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Tuesday, April 28, 2009

The ABC's of Vitamins - Vitamin B12

Alas, B12 is the last of the B vitamin family; that is not to say that it is not as interesting as its kin. Vitamin B12 has the most complex chemical structure of all the vitamins and contains a molecule of cobalt. And has been the case with a number of its cousins, B12 is just an inclusive name for all cobalamins that have anti-pernicious anemic activity [say that three times fast :)]. You see, this vitamin was discovered by research into pernicious anemia and was finally isolated in 1948.

The most stable, and most commonly seen, form of B12 is cyanocobalamin. And the two forms that act as co-enzymes in the body are methylcobalamin and adenosylcobalamin. These co-enzymes work with the inactive form of folate to convert homocysteine into methionine. In the process, the inactive folate is activated and goes to work in DNA synthesis, thus making B9 & B12 very symbiotic.

Vitamin B12 can only be found in animals and microorganisms; no plants can make this vitamin. The best sources are organ meats like liver, heart and kidney, but other muscle tissues, milk, cheese, eggs and shellfish are good sources. Because this vitamin is not found in plants, vegans and very strict vegetarians must pay attention to their intake of B12.

We only need about 1 microgram per day, although the USDRI is set at 2.4 micrograms. This seems such a small amount, that you are probably wondering how big of a deal is it? It is really big! While it is rare to be deficient, it is not unheard of and those who suffer from Crohn’s/celiac disease are at a greater risk (along with those vegans/vegetarians). Some of the manifestations of a deficiency are megablastic anemia (aka pernicious anemia), demyelinization of nerve tissues (which is irreversible) and death.

So, we have finally reached the end of the B vitamins, but that doesn't mean that we have finished our conversation on vitamins just yet. The next post will be on our friend Vitamin C, probably the best known and perhaps most talked about vitamin out there. Hope to "C" you back!

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