October 5, 2015

339 Vitamin B12 – the Cobalamins [5 Oct 2015]

B12 is the most structurally complex of the vitamins and the only one which contains a trace mineral – cobalt – which gives it its scientific name cobalamin. That’s the reason cattle are given cobalt, usually in the form of blue salt blocks, so their gut bacteria can synthesize B12 for them. Human gut bacteria may produce some B12 but rarely enough. Thus we need to obtain B12 from our diet.

In order to be absorbed in the small intestine, B12 from our food requires a special enzyme, called “intrinsic factor”, which is produced in the stomach. Some people do not produce enough intrinsic factor, resulting in a B12 deficiency called pernicious anemia. This is overcome with a special sublingual form that is absorbed directly in your mouth, bypassing the digestive tract.

There are three forms of B12 found in supplements.

• Cyanocobalamin is the cheapest form so the most common in multi vitamins. It contains a toxic cyanide group which the body must dispose of after converting it to methylcobalamin. It is safe at normal doses but is not recommended for high dose supplementation.

Methylcobalamin is the biologically active form which protects nerve cells from degenerative damage in neurological disorders such as MS, Alzheimer’s and glaucoma. It is better absorbed and retained than cyanocobalamin and is non-toxic so is safe even at high doses. A quick test for the quality of a multivitamin or B complex is to check the form of B12 in it!

• Hydroxocobalamin is a special form that is well absorbed and is easily converted to the active forms. It is sometimes used in cases of cyanide poisoning to help detoxify and excrete cyanide – by IV for acute toxicity and by supplementation for chronic low-level toxicity. Cyanocobalamin is first converted into hydroxocobalamin and then into either of the active forms – methylcobalamin or adenosylcobalamin. Adenosylcobalamin is readily stored (in the liver) and is the form used in mitochondria for energy production.

B12 plays many roles in our metabolism some of which involve the TCA cycle of energy production in our mitochondria which I wrote about in January 2015 (#302). In March of 2014 (#257) I wrote about B12 deficiency symptoms and the importance of supplementation for brain health.

For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner.

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