I know that Vitamin D is created in the body with exposure to the sun, but I had some questions:
[ol]
[li]Does it matter if I take in morning sun or afternoon (when the sun is higher in the sky?)[/li][li]Does it matter if I take in summer sun rather than winter sun? I mean, if I need 15 minutes of exposure in the summer, do I need 30 in winter (if I were crazy enough to expose the same amount of skin in both types of weather.)[/li][li]Does glass block the effects? I mean, can I sit sitting room in front of the big glass window and get the same benefit of stepping outside for the same amount of time?[/li][li]Do any man-made lights help create Vitamin D? I mean, which types of rays are needed?[/li][li]How do the animals get theirs? I assume fur does not help, as it blocks the sun’s rays.[/li][/ol]
Unless you have ricketts, you really don’t need to worry about it. You just need a little bit of sunlight to get what you need. It’s not really something you need to extensively plan out.
Untrue, sadly. Vitamin D deficiency is now being recognized as a significant problem in the US and other places.
I don’t have the full info at my fingertips, but briefly:
Exposure of arms and legs for 5 to 30 minutes (depending on time of day, season, latitude, and skin pigmentation) between the hours of 10 a.m. and 3 p.m. twice a week is often adequate.
Exposure to one Minimal Erythemal Dose (the least amount of UV exposure that results in pigmentation without sunburn) while wearing only a bathing suit is equivalent to ingestion of approximately 20,000 IU of vitamin D.
My apologies, I’m grumpy and every time I phrase this is sound snarky, but - I was asking for *information *and not advice.
Light absorption by vitamin D precursors is greatest at 260 to 290 nm. That’s in the UVB range; the same stuff that’ll give you a sunburn.
Any lamp that puts out light at those wavelengths will also stimulate vitamin D production. If the lamps are as bright as the sun in the UV, you can use them as sun substitutes, but most lamps are not that bright.
I was diagnosed with vitamin D deficiency - from a blood test, not just observation - and was put on a MEGA dose for a while, then an over-the-counter large dose daily. This worked GREAT for about a few months. Then I started seeing the same old symptoms, mostly fatique.
Some reading suggests that vitamin D, once opened, does not store well. This makes sense, I tend to buy large bottles, so the D may no longer be viable.
I started sitting outside in just shorts for 20 minutes each day for few days and I’m back to feeling pretty darn good today. This is the first day I can remember in a few months where I don’t feel like I need a nap (yet.)
I can continue to do this for the rest of the summer and for much of the fall - but when winter comes I need to find a viable way to get my vitamin D that doesn’t have a shelf-life. I’m going to chat with my doc about it when I see him again, but I hate to make an appointment for just this - when it is clear that I can get it naturally.
Come winter I’m wondering if a full-sprectum lamp will work, or if I can sit down in my sitting room, which gets plenty of sun - but through a window.
But I also wondered about animals. I don’t have one, don’t need to know, it just seems interesting.
Untrue for people in many areas. My mom’s being treated for vitamin D deficiency right now and according to the literature she was sent home with people this far north generally have 1/2 the normal level people are expected to have (and mom’s level is less than 1/2 of that!).
Doubtful. A full-spectrum light does not emit significant UV, it’s not a sun-lamp. And windows block most UV:
But I suppose that several hours through glass may suffice, you’d need like 200-300 minutes!
Note that after 20 minutes or so of direct full sunlight, human skin stops producing Vit D, it is practically impossible to get too much Vit D from sunlight.
OP, how dark is your skin?
A critical determinant of vitamin D3 production in the skin is the presence and concentration of melanin. Melanin functions as a light filter in the skin, and therefore the concentration of melanin in the skin is related to the ability of UVB light to penetrate the epidermal strata and reach the 7-dehydrocholesterol-containing stratum basale and stratum spinosum. Under normal circumstances, ample quantities of 7-dehydrocholesterol (about 25-50 µg/cm² of skin) are available in the stratum spinosum and stratum basale of the skin to meet the body’s vitamin D requirements,[12] and melanin content does not alter the amount of vitamin D that can be produced.[19] Thus, individuals with higher skin melanin content will simply require more time in sunlight to produce the same amount of vitamin D as individuals with lower melanin content.
**Qadgop the Mercotan ** is correct as usual. Americans now have a much greater problem with too little Vit D. Not enough sunlight, fish or fortified dairy.
"The practical reality is that on average, the U.S. diet provides 100 IU/day. " and dudes need at least 200mg, 400mg is the guideline for an average person.
I am light skinned. My profile’s pic gives an fair representation.
Yes, I was a little out of line. My apologies right back at you.