Does anyone know (or know someone who would really know) whether you get Vitamin D during winter by going up altitude in CH?
Nutritionists and scientist agree that because of Switzerland's latitude on earth relative to sun position, inhabitants don't receive Vitamin D from October through April or even after 2pm during the rest of the year.
Thus, most Europeans have low vitamin D and subsequent health problems. One can plot diseases on the globe (such as MS or ovarian cancer) and see that there is a definite north-south gradient, meaning more disease where less Vitamin D.
I once said this to a nutritionist and this person said that during winter months in CH, one could go up in altitude (have a sunny day high up skiing) and that would change the person's position relative to the sun and they could get vitamin D during winter months in CH.
However, this person said it in a way that made me believe they didn't really know this to be scientifically true and was just guessing.
Does anyone know scientifically if this is really true or just one of those hazy myths?
Does anyone know if the Swiss have tested or verified this?
Does anyone know anyone (who would really know) that they could email this question to see if it's true?
I know you definately get more UV radiation at higher altitude, because being higher up means that there is less atmosphere above you to block the sun rays. There is also higher UV radiation because the snow surface reflects it back up.
And because at least you will probably get above the fog
So.. you can definately get strong enough sun to get sunburnt in the alps in the middle of winter. But I think to make enough vitamin D over the whole winter, you would need to be up there exposing some skin to the sun a little bit every day, not just get burnt over one weekend of skiing.
I don't really know about the vitamin D making process, but I think it's quite complicated and depends on lots of things like your skin type etc. Probably differen't for everyone and no one knows the answer exactly..
General advice that I was given is no more than 10 minutes direct sunshine in face and hands without any cover (makeup included)... Once a day, hopefully several times a week if possible...
Problem is, in Zurich you can go three weeks without seeing any sun, and we go from indoors to public transport to offices..which absolutely minimises any chance to go out...
It tends to be sunnier above the clouds, I doubt it is 'altitude' but rather the better thinner air and fewer clouds, therefore more opportunity to catch the sunshine...
If I was in Australia, I would burn in 10-15 minutes in direct sun, even in the middle of winter... Here in Switzerland I almost never sunburn at all...even if I go out all day without sunscreen... I do not have the most sun-sensitive skin, but there are almost no days when I will burn.
It's not just clouds, it's the background pollution as well that filters the UV, plus the lower angle of the sun to the earth means it has to penetrate through more atmosphere, and this reduces the UV.
Its not altitude issue too much rather than sun exposure. Consider in the winter time despite sun you are covered up with clothing and mainly indoors.
Not to mention weather.
In general, populations are Vit D deficient increasing from southern to northern latitudes however there many exceptions depending on nutrition, skin type, sun exposure. For example middle eastern women are generally Vit D deficient ...despite middle east, they have low sun exposure due to covering up and nutritional deficit.
As are some Black African populations in part due to skin pigmentation.
So irrespective of altitude, get some sun and drink your milk. Some advise taking 500 to 1000 IU a day - but so long as your blood values are above 30ng/ml and you're getting dietary Vit D all good. Your body will then activate what it needs and when and where it needs so long as you are Vit D repleat.
I dont bother with any form of supplementation other than McDonalds
It ought to be added that babies cannot create as much vitamin D as adults so they are given supplements here.
Rickets in children is on the increase in the U.K. as parents smother their children in factor 50 sun block, hats and clothing whenever they go outdoors on a sunny day.
You'll produce more vitamin D at altitude in Switzerland in winter, simply because there is more sun (many low-lying areas are fog bound for months at a time).
What Tom say's I believe. Up here in the NE Jura where I live, at 950m- fog is almost unknown in winter- we have loads of sunshine and it's very bright- whereas as soon as you begin to go down towards the lake, fog is increasingly present. i just would go crazy and I'm sure Vitamin D level would drop. There is a good reason why the artisan watch industry started here in winter- in 1770 Breguet made his apprenticeship in a nearby farm- with his workbench on a large South window.
Recently had the visit of a Leicester friend who works with young mums and babies- and there is a huge problem there with some Asian women suffering from severe Vitamin D deficiency- due to lack of sunlight in winter combined with full head to toe and face cover. They actually organise women only gardens on sunny days to allow sun to reach the skin.
Just to clarify .... I do know for sure, that for most of Europe and everything above the latitude of Los Angeles in the US, we do not get Vitamin D from the sun from Oct to April ..... so no matter what you do, you don't get Vitamin D in Zurich in Winter from the sun. Your body saves the Vitamin D, so you are running off stores from Summer.
This is why it's good to get tested in Winter and possibly supplement.
A couple of winters ago a doctor told me "you have next to no Vitamin D in your system" and then soon after I came down with something serious (now rectified).
I am suspect there is some nutritional scientist in a Swiss University who knows the answer to my "D3 in Altitude" question or at least knows more what scientists suspect.
Being married to a guy who grew up in a place where you basically don't see the sun between November and April (if it's up, you don't see it because of the rain), I've taken up his childhood habit of taking cod liver oil supplements. Trollefar and the Troll take it in fish oil form, while I keep to tablets.
At 3000m the UV-B is 60% more intense than at sea level.
So you could get the same UV-B exposure in 37.5% less time or with 37.5% less skin exposure, or a combination of those.
However, given a) the risks from sunburn b) the reality of stripping off at 3000m in the winter, I'd go with the supplements (if necessary) vs cancer or pneumonia.
Edit: this is excluding the impact of Zurich winter fog of course; multiply these differences by a big number for that one.
I agree (hence the if necessary in my post). I think the entire original question is based on a false or at least unverified assumption.
Basing any sort of "vitamin D" link on a simple comparison with latitude is not evidence - general UV exposure, temparature, amount of seasonal variation and quantity of olive oil or red wine consumption probably all show similar gradients.
On the other hand, if there is a vitamin D lack, trying to get it all through your face or nose, or stripping to your undies in the snow, is most likely more risky than taking a multivitamin.
The answer to this as far as I know is 'no' because UVA is blocked more than UVB by the atmosphere. Only UVB photons have enough energy to make the vitamin D precursor molecule but UVA photons can break the same molecule. The sun naturally produces more of the weaker UVA photons but normally this spectrum is filtered by the thick atmosphere. When you go to higher altitude the intensity of UVA increases faster than UVB.
In general though, Norwegians have one of the highest rates of skin cancer in the world, and places near the equator the lowest, so make of that what you will.
Again, perhaps I am wrong, I heard secondhand that Switz doesn't fortify it's milk with Vitamin D like the US (or UK?).
I was told that the Swiss govt often has the philosophy that it doesn't like to force things like this on the population (whereas many other govts believe it is generally good for public health, particularly poorer and less informed populations) and often does not like to encourage mass measures like this and instead leaves the choice up to the individuals to do it for themselves.
Does anyone have any thoughts on this? Does CH milk actually have less D3 than the US because it's not fortified?