Beriberi is rare in the United States. The disease often occurs in developing countries among people with a diet that consists mostly of white rice or highly refined carbohydrates. Thiamine deficiency can develop within 2-3 months of a deficient intake and can cause disability and death.
Thiamine is required for the production of ribose, RNA, DNA, nicotinamide adenine dinucleotide (NAD), and adenosine triphosphate (ATP). It is particularly important in tissues that are highly metabolically active, including neurons, cardiac myocytes, and erythrocytes, all of which rely on glucose as a main energy substrate.
Thiamine deficiency leads to impaired glucose metabolism, decreased delivery of oxygen by red blood cells, cardiac dysfunction, failure of neurotransmission, and neuronal death.
Early symptoms of thiamin deficiency are nonspecific: fatigue, irritability, poor memory, sleep disturbances, precordial pain, anorexia, and abdominal discomfort.
There are 2 major manifestations of thiamine deficiency: cardiovascular disease (wet beriberi) and nervous system disease (dry beriberi and Wernicke–Korsakoff syndrome).
Wet beriberi: mainly affects the cardiovascular system, causing poor circulation and fluid buildup in the tissues. Usually presents as predominantly right sided heart failure associated with a high cardiac output or less frequently as cardiovascular collapse.
Dry beriberi: primarily affects and damages the nerves and can lead to decreased muscle strength, eventually muscle paralysis.
In extreme cases, beriberi is associated with Wernicke-Korsakoff syndrome. Wernicke encephalopathy and Korsakoff syndrome are two forms of brain damage caused by thiamine deficiency.
The disorder (or spectrum of disorders) is classically associated with a diet consisting largely of polished rice (oriental beriberi), but may also arise if highly refined wheat flour forms a major part of the diet, and in food faddists (occidental beriberi). Nowadays, beriberi occurs mostly in people who abuse alcohol. Drinking heavily can lead to poor nutrition. Excess alcohol makes it harder for the body to absorb and store vitamin B1.
Manifestation of thiamine deficiency
