Beriberi is a nutritional disorder caused by a deficiency in vitamin B1, presenting cardiac and neurological symptoms. Infantile beriberi, an important problem in breast-fed infants whose mothers milk is deficient in thiamine, can lead to heart failure. Starving children bodies often show signs of beriberi. The disease has two forms: in dry beriberi, there is a gradual degeneration of the long nerves, of the legs and the arms, with associated atrophy of muscle and loss of reflexes; in wet beriberi, a more acute form, there is oedema resulting in large part from cardiac failure and poor circulation.
Beriberi was first shown conclusively to be a nutritional disease by the Japanese naval surgeon Admiral Takaki. In 1878 the diet in the Japanese navy considered almost entirely of milled rice, and about 30% of the sailors suffered from beriberi each year.
Thiamine deficiency subsists in situations where imbalanced diets are prevalent (rice-eating countries, chronic alcoholism, etc). Refining of foods like sugar, flour and rice removes the thiamine.