VITAMIN B12 – COBALAMIN

 

 

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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.

 

Genevieve stretched upwards, shears in hand, her tall frame allowed her to clip the upper branches of the old lilac bush.  She could feel the muscles in her back resisting the movement.  Now in her late sixties she still felt strong and fit but the early signs of aging were beginning to creep into her life.  Her husband looked over at her lovingly.  He cherished the life they shared.  She never seemed to grow old in his eyes but he noticed that, lately, she appeared to tire easily.  He was a little worried.

The kitchen screen door suddenly opened banging against the rail.  Genevieve’s friend Nell came out with a large pot of tea and a plate of biscuits.  “Teatime,” Nell announced.

“Oh good, I can rest,” thought Genevieve.

Nell watched as her friend walked towards the patio and joined the other two for a cup of tea.  “Genevieve, what is the matter? You look very tired, dear. Are you ill?”

“Do I?  I hope not.  I do feel very run down though.”

Her husband looked over at Nell.  “I can’t get her to go to the doctor.  I really wish she’d get a check up.”

Nell, who was a dietician suggested that she may need some extra vitamins.  “Sometimes as we get older we need a little help.”  I’m not saying you’re old Gen but even you are getting on just like the rest of us.

“But I take a multivitamin every day Nell. I’m sure I get enough.”

“There is one vitamin you may not be getting enough of though,” said Nell.  Will you try something,  just for me, please.”

“That depends on what you want me to try.”

“I want you to take a B12 tablet every day for a couple of weeks.  Just let it dissolve under you tongue.  And, please make an appointment to see a doctor!”

“Oh, all right.  You two aren’t going to let up until I do are you?” said Genevieve.  “What’s so great about B12 anyway?”

 

WHAT IS COBALAMIN (B12)?

Vitamin B12 or cobalamin is water soluble although unlike most water soluble vitamins 1 to 2.5 mg is stored in the liver and is recycled and reconstituted through bile.  In this way it can be accumulated and stored for years in healthy mature people.

Its structure is the most complex of all the vitamins and is unique amongst them because it contains the rare metal ion cobalt.

Involved in the metabolism of every cell in the body it:

  1. Affects DNA synthesis and regulation;
  2. Affects fatty acid synthesis and energy production.
  3. Plays a key role in brain and nervous system function
  4. Plays a key role in the formation of blood.

Most of the operations performed by vitamin B12 are also performed by folate.  B12 is used to generate folate in the body.

Folic acid can be attained through diet and supplementation thus bypassing the need for B12.  However, B12 is needed directly for certain enzyme activities.

 

THE JOURNEY

VITAMIN-B12-JOURNEY-FOR-WEBWHAT DOES COBALAMIN (B12) DO FOR US?

The two types of B12 that are used by the body are:

  1. methylcobalamin and
  2. 5-deoxyadonosyl cobalamin.

Cobalamin is a cofactor for only 2 enzymes in our bodies but these two enzymes are all pervasive and of prime importance to our very existence.  These two enzymes are:

  1. Methionine synthase
  2. L-methylmalonyl-CoA mutase

1. Methionine synthase needs methylcobalamin in order to function.  Methionine synthase is an enzyme which the B9 vitamin called folate is dependent upon. Without the form of B12 called methylcobalamin to assist in the functioning of methionine synthase folate or vitamin B9 cannot do it’s work.

One of the functions of folate is the production of ‘thymidine‘ which is one of the building blocks for our DNA.  Methionine synthase helps reconstitute the amino acid methionine from another amino acid called homocysteine.  Methionine in turn is used to create a methyl group donor.  This particular methyl group donor called Sam-e for short is used to give methyl groups to our DNA and RNA.

2. Apart from its production of folate B12 is needed directly by certain enzymes. When  L-methylmalonyl-CoA mutase (MCM for short) is converted to another enzyme called succinyl-CoA it requires yet another enzyme that needs 5-deoxyadonosyl cobalamin to do the conversion.  This biochemical reaction is important in getting energy from fats and proteins.  Succinyl CoA is also needed to synthesis the pigment, called haemoglobin, in our red blood cells.

Humans must get B12 from external sources. When we eat food with B12 in it the B12 is usually bound to proteins in the food although unbound crystalline B12 my be taken in as well.

The crystalline form is actually digested by the mucous membranes and absorbed in the mouth.

Protein bound B12 however, begins its digestive process in the stomach where gastric acids release B12 from the proteins.

Once released from the food proteins another group of proteins called R-factor proteins bind to the B12 and at the same time a protein called IF (short for intrinsic factor) is synthesised.  Once in the duodenum or upper intestine the R-factor proteins are dissolved by calcium released by the pancreas and B12 is then able to be bound by the intrinsic factor.

IF will protect B12 from being broken down by bacteria in the intestines. Now known as B12-IF complex it is recognised by the receptors in the upper intestine and is transferred through the wall into the blood stream.

Once in the blood stream it is released from its transporter to become free B12 and at this stage becomes a cofactor for the two enzymes methionine synthase and L-methylmalonyl-CoA mutase.

 

WHAT HAPPENS WHEN WE DON’T GET ENOUGH COBALAMIN (B12) ?

B12 deficiency happens primarily in infants and young children and in people over 60 or in people with an autoimmune condition known as pernicious anaemia.

The young may suffer from a deficiency because B12 builds up stores throughout our lifetime but when we are young these stores have not had time to become sufficiently established if the diet is lacking in B12 so deficiencies may occur.

When we are older many of us suffer from stomach problems causing us to use antacids and thus reducing the acids in our stomach which are so necessary for the releasing of B12 from food.

Pernicious anaemia is a disease that affects the production of intrinsic factor and thus restricts the absorption of B12.

For whatever reason B12 deficiency can lead to many problems throughout our bodies and our lifetimes.

A deficiency can affect:

1. Our nervous system causing numbness and tingling in our arms and legs, memory loss, problems with balance and movement and even dementia.

2. Appetite loss and other digestive problems

3. Problems with elevated homocysteine levels resulting in cardiovascular disease.  Homocysteine levels are regulated by folate (B9), B12 and B6.  B12 helps create methionine from homocysteine.  Methionine is necessary for donating methyl groups in our DNA.  When B12 synthesises methionine it reduces the levels of homocysteine and consequently reduces the risk of heart problems because homocysteine in the blood causes inflammation and a breakdown in blood vessel walls and cartilage.

4. Because folate is needed to activate DNA and because B12 is needed to activate folate a B12 deficiency results in a folate deficiency and consequently our DNA is not properly formed and can results in a heightened risk of cancer cell formation.

5. Depression is yet another risk factor as a result of low levels of B12.  Because B12 is necessary for a healthy nervous system which starts with the neurology of our brains a lack of it often results in problems such as depression.

If you are having stomach problems or suspect that you are not getting enough B12 then letting a B12 supplemental tablet dissolve under your tongue is a good way to bypass the regular root through the digestive tract.  In crystalline form it will be absorbed directly into your blood stream without having to go through the unbinding process when it is consumed in food.

 

 

WHAT HAPPENS WHEN WE GET TOO MUCH COBALAMIN (B12) ?

We don’t  get too much vitamin B12 from either food or from supplements.

 

WHERE DO WE GET COBALAMIN (B12)?

TABLE-FOR-B12


REFERENCES:

WIKIPEDIA

http://en.wikipedia.org/wiki/Vitamin_B12

 

LINUS PAULING INSTITUTE

http://lpi.oregonstate.edu/infocenter/vitamins/vitaminB12/