhttt 3y ago
        Maybe, but my point is that it initially appeared in the middle east (and probably in northern Eurasia at a similar time) but was likely first introduced throughout most of Europe by migrants/invaders from modern day Turkey. The people who lived in Western Europe for likely longer that it took for white skin to evolve in the middle east/caucasus(?) region were much darker skinned. Also given how long anatomically modern humans have existed several thousands years is not such a short period.
david-gpu 3y ago
People get this idea that northern US must be at a high latitude just because it is cold in winter, and it simply isn't true. The 49th parallel roughly matches the latitude of Paris, London, Brussels, Munich, Prague or Vienna. The problem isn't that you won't get enough sunlight if you lay down naked in the sun, the problem is that you can't because it is too cold.
- mrcarrot 3y ago
  None of those places are especially sunny in the winter though!
  - david-gpu 3y ago
    But Canada is! And that is what the comment I replied was talking about.
    - ben7799 3y ago
      There is pretty much no place in Canada at all that doesn't have a total blackout of availability of Vitamin D from sunlight in the winter. All the northernmost US states have a period of insufficient sunlight/angle to produce Vitamin D, and basically all of Canada is north of that. Maybe there's an island that is Canadian territory that is south of say New York or San Francisco that I don't know about of course.
- ben7799 3y ago
  No the problem is the sun has to hit the earth's atmosphere at a certain angle in order for the correct wavelengths of light to pass through the earth's atmosphere. The amount of Vitamin D your body can generate from sunlight is based on your skin tone, where you are, the time of day, the day of the year, and the angle of the sun at that time and place. Above/Below a certain latitude (N/S) there is a window of time where the sun never hits that angle at any point during the day, so you could sit outside naked all day long and still get zero vitamin D. If this seems counterintuitive consider if you keep going far enough away from the equator and get into the arctic/antarctic the winter has no sunlight at all, and you clearly can't produce Vitamin D from sunlight if the sun never rises.

The best comment from a vitamin D study I remember is "you can lay buck naked on a rook in January all day but won't get enough vitamin D". Referring to northern US and Canada in winter.

FollowingTheDao 3y ago

It’s insanity to me that the only route people think you should get vitamin D is from the sun. In fact, most of us Caucasian Europeans should be getting it from our diet. Cold water fish has the highest amount of vitamin D.

deleted 3y ago
[deleted]
david-gpu 3y ago
> It’s insanity to me that the only route people think you should get vitamin D is from the sun. In fact, most of us Caucasian Europeans should be getting it from our diet. The fact that the skin of your ancestors rapidly evolved to become much lighter as they migrated to more polar latitudes tells you all you need to know about whether diet was an adequate source of vitamin D. Light-skinned people are particularly well-suited to obtaining all the vitamin D they need from sunlight alone. It is dark-skinned people currently living far from the equator who benefit the most from vitamin D supplementation, because the melanin in their skin reduces their ability to synthesize vitamin D from the meager amount of sunlight they get.
- ffhhttt 3y ago
  It wasn’t very rapid. In most of Europe white skin was introduced by famers migrating from the middle east who displaced the hunter gatherer populations at the beginning of the neolithic.
  - david-gpu 3y ago
    Thousands of years is the blink of an eye in evolutionary terms.
    - ffhhttt 3y ago
      Maybe, but my point is that it initially appeared in the middle east (and probably in northern Eurasia at a similar time) but was likely first introduced throughout most of Europe by migrants/invaders from modern day Turkey. The people who lived in Western Europe for likely longer that it took for white skin to evolve in the middle east/caucasus(?) region were much darker skinned. Also given how long anatomically modern humans have existed several thousands years is not such a short period.

david-gpu 3y ago

People get this idea that northern US must be at a high latitude just because it is cold in winter, and it simply isn't true. The 49th parallel roughly matches the latitude of Paris, London, Brussels, Munich, Prague or Vienna. The problem isn't that you won't get enough sunlight if you lay down naked in the sun, the problem is that you can't because it is too cold.

mrcarrot 3y ago
None of those places are especially sunny in the winter though!
- david-gpu 3y ago
  But Canada is! And that is what the comment I replied was talking about.
  - ben7799 3y ago
    There is pretty much no place in Canada at all that doesn't have a total blackout of availability of Vitamin D from sunlight in the winter. All the northernmost US states have a period of insufficient sunlight/angle to produce Vitamin D, and basically all of Canada is north of that. Maybe there's an island that is Canadian territory that is south of say New York or San Francisco that I don't know about of course.
ben7799 3y ago
No the problem is the sun has to hit the earth's atmosphere at a certain angle in order for the correct wavelengths of light to pass through the earth's atmosphere. The amount of Vitamin D your body can generate from sunlight is based on your skin tone, where you are, the time of day, the day of the year, and the angle of the sun at that time and place. Above/Below a certain latitude (N/S) there is a window of time where the sun never hits that angle at any point during the day, so you could sit outside naked all day long and still get zero vitamin D. If this seems counterintuitive consider if you keep going far enough away from the equator and get into the arctic/antarctic the winter has no sunlight at all, and you clearly can't produce Vitamin D from sunlight if the sun never rises.