AUTHOR Dr. Carlos Orozco (BSc, MSc, ND, MD, PhD, FPAMS).
Thiamin, also called vitamin B1, is a water soluble vitamin used in many different body functions and deficiencies may have far reaching effects on the body, yet very little of this vitamin is stored in the body, and depletion of this vitamin can happen within 14 days.
Thiamin is derived from a substituted pyrimidine and a thiazole which are coupled by a methylene bridge. Thiamin is rapidly converted to its active form, thiamin pyrophosphate, TPP, in the brain and liver.
TPP is necessary as a cofactor for the pyruvate and -ketoglutarate dehydrogenase catalyzed reactions as well as the transketolase catalyzed reactions of the pentose phosphate pathway. A deficiency in thiamin intake leads to a severely reduced capacity of cells to generate energy as a result of its role in these reactions
Biological Function of Vitamin B1:
Thiamin may enhance circulation, helps with blood formation and the metabolism of carbohydrates. It is also required for the health of the nervous system and is used in the biosynthesis of a number of cell constituents, including the neurotransmitter acetylcholine and gamma-amino butyric acid (GABA). It is used in the manufacture of hydrochloric acid, and therefore plays a part in digestion. It is also great for the brain and may help with depression and assist with memory and learning. In children it is required for growth and has shown some indication to assist in arthritis, cataracts as well as infertility.
Thiamin pyrophosphate (TPP) is a required coenzyme for a small number of very important enzymes. The synthesis of TPP from free thiamin requires magnesium, adenosine triphosphate (ATP), and the enzyme, thiamin pyrophosphokinase.
Pyruvate dehydrogenase, a-ketoglutarate dehydrogenase, and branched chain ketoacid (BCKA) dehydrogenase each comprise a different enzyme complex found within cellular organelles called mitochondria. They catalyze the decarboxylation of pyruvate, a-ketoglutarate, and branched-chain amino acids to form acetyl-coenzyme A, succinyl-coenzyme A, and derivatives of branched chain amino acids, respectively, all of which play critical roles in the production of energy from food. In addition to the thiamin coenzyme (TPP), each dehydrogenase complex requires a niacin-containing coenzyme (NAD), a riboflavin-containing coenzyme (FAD), and lipoic acid.