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Saturday, February 28, 2009

The ABC's of Vitamins - Vitamin B2

I'd like to introduce you to vitamin B2; it is actually a group of compounds called flavins which contains riboflavin, riboflavin-5'-phosphate (FMN) and riboflavin-5'-adenosyldiphosphate (FAD). Riboflavin's name comes from what it looks like, both physically and chemically. It is a florescent yellow-orange color and flavin comes from flavus meaning yellow in latin the ribo comes from ribitol which is the sugar part of the molecule.

FMN and FAD exist primarily as part of flavoproteins (flavin enzymes) and living cells require them. They work in the oxidoreductive processes - that is they can accept hydrogen atoms - and are used in biological processes like the conversion of pyruvate to acetyl-CoA (for fatty acid metabolism).

This is also one of the vitamins we need to get from our food. Milk, cheese, meat, yeasts, eggs, wheat bran, liver and kidney are all good sources of this vitamin. Riboflavin is absorbed in the intestine; FAD & FMN are converted to riboflavin before they are absorbed. Some of the absorbed riboflavin is converted by the body to FMN and most of that FMN is then converted to FAD in the cells. Vitamin B2 is used in energy production and the conversion of tryptophan to niacin.

Again, this is not a vitamin that is commonly deficient, both due to supplementation and its availability in commonly consumed foods. It doesn't even have any really fun symptoms, you'd most likely experience cracked lips and inflammation of the tongue. Riboflavin is currently being evaluated as a treatment in the prevention of migraines.

So, you've met two of the B vitamins, more to come in the weeks ahead. In the meantime, eat well and be well!

Saturday, February 21, 2009

The ABC's of Vitamins - Vitamin B1

The vitamin du jour is Thiamin (or Thiamine depending on where you are from) which is also known as vitamin B1; it was discovered and named by Robert R. Williams in the early 1930's. Thiamin is found in all plants and animals, but pulses, nuts, cereals/grains, yeasts and pork contain larger quantities than beef, chicken, eggs, veggies and fruits.

Thiamin is not one of the vitamins we can produce so it has to come from our diet. Thiamin is usually found in one of three phosphorylated forms: monophosphate ester, triphosphate ester, and thiamin pyrophosphate (TPP). The triphos form has a role in nerve transmission but the TPP has a much larger role in the body.

TPP is a co-enzyme for several metabolic pathways. It works in the decarboxylation and transketolation processes involved in turning carbohydrates in to energy (tricarboxylic acid cycle). In the body TPP is hydrolyzed to free thiamin in your intestines where it is converted back to TPP in your cells (seems a little silly - huh?). Our cardiovascular and nervous systems need carbohydrates and carbohydrate metabolism needs thiamin - so the amount you need depends is directly dependent on the amount of carbohydrates you eat.

Thiamin is considered to be one of the vitamins with a high bioavailability, probably due to the fact that is most often found in the form our bodies can use (TPP) and because so many foods are supplemented with it, so deficiencies are pretty uncommon. That doesn't mean it can't happen - alcoholics, persons with intestinal issues (especially diarrhea and vomiting), genetic malabsorption issues or those who only eat junk food can all run into issues with deficiency. Some of the symptoms associated with a lack of vitamin B1 are anorexia, muscle weakness, and cardiovascular irregularities. If you really get deficient, you can look forward to paranoia, manic/depressive episodes, confusion and beriberi. Just so you can avoid these conditions keep these facts in mind: thiamin is sensitive to heat and baking soda can inactivate it; while tea and coffee can interfere with its absorption.

So, now you know about the first of the B vitamins - quite a large family as you will see, so come back to meet its cousins!