Beriberi is a syndrome caused by a thiamine (vitamin B1) deficiency. All of the bodys tissues need thiamine, including the brain. People cannot produce thiamine. They can only get it from food or supplements. Thiamine is present in many foods such as dried beans, peas and soybeans, meat, poultry, whole grain cereals and nuts. In the United States, breads and cereals are often fortified with thiamine. People suffering from alcoholism have an increased risk of developing thiamine deficiency. Thiamine deficiency can lead to serious conditions such as heart failure, nerve and brain damage (Wernickes encephalopathy and Korsakoff syndrome). If left untreated, thiamine deficiency can be fatal.