Vitamin B1 deficiency

Thiamine, in its active form as thiamine pyrophosphate, acts as a co-factor for three enzymes involved in the metabolism of carbohydrates:

• pyruvate dehydrogenase, in glycolysis
• alpha-ketoglutarate dehydrogenase, in the citric acid cycle
• transketolase, in the pentose phosphate pathway

Consequently, deficiency tends to affect organs dependent on carboyhdrates e.g. the CNS, liver, heart and skeletal muscle.

Body stores of thiamine are small, so a deficiency state appears rapidly if dietary intake is inadequate.

Thiamine is ubiquitous, hence deficiency is only encountered in the following circumstances:

• in countries where the only food is polished rice; this is called beri-beri
• amongst alcoholics who eat almost nothing
• in a starved patient, for example with carcinoma of the stomach