Thiamine deficiency causes decreased energyproduction because

It is co-enzyme for pyruvate dehydrogenase Thiamine has a central role in energy-yielding metabolism and especially the metabolism of carbohydrates. Thiamine diphosphate is the coenzyme for: A) 3 multi-enzyme complexes that catalyzes oxidative decarboxylation reactions. - pyruvate dehydrogenase complex (catalyzes oxidative decarboxylation of pyruvate to acetyl-CoA) - a-ketoglutarate dehydrogenase in the citric acid cycle and - branched chain keto-acid dehydrogenase involved in the metabolism of leucine, isoleucine and valise. B) Transketolase, in the pentose phosphate pathway. The oxidative decarboxylation of pyruvate and a-ketoglutarate play a key role in energy metabolism of most cells. In thiamine deficiency, the activity of these two dehydrogenase reactions is decreased,, resulting in a decreased production of ATP.