VITAMIN D

 

 

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IMPORTANT: The information on this site should never be used to self medicate or to self diagnose.  Always contact your health care provider before using any kind of supplementation or making any extreme change in diet.

 

VITAMIN D

“So warm.  What a nice feeling, totally relaxing. Wish he’d stop talking.  Can’t focus.  morgue file happy-sunJust close my eyes for a few seconds.  What! Yes, absolutely, you’re absolutely right. Whatever he’s talking about.  Don’t know.  These deck chairs are really comfortable.  Shouldn’t stay in the sun too long though.  Not good.  No, no I’m listening.  Uh, huh.

Damn I must have been asleep for a while.  Where did he go?  Didn’t even catch his name.  My cell.  20 minutes.   Not too bad.  Better get out of this sun.  Get some sunblock on.

All that info on the news now about skin cancer. Then you hear about how important vitamin D is.  I don’t know.  Its all crazy.  We get vitamin D from the sun but now no sun.  What are we supposed to do, eat pills all the time?  Crazy, it’s just crazy!  Why can’t someone just tell me what to do?”

 

WHAT IS VITAMIN D?

There are several forms of Vitamin D but the ones we are talking about here are the forms called Vitamin D2 and Vitamin D3.  Vitamin D2 is made by plants and D3 is made by the skin from the suns rays.  These are the forms used by the human body.  It is not clear which ones raise the bodies levels of calcitriol or 1,25-dihydroxyvitamin D but D3 is believed to be the most active.

Vitamin D is a fat soluble vitamin.  It has to be metabolised in order for our bodies to be able to use it.  We get it primarily from the sun or in smaller amounts from our diet but it is often necessary in northern climates especially in the winter months to get it through supplements.

Vitamin D itself cannot be used by the body but must have additional carbon and oxygen atoms added to it to allow it to be used.

After it has been synthesised in the epidermis of the skin or consumed in food or supplement form it is transported in the blood stream to the liver or the kidneys where it has those carbon and oxygen atoms added in a process called hydroxylation.

In the liver it is transformed into calcidiol,  the major circulating form of vitamin D and re-enters the blood stream.  It is this form that is measured to ascertain vitamin D levels.

In the kidneys it is transformed into calcitriol the most potent form of vitamin D.  Most of the physiological effects of vitamin D are related to calcitriol.

 

THE JOURNEY

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WHAT  DOES VITAMIN D DO FOR US?

1. Activation of Vitamin D

Vitamin D has its own special ‘transcription factor’  A transcription factor is a protein that binds to certain DNA information sequences or a set of instructions. This transcription factor is called the vitamin D receptor or VDR.  It controls what information is transcribed onto specific RNA which then provides more specific instructions for the carrying out of biological activities in the human body through a complex chain of actions.

adn_in_a_bottle_ocalVitamin D called calcitriol or 1,25-dihydroxyvitamin D is at present known to regulate more than 50 genes. Obviously an incredibly important vitamin for our body’s well being.

 

2. Calcium Balance

Vitamin D helps to maintain an acceptable level of calcium in our blood.   Our bodies like to have a serum calcium level that is maintained within a very narrow range.  This is absolutely necessary for our nervous systems to function normally; for bone growth and for maintaining bone density.

So what does Vitamin D have to do with keeping calcium levels normal?

In our bodies, the form of vitamin D called calcitriol

  1. reabsorbs calcium from the kidneys and most importantly
  2. increases the absorption of calcium from the small intestines

There is a gland called the parathyroid gland which is not related to the thyroid gland but operates independently.  Its purpose in life is to control the levels of calcium in our bodies. If calcium levels drop it signals the release of a hormone called parathyroid hormone or PTH.

PTH calls on the kidneys to convert vitamin D to its form called calcitriol. Calcitriol then goes into action stimulating the release of calcium into the blood.

If there is not enough vitamin D in the blood to be converted so that it can absorb more calcium from the diet or reabsorb it from the kidneys then our body will demineralize bone to get the calcium it needs. Calcium is leached from the bones causing the skeleton to break down.

As you can see it is just as important to get enough Vitamin D as it is to get enough calcium.

 

3. Controlling cancer

When cells are involved in growth they proliferate. Uncontrolled proliferation of cells with certain mutations may lead to diseases like cancer.

When cells are involved in maintaining the body processes they differentiate or specialize.  The process of differentiation leads to a decrease in proliferation therefore a decrease in opportunities for cancer to occur.

The form of vitamin D called calcitriol directly stimulates the differentiation of cells.  It has also been known to induce cancer cell death both in petri dishes and in living organisms.

Because of the vitamin D receptor’s (the transcription factor’s) involvement in the carrying out of DNA’s directions for regulating cell growth and because of the specialization and managed cell death and a wide range of other cell mechanisms which are central to the development or destruction of cancer Vitamin D is in a position to create anticancer activity.

As outlined and referenced in both Wikipedia and the Linus Pauling Institute, study after study has reported a direct link between vitamin D intake and a reduction in cancer. One meta analysis reported that 1000 IU per day reduced colon cancer risk by 50%.  2000 IU a day of vitamin D3 supplement along with a well balanced diet could reduce it by over 70%.   It has also been shown to reduce the risk of breast, ovarian prostate and pancreatic cancers.

 

4. Cardiovascular Disease

Low levels of vitamin D have been connected with hypertension, very low density lipoproteins, impaired insulin metabolism and in one study a 62% higher risk of a cardiovascular event ( heart attack or stroke).  Although vitamin D on its own is not going to prevent cardiovascular disease, in partnership with good nutrition it is a necessity.

 

5. Immunity

The ability of the vitamin D receptor to enhance the immune system on one hand and to suppress it when it gets overactive is potent.

In the immune system it has been shown to trigger signals that increase the activity of natural killer cells and of the white blood cells that are involved in attacking and destroying harmful microorganisms and other foreign invaders in the body.

The form of vitamin D3 called calcitriol  increases the production of a peptide that kills harmful bacteria, viruses and fungi.

Research has shown that there are much higher levels of tuberculosis, flu, pneumonia and risk of infections when there is vitamin D deficiency .

 

6. Autoimmune diseases

Autoimmune diseases  occur when the body instructs its own immune system to attack its own tissues.  It perceives these tissues as foreign invaders.  Attack cells called T cells ( which are also used in normal immune function) are the cells involved in this bizarre behaviour.  Calcitriol has been found to regulate T cell responses when they are involved in autoimmune mode.

Autoimmune diseases include: Type 1 diabetes mellitus (insulin dependent), rheumatoid arthritis,  allergies and multiple sclerosis.

The reason vitamin D deficiency is believed to be one of the factors in developing insulin dependent diabetes, multiple sclerosis and rheumatoid arthritis is that research has shown that the farther north people live the more these diseases occur.  In other words people who live where uv rays from the sun are not as powerful and consequently vitamin D is not made as readily are more likely to develop these diseases.

Of course there are other factors that govern disease development such as genetics, environmental issues and diet .  It is not vitamin D alone that is the solution but proper intake of it could be highly beneficial.

Autoimmune diseases include: Type 1 diabetes mellitus (insulin dependent), rheumatoid arthritis,  allergies and multiple sclerosis.

The reason vitamin D deficiency is believed to be one of the factors in developing insulin dependent diabetes, multiple sclerosis and rheumatoid arthritis is that research has shown that the farther north people live the more these diseases occur.  In other words people who live where uv rays from the sun are not as powerful and consequently vitamin D is not made as readily are more likely to develop these diseases.

Of course there are other factors that govern disease development such as genetics, environmental issues and diet .  It is not vitamin D alone that is the solution but proper intake of it could be highly beneficial.

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A study in northern Finland, where the production of vitamin D from the sun is low because the sun light hours are so limited, gave children during the first year of life 2000 IU of vitamin D per day.  The results produced an 80% reduction in diabetes occurring later in life.

 

HOW MUCH VITAMIN D IS TOO MUCH?            

It is difficult to get too much vitamin D.  In fact getting too much from sun exposure is impossible.   Depending on how much melanin you have in your skin,  20 minutes to 2 hours will supply you with approximately 10,000 IU of vitamin D. Once the body has produced 10,000 IU of vitamin D through sun exposure any further amounts simply degrade.

Melanin is the pigment in the skin.  The darker the skin the more melanin.  It is there to give colour to the skin in humans and to protect the skin against damage from ultra violet rays.  ( Different forms of melanin give colour to plants as well.)  It absorbs harmful UV rays and transforms them into harmless heat.  Melanin dissipates more than 99.9% of absorbed UV radiation as heat, keeping free radicals from destroying the skins DNA which can lead to malignant melanoma.   If you have white skin then staying in the sun longer than 20 minutes without sun block is not a good idea.

It is also difficult to get too much vitamin D from food, as well, because there are not many foods that contain vitamin D.  Wild salmon is the richest food source of vitamin D and would take 35 ounces to get 10,000 IU of it.  Eating two pounds of salmon every day!  Now that’s a lot of salmon.

The only way you might manage to get too much vitamin D is through supplementation.   If you, for some bizarre reason, decided to consume more than 50,000 IU of vitamin D a day for a couple of months, and obviously much less for younger children, then you would probably become toxic.  Vitamin D toxicity induces  a dangerous condition called hypercalcemia which can result in calcification of the heart and kidneys along with bone loss.  Mental retardation and facial deformity may occur in babies if pregnant mothers are hypercalcemic.

(Infants who are given 1000 IU of vitamin D a day for a month can develop toxicity.)

 

HOW MUCH VITAMIN D IS TOO LITTLE?

Studies from information from the National Health and Nutrition Examination Survey concluded that low blood levels of vitamin D were associated with all causes of death no matter what the cause.

400 IU per day will stop you from getting rickets in children and osteomalacia in adults,  diseases that make bones go soft.   So you don’t want to be getting any less than that.  Don’t forget vitamin D is a fat soluble vitamin and is stored by the body in fat.  So if you get lots of sun in the summer you will build up some stores for the winter.  However, 400 IU’s is not what we want to be aiming for.

1000 IU a day can reduce the risk of colon cancer by 50% and breast and ovarian cancer by 30%.  2000 IU per day can lower the risk of breast cancer by over 75% and that’s just what it does  for the destruction of cancer cell.

 

People who need to watch carefully that they get enough vitamin D are:

People with dark skin because their pigment blocks the sun.

The elderly because they have reduced capacity to synthesize vitamin D in their skin.

People who don’t go outside without sunscreen or are covered from head to foot.

People who have difficulty absorbing fat. (people with diseases such as cholestic liver disease or cystic fibroses.)

People with inflammatory bowel disease.

People who are obese.  Vitamin D is stored in fat and can become difficult to access if there is too much fat.

Mothers for babies who are being breast fed.  Human milk only has 25 IU per liter.  Infants need about 400 IU per day.

The Linus Pauling institute recommends 2000 IU daily with an upper limit of 10,000 IU for adults while government health departments in both Europe and North America are hesitant to set the RDA at more than 1000 IU and the upper limit at 2000 IU.  They have just recently taken a giant leap and moved it up from 400 IU.

 

HOW DO WE GET VITAMIN D?

The best source is the sun of course but what about skin cancer you ask?  Well as luck would have it there is a way to help prevent getting skin cancer for the time it takes your body to get that 10,000 IU from the sun.  It comes from what you eat!

Not only does the melanin in our skin protect us from cancer causing oxidative stress from free radicals (excess oxygen molecules gone wild) but so do the vitamins E, C and A.  But, and this is a big but, they do not work alone.  C and E work together and A and E work together synergistically as super antioxidants to protect the skin from the sun’s harmful effects.

The combination of C and E is the most powerful combination.

Another powerful antioxidant against the effects of UV rays on our skin comes from polyphenols in green tea called  ‘epicatechins’.  Taken orally or applied to the skin directly they have protective properties reducing sun induced skin inflammation.  So if you’ve run out of sunblock just make some strong green tea and rub it all over your skin.

Amazing, isn’t it, how nature takes care of us.  When we know how and follow the plan we can live happier and most importantly, healthier lives.

Get Your Vitamin D Levels Tested!

Have your physician administer a calcidiol test (also know as a 25-hyrdoxyvitamin D test). More important than your daily intake of vitamin D are your actual vitamin D blood levels. Optimal vitamin D blood levels are 50 ng/mL (125 nmol/L)‚ according to The Vitamin D Council. http://www.vitamindsociety.org/

Vitamin D toxicity is usually the result of taking supplements in excess, when toxic symptoms occur the serum 25(OH)D levels are usually found to be elevated >150 ng/mL (>375 nmol/L).[38]

 

WHERE DO WE GET VITAMIN D?

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Vitamin D is absorbed through the skin from sunlight or from supplements and foods fortified with vitamin D. The body then converts it into 25-OH vitamin D and then into the active hormone 1,25-dihydroxy vitamin D (1,25OH-D).

 

 

 

REFERENCES:

Wikipedia

http://en.wikipedia.org/wiki/Vitamin_D

Linus Pauling Institute 

http://lpi.oregonstate.edu/infocenter/vitamins/vitaminD/

The Mayo Clinic