Vitamin D

[BenBurch]

Reading the recent science press, you would think that Vitamin-D supplements ought to be mandated by law...

Vaginal infections tied to low Vitamin D. http://www.nytimes.com/2009/05/26/health/research/26nutr.html?ref=science

Low Vitamin D tied to cancer risk. http://media-newswire.com/release_1091866.html

Vitamin D tied to mental health. http://www.examiner.com/x-10308-San...m5d25-Fish-a-brain-food-in-more-ways-than-one

Vitamin D improves muscular performance. http://www.foodconsumer.org/newsite..._a_legal_performance_enhancing_substance.html

Vitamin D reduces asthma severity. http://www.foodconsumer.org/newsite...091112_vitamin_d_reduces_asthma_severity.html

Reduces Alzheimers deterioration. http://www.medicalnewstoday.com/articles/151398.php

Of course, its in the milk you consume, but they say not in sufficient amounts to have clinical effects beyond preventing Rickets.

So my question; How much of this is hype, and how much should I believe?

Is this the one real exception to the rule that supplements are unnecessary?

 

[Nursefoxfire]

I seem to recall an article I read saying that only 10 minutes of exposure to direct sunlight per day would provide a person with the requisite amount of Vitamin D.

I'll post the link if I find it.

EDIT: Interesting article from the NIH:
http://ods.od.nih.gov/factsheets/vitamind.asp

 

[BenBurch]

But then you have the skin cancer issue to deal with. I have maintained my pallor for years now for fear of Melanoma...

 

[Soapy Sam]

THEY don't want you to know this, but I'll tell you anyway.

You're going to die anyway.
But you will look pale and interesting...

 

[Perpetual Student]

I seem to recall an article I read saying that only 10 minutes of exposure to direct sunlight per day would provide a person with the requisite amount of Vitamin D.

I'll post the link if I find it.

EDIT: Interesting article from the NIH:
http://ods.od.nih.gov/factsheets/vitamind.asp

Did you read the link you provided?
An important excerpt:

Older adults
Americans aged 50 and older are at increased risk of developing vitamin D insufficiency [28]. As people age, skin cannot synthesize vitamin D as efficiently and the kidney is less able to convert vitamin D to its active hormone form [5,42]. As many as half of older adults in the United States with hip fractures could have serum 25(OH)D levels <12 ng/mL (<30 nmol/L) [6].

People with limited sun exposure
Homebound individuals, people living in northern latitudes (such as New England and Alaska), women who wear long robes and head coverings for religious reasons, and people with occupations that prevent sun exposure are unlikely to obtain adequate vitamin D from sunlight [43,44].

 

[sol invictus]

But then you have the skin cancer issue to deal with. I have maintained my pallor for years now for fear of Melanoma...

The word on the street is that the increased risk of melanoma may be more than counterbalanced by the decreased risk of many other forms of cancer (from the extra vitamin D). So sunblock is bad for you.

 

[BenBurch]

The word on the street is that the increased risk of melanoma may be more than counterbalanced by the decreased risk of many other forms of cancer (from the extra vitamin D). So sunblock is bad for you.

And avoid BOTH by taking D as a pill?

 

[Perpetual Student]

And avoid BOTH by taking D as a pill?

I'm not sure the ant-supplement police would be pleased.

 

[Delvo]

I seem to recall an article I read saying that only 10 minutes of exposure to direct sunlight per day would provide a person with the requisite amount of Vitamin D.

I'll post the link if I find it.

EDIT: Interesting article from the NIH:
http://ods.od.nih.gov/factsheets/vitamind.asp

It says 5-30, which is quite a wide range. You'd be near the bottom end of the range if you are of a light-skinned heritage and you live in a part of the world with a high UV light supply outside, and near the top of it if you are of a dark-skinned heritage and you live in a part of the world with less UV light outside. (I specify the thing about ancestry, instead of just saying it depends on whether you HAVE light or dark skin, because I don't know whether getting a tan affects your vitamin-D production ability.)

 

[sol invictus]

And avoid BOTH by taking D as a pill?

I read somewhere that the oral form doesn't have the same anti-cancer effect. Could be woo, though.

 

[HansMustermann]

Taking vitamin pills sometimes does cause other problems, if you didn't need them to start with.

E.g., typically the vitamin E supplements you get are only synthetic alpha-tocopherol, but taking those actually reduces the concentration of gamma- and delta-tocopherol in your system. And everyone's still unsure exactly what that means for your health, but there you go.

E.g., getting too much vitamin D can produce calcar stones in all sorts of places, including IIRC in blood. Or calcification of soft tissues. Or permanent kidney damage. Or if you also have a parathyroid problem, it can kill at much lower doses than you'd expect.

Also, I'd be weary of taking supplements of any fat-soluble vitamins. The water-soluble ones seem to be benign, or impractically hard to overdose on. The fat-soluble ones are the ones which cells have a bigger problem with regulating, because they pass right through the membrane instead of being regulated by protein "valves" on the membrane. Vitamins A, E and D (in decreasing order of danger) can kill in overdose. Admittedly, A is the real poison there, but I wouldn't go nuts with the other two either.

 

[Cuddles]

Is this the one real exception to the rule that supplements are unnecessary?

No. If you don't get enough vitamin D, via diet or UV exposure, then supplements may be helpful. If you get enough vitamin D in your normal life then supplements are in no way necessary. People who may benefit are mainly old people (which isn't that surprising given that a large proportion are already going to be on various drugs for heart problems and such. Things stop working as you get older.) and those who don't get out enough. If those people want to take supplements, more power to them. There doesn't seem to be any reason to tell everyone to take them.

But then you have the skin cancer issue to deal with. I have maintained my pallor for years now for fear of Melanoma...

I'd be very surprised if getting 10 minutes of Sun per day significantly increases your chance of skin cancer. I get that much just walking to my car.

 

[Nursefoxfire]

Did you read the link you provided?
An important excerpt:

Yes, I read it. I didn't say that article defended my previous claim of 10 minutes exposure per day, I just found it an interesting and substantive article covering Vitamin D.

It says 5-30, which is quite a wide range. You'd be near the bottom end of the range if you are of a light-skinned heritage and you live in a part of the world with a high UV light supply outside, and near the top of it if you are of a dark-skinned heritage and you live in a part of the world with less UV light outside. (I specify the thing about ancestry, instead of just saying it depends on whether you HAVE light or dark skin, because I don't know whether getting a tan affects your vitamin-D production ability.)

Yeah, I noticed that range. I wonder if anyone's done comprehensive skin-testing to see how much exposure, and on what skin tones, gives the best absorption of Vitamin D (i.e. the quickest, so you can avoid long-term exposure to the harmful UV rays). And I'm curious about tans as well, now

I'd be very surprised if getting 10 minutes of Sun per day significantly increases your chance of skin cancer. I get that much just walking to my car.

I think you're right.

One thing I found interesting is that Vitamin D from the sun is blocked by windows. I wonder if harmful UV rays are also blocked. That would totally stink if, through glass, we only reaped the harmful effects of sunlight while being denied our Vitamin D intake!

 

[BenBurch]

Glass is a good UV blocker for UVB. Some modern glasses have coatings to also block some UVA.

 

[Nursefoxfire]

Here's an article about UV light traveling through windows, if anyone's interested.
http://www.uihealthcare.com/topics/medicaldepartments/cancercenter/ultravioletlight/index.html

Ultraviolet B rays are burning rays (blocked by window glass) that are the primary cause of sunburns and skin cancer. Ultraviolet A rays (penetrate through window glass) are able to penetrate deeper into the dermis or the base layer of the skin. UV A rays also contribute to skin burning and cancer. Both UV A and B rays can suppress the immune system, which helps protect against the development and spread of skin cancer.

EDIT: BenBurch posted the same info just before I did, darnit! I'm still looking for information regarding tanning and Vitamin D absorption rates, but no luck so far.

 

[casebro]

NFF, are your looking for vit D PRODUCTION rates?

 

[Dymanic]

Mechanics have a saying: "five quarts of clean oil plus one quart of dirty oil equals six quarts of dirty oil". Where some things are concerned, I think knowledge can be like that: take all the stuff we know and throw it in with all the stuff we don't know, and the end product is something you can't place a lot of confidence in. I see this as one of those areas.

Vitamin D is a hormone produced by the body when stimulated by exposure to sunlight (specifically, ultraviolet B radiation). But exposure to sunlight also has some other physiological effects, downregulation of melatonin production being one of the first that comes to mind. We know that melatonin impacts immunity. We don't know exactly how. Synthesized from serotonin, a neurotransmitter, it has a role in regulation of circadian cycles, and is implicated in Seasonal Affective Disorder, learning and memory, dreaming, and a bunch of other things. These effects would seem to make melatonin a potential confounder in studying Vitamin D. But it gets worse. There may be other confounders we don't even know about yet. There may be synergistic effects, and interdepencies, and effects so specific to nuances of individual physiology that they may serve as barriers to absolute certainty for the forseeable future.

You reach a point, however, where it seems reasonable to conclude that there is enough evidence pointing in a given direction to serve as the basis for making some choices. Tentatively, then, I am sufficiently convinced that Vitamin D plays an important enough role in immunity* that the potential benefits probably outweigh the risks for me. I try to get twenty minutes of full sun exposure every day (I do the back one day and the front the next). On days when I do not anticipate being able to do that, I take 1200 IU by supplement (and 800 IU even when I do).

*and, by facilitating calcium uptake, in maintaining bone density as well -- an item missing from the OP's list, but a concern for me as I am on continuous corticosteroid therapy.

 

[blutoski]

And avoid BOTH by taking D as a pill?

I think the argument is more that unless you're getting less than 5-30 minutes of sunlight daily, you don't need anything more.

ie: you're already getting enough for free, so why pay for an overdose?

 

[BenBurch]

I think the argument is more that unless you're getting less than 5-30 minutes of sunlight daily, you don't need anything more.

ie: you're already getting enough for free, so why pay for an overdose?

The Sun no longer exists. I haven't seen it in YEARS.

 

[Eos of the Eons]

http://ods.od.nih.gov/factsheets/vitamind.asp

Vitamin D is vital for bodily functions. If you are deficient then you need to supplement via food (cod liver oil has lots of vitamin D) or sun exposure, or vitamin supplementation at the recommended daily intake.
Overdosing does not "boost" any effects on the immune system.