Vitamin B1

It is water-soluble and thermolabile. It intervenes in the regulation of carbohydrate metabolism and nervous system functions. It participates in the oxidative decarboxylation of alpha keto acids (pyruvate and alpha ketoglutarate dehydrogenase) and 2-ketosugars (transketolase). It appears to play a role in nerve conduction in the peripheral nerves.

Consumption of vitamin B1 increases in the presence of high energy expenditure and high carbohydrate content, probably because it is important for sugar metabolism. Thiamine alone, however, cannot improve sports performance; it can only work in synergy with the whole complex of other nutrients.

Its RDA ranges from 0.7 to 1.2 mg/dl in children and 1.2 to 1.5 mg/dl in adults.

Vit.B1 deficiency may be due to: insufficient content, ethylism, malabsorption syndromes, dialysis, thiamine-responsive megaloblastic anaemia, thiamine-responsive lactic acidosis, maple syrup urine disease and subacute necronising encephalopathy (Leigh syndrome). Early manifestations of deficiency are anorexia, muscle cramps, paresthesias and irritability. One can arrive at beri-beri with cardiac symptoms (high cardiac failure with dyspnoea, tachycardia, cardiomegaly and peripheral oedemas) and/or with neurological symptoms (pain, paresthesias, loss of reflexes, vomiting, nystagmus, ophthalmoplegia, fever, confusion, amnesia, confabulation).

Thiamine colours the urine a bright yellow colour, but this effect is completely harmless. Drug interactions: diuretics may increase urinary excretion.

The most important natural sources are: whole grains, legumes, nuts, asparagus, broccoli, liver, soya, yeast, potatoes.

The main plant drugs containing this vitamin are: garlic, oats, milk thistle, fig, ginseng, horse chestnut, raspberry liquorice, mallow, wheat germ oil, dandelion.