Vitamin D

[Guest guest]

Sunlight is also very good for your eyesight. Essential in fact.

I won't bore you all with an essay on Natural Vision Improvement, which includes the judicious use of sunlight amongst other things, but simply say www.seeing.org

Stewart

 

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Debbie Brand

holistic-health

26 March 2004 05:33

Vitamin D

Hello,I thought the article on CRP interesting and it prompted me to share something I learned recently.Recent research has shown that our bodies absorb the required amount of vitamin D through 20 minutes of sun exposure per day. The recent trend to take vitamin D pills has to do with lifestyles that do not include `sunning'. This is true of: elderly patients, who are no longer taken outside for their daily dose of sunshine; people from Islamic countries, who move overseas and do not have places where they can bare their skin. So, have you had your daily dose of Vitamin D today?Debbie

[Guest guest]

The Secret of Vitamin D Production

By John Cannell, MD

The Vitamin D Council

 

Did you see the recent articles about vitamin D in Newsweek or The

Boston Globe? The headline on the Newsweek article was, " Are

Americans dying from a lack of vitamin D? " Why all this excitement

about vitamin D?

 

We all know that vitamin D (cholecalciferol) is crucial to your

health. But is vitamin D really a vitamin? Is it in the foods humans

normally consume? Although there is some in fatty fish, vitamin D is

not in our diets unless humans first fortify a food, like vitamin D

fortified milk. Nature intended for you to make it in your skin, not

put it in your mouth.

 

http://www.mercola.com/2005/feb/2/vitamin_d_production.htm

So is vitamin D really a vitamin?

 

Unlike any other vitamin, vitamin D is actually a prehormone. It is

your body's only source of potent steroid hormone called calcitriol.

How does this happen naturally? First, your skin makes vitamin D when

sunlight strikes a precholesterol molecule. Then your liver converts

vitamin D into the storage form called calcidiol (25-hydroxy vitamin

D). The body stores calcidiol in the blood and fat for later use.

 

(Your doctor can measure calcidiol with a blood test to find out if

you are vitamin D deficient. Ideal calcidiol [25-hydroxy vitamin D]

levels are between 35-65 ng/ml [87-162 nm/L], year around.)

 

If you have enough calcidiol in your blood, then the real action

starts. Some calcidiol goes to the kidneys to help maintain blood

calcium levels but the real story is in your tissues. Tissues all

over your body convert calcidiol into calcitriol. Calcitriol, or

activated vitamin D, is the most potent steroid hormone in the human

body. It is active in picogram quantities or 1/1,000,000,000,000 of a

gram.

 

Like all steroid hormones, calcitriol works by turning your genes on

and off. That is, in hundreds of tissues throughout your body,

calcitriol demasks your genome! It signals your genes to make

hundreds of enzymes and proteins crucial to maintaining health and

fighting disease.

 

Getting Your Share of Vitamin D

 

All of this happens, only if you get enough vitamin D from sunshine

or supplements. If you totally avoid the sun, recent research

indicates you need about 4,000 units of vitamin D a day! So you can't

get enough vitamin D from milk (unless you drink 40 glasses a day) or

from a multivitamin (unless you take about 10 tablets a day), neither

of which is recommended.

 

If you don't get vitamin D the way Mother Nature intended, from

sunshine, you need to take vitamin D supplements. As many of us get a

lot more vitamin D from sunshine than we think, most need about 2,000

units a day extra. More and more Internet and health food stores are

selling vitamin D.

 

Make sure the vitamin D you buy is pure cholecalciferol. Don't buy a

preparation with vitamin A added. Just plain cholecalciferol.

 

Many of the diseases of modern civilization -- cancer, heart disease,

diabetes, hypertension, periodontal disease, depression and even

obesity -- are now clearly associated with vitamin D deficiency. But

association is not the same as causation. Does vitamin D deficiency

cause many cases of these diseases of modern civilization? We just

don't know. We need the National Institutes of Health to fund more

research on vitamin D. So far, however, they have refused.

 

If you want to understand vitamin D, you need to recognize three

facts that have been generally ignored by all but a few vitamin D

scientists. Aldous Huxley once said, " Facts do not cease to exist,

just because they are ignored. " Two of these ignored facts are simple

and the third is more complex.

 

The Steroid Hormone

 

The first fact you already know. The active form of vitamin D is a

steroid hormone, and the most potent one in the body. Steroid

hormones work by demasking the genome. That is, they enable the

manufacturing of proteins and enzymes by your genetic material, the

stuff of life. So the active form of vitamin D acts by enabling the

genetic expression of proteins and enzymes crucial to health in

hundreds of tissues throughout the body. This fact explains why

vitamin D deficiency is involved in so many different diseases.

 

The second fact changed my life. It made me ask why? The fact is

this: Most of us produce about 20,000 units of vitamin D after about

20 minutes of summer sun. (For most skin types, a full body minimal

erythemal [slight redness] dose of UVB light results in the

production of about 20,000 units of cholecalciferol.) This is about

100 times more vitamin D than the government says you need every day.

 

Ask yourself why? Why would humans make so much vitamin D, so very

quickly? I have thought about it, studied textbooks, researched the

medical literature, asked all the experts, and dedicated the rest of

my professional life to getting others to ask themselves " why. " Why

would we have a steroid hormone system that makes so much substrate

so very quickly?

 

The only answer anyone can come up with is: " Probably for a good

reason. " Science does not know why. Zoologists know nature does not

design systems as complex as the vitamin D steroid hormone system for

no reason. Medical science simply doesn't know why we have the

capacity to make so much vitamin D so quickly.

 

If you think about it long enough, you also will conclude it is

probably for a good reason. Although we don't know why, a few

scientists have been trying to find out why, and gasping at the

breathtaking implications.

 

This second fact also tells you something about the normal human

condition -- and the current deviant one. Before we started living in

buildings and cars, wearing sun-protective clothes and lathering on

the sunblock, we farmed and hunted. Before then, we scavenged naked

in the subequatorial African sun for more than a million years.

 

How much vitamin D did we get then? A lot.

 

We started moving inside during the industrial revolution and now the

move is almost complete. Some of us go for days, weeks, or even

months without letting sunshine strike our skin and make vitamin D.

If we do go in the sun, our dermatologist chides us. Whether good or

bad, this existence is aberrant to the species. Modern sun avoidance

is deviant for homo sapiens.

 

Since we make about 20,000 units of vitamin D with a few minutes of

sunshine (perhaps 10,000 units after our skin tans), human beings

have been used to getting a lot of vitamin D every day, until very

recently. Now, most of us get very little. This is simply deviant.

 

Controlling Nature?

 

The third fact is more complex and has to do with the unique

regulation of the vitamin D steroid hormone system. Steroid hormones

are molecules manufactured from cholesterol that act by affecting a

receptor on the genome. Steroid hormone systems are tightly regulated

by the body. When the levels are too low, the body manufactures more

hormones. When those levels are too high, the body makes less. Not so

with vitamin D.

 

First, unlike other steroid systems, the vitamin D system needs both

cholesterol and sunlight to get started. The body has no way of

obtaining vitamin D unless you go into the sun or take supplements.

Remember, unlike all other steroid hormones, the body cannot

manufacture its own vitamin D from cholesterol. It needs sunshine

too.

 

Of course, until about 300 years ago, humans always had plenty of

sunshine.

 

Remember, the real action is in the tissues. The autocrine (in the

cell) and paracrine (around the cell) vitamin D systems appear to be

turned on full bore all the time. (In scientific terms, the Michaelis

Menton constant is never approached throughout the full range of

physiological substrate concentrations for both calcidiol production

in the liver and calcitriol production in the tissues.)

 

Direct negative feedback does not appear to be operating at

physiological substrate levels for both calcidiol production in the

liver and calcitriol production in the tissues. This implies that

tissue levels may be chronically depleted in modern humans.

Furthermore, we'd have no easy way of knowing if we are depleted

because that has become the normal human state.

 

If the tissue production of calcitriol is turned on full, all the

time, what prevents vitamin D toxicity in humans living in the sun?

First, much of the vitamin D you make is excreted in the bile. The

same may be true for much of the calcidiol your liver makes. In

addition, there are numerous other metabolites of vitamin D. So only

about 1/1000 of your calcidiol is turned into calcitriol. That said,

the tissue production of calcitriol is still running full bore at

normal calcidiol substrate concentrations.

 

So what limits the amount of tissue calcitriol? The skin.

 

After you produce about 20,000 units, sunshine begins to destroy

vitamin D in the skin. In other words, the same sunlight that makes

vitamin D in the first place begins to degrade it. Production equals

destruction.

 

As calcitriol production in the tissues and calcidiol creation in the

liver always function below their biochemical capacity, this means

the rate limiting step for the most potent steroid hormone in the

human body appears to lie in the skin. In a way, it lies in your

behavior, your choice to step into the sun -- or not. This is

biologically unique for any and all steroid hormones.

 

This third complicated set of facts strongly implies a widespread

severe deficiency in modern humans. When steroid hormone systems are

turned on full bore, without periodically turning off, this usually

means the body is always asking for more! Since few of us live naked

in the sun, our vitamin D systems are dry, our calcidiol tanks are

running on low, our tissues are starved for more of the most potent

steroid hormone in the body, and, perhaps, the diseases of

civilization are running rampant.

 

That's what all the excitement is about.

0o0o0o0o0o0o0o0o0less Bush, more trees0o0o0o0o0o0o0o0o0o0

Christian groups were threatening to withdraw their support from any

privatization scheme whatsoever unless Bush tries har