Beriberi

Beriberi is the result of a severe thiamin (vitamin B1) deficiency.

Thiamin (also spelled thiamine) or vitamin B1 is a water-soluble vitamin that plays an essential role in the metabolism of carbohydrates.

Approximately, 5 mg of vitamin B1 can be absorbed daily. However, the body only can store around 30 mg. A deficit of intake of vitamin B1 for around a week or an increase requirement may lead to beriberi.

A thiamin deficiency may be the result of:

• Inadequate thiamin intake
• Excessive loss of thiamin
• Increased requirement for thiamin

Alcoholism is the primary cause of beriberi in industrialized countries. Chronic alcohol consumption is associated with a poor diet with low intake of thiamin among other nutrients. Besides, alcohol reduces the absorption of thiamin in the intestine and decrease the liver storage of thiamin.

Other causes of an inadequate thiamin intake are:

• Inadequate intake in case of fasting.
• People whose staple diet is based on white rice (machine-milled rice), or highly refined staples such as maize, wheat or other grains.
• Consumption of anti-thiamin factors (ATF) in food. ATF are substances in the diet that block the availability of thiamin. They are present in coffee, tea, betel nuts, raw freshwater fish or certain plants (ferns).
• Intake of food with sulphites such as wine.
• Parenteral nutrition (intravenous administration of nutrition) lacking thiamin supplementation.

The causes that may reduce thiamin absorption are:

• Chronic gastrointestinal disorders.
• Bariatric surgery (weight-loss surgery).
• Gastric bypass.
• Malabsorption syndrome.

An excessive loss of or consumption of thiamin, may be due to:

• Pregnancy
• Hyperthyroidism
• Diets high in carbohydrates or saturated fats.
• Strenuous physical exertion.
• Breastfeeding.
• Fever
• Diuretics.
• Peritoneal dialysis.
• Folic acid deficiency that causes an indirect thiamin deficiency.

Infantile beriberi may develop in breast-fed infants (from 2 to 4 months old) whose mothers are thiamin deficient.

Beriberi starts with weakness and later may affect multiple organ systems. There are three main types of beriberi:

• Dry beriberi (paralytic or nervous): The main feature of dry beriberi is peripheral neuropathy. Symptoms include abnormal reflexes, as well as diminished sensation and weakness in the legs and sometimes in the arms.
• Cerebral beriberi or Wernicke's encephalopathy: It is usually seen in alcoholics. The common symptoms are involuntary eye movements (nystagmus), double vision (diplopia), cognitive impairment and stance and gait ataxia (lack of coordination and balance). If left untreated, the neurologic damage can be irreversible and lead to Korsakoff's psychosis that involves a severe amnesia and a confused and apathetic state.
• Wet beriberi (cardiac): Wet beriberi is characterized by cardiovascular manifestations which include enlarged heart (cardiomegaly), rapid heart rate (tachycardia), severe swelling in the legs (peripheral edema), water retention, and ultimately, congestive heart failure. There is an acute and fulminant form of wet beriberi called “shoshin”.

The diagnosis is based on the estimation of blood transketolase activity. It is a measure of the availability of thiamine available for use in in red blood cells (erythrocytes).

In addition, a rapid improvement, once the treatment of beriberi is prescribed, confirms the diagnosis.

The proper treatment of beriberi is the administration of intravenous or intramuscular thiamine that must be followed with oral supplementation. The prognosis is Good and fast in general, except in people who have developed Korsakoff syndrome.

It is recommended to follow a balanced diet with adequate intake of food rich in thiamine and to avoid alcohol and refined cereals. The following foods are rich in thiamine:<7p>