Thiamine deficiency
Thiamine deficiency is a medical condition of low levels of thiamine (vitamin B1).[1] A severe and chronic form is known as beriberi.[1][7] The name beriberi was possibly borrowed in the 18th century from the Sinhalese phrase බැරි බැරි (bæri bæri, “I cannot, I cannot”), owing to the weakness caused by the condition. The two main types in adults are wet beriberi and dry beriberi.[1] Wet beriberi affects the cardiovascular system, resulting in a fast heart rate, shortness of breath, and leg swelling.[1] Dry beriberi affects the nervous system, resulting in numbness of the hands and feet, confusion, trouble moving the legs, and pain.[1] A form with loss of appetite and constipation may also occur.[3] Another type, acute beriberi, found mostly in babies, presents with loss of appetite, vomiting, lactic acidosis, changes in heart rate, and enlargement of the heart.[8]
"Beri beri" redirects here. For the African ethnic group, see Kanuri people.Thiamine deficiency[1]
Diet of mostly white rice; alcoholism, dialysis, chronic diarrhea, diuretics[1][6]
Food fortification, Food diversification[1]
Uncommon (USA)[1]
Risk factors include a diet of mostly white rice, alcoholism, dialysis, chronic diarrhea, and taking high doses of diuretics.[1][6] In rare cases, it may be due to a genetic condition that results in difficulties absorbing thiamine found in food.[1] Wernicke encephalopathy and Korsakoff syndrome are forms of dry beriberi.[6] Diagnosis is based on symptoms, low levels of thiamine in the urine, high blood lactate, and improvement with thiamine supplementation.[9]
Treatment is by thiamine supplementation, either by mouth or by injection.[1] With treatment, symptoms generally resolve in a few weeks.[9] The disease may be prevented at the population level through the fortification of food.[1]
Thiamine deficiency is rare in the United States.[10] It remains relatively common in sub-Saharan Africa.[2] Outbreaks have been seen in refugee camps.[6] Thiamine deficiency has been described for thousands of years in Asia, and became more common in the late 1800s with the increased processing of rice.[11]
Pathophysiology[edit]
Thiamine in the human body has a half-life of 17 days and is quickly exhausted, particularly when metabolic demands exceed intake. A derivative of thiamine, thiamine pyrophosphate (TPP), is a cofactor involved in the citric acid cycle, as well as connecting the breakdown of sugars with the citric acid cycle. The citric acid cycle is a central metabolic pathway involved in the regulation of carbohydrate, lipid, and amino acid metabolism, and its disruption due to thiamine deficiency inhibits the production of many molecules including the neurotransmitters glutamic acid and GABA.[42] Additionally, thiamine may also be directly involved in neuromodulation.[43]
Epidemiology[edit]
Beriberi is a recurrent nutritional disease in detention houses, even in this century. In 1999, an outbreak of beriberi occurred in a detention center in Taiwan.[51] High rates of illness and death from beriberi in overcrowded Haitian jails in 2007 were traced to the traditional practice of washing rice before cooking; this removed a nutritious coating which had been applied to the rice after processing (enriched white rice).[52] In the Ivory Coast, among a group of prisoners with heavy punishment, 64% were affected by beriberi. Before beginning treatment, prisoners exhibited symptoms of dry or wet beriberi with neurological signs (tingling: 41%), cardiovascular signs (dyspnoea: 42%, thoracic pain: 35%), and edemas of the lower limbs (51%). With treatment, the rate of healing was about 97%.[53]
Populations under extreme stress may be at higher risk for beriberi. Displaced populations, such as refugees from war, are susceptible to micronutritional deficiency, including beriberi.[54] The severe nutritional deprivation caused by famine also can cause beriberis, although symptoms may be overlooked in clinical assessment or masked by other famine-related problems.[55] An extreme weight-loss diet can, rarely, induce a famine-like state and the accompanying beriberi.[23]
Workers on Chinese squid ships are at elevated risk of beriberi due to the simple carbohydrate-rich diet they are fed and the long period of time between shoring. Between 2013 and 2021, 15 workers on 14 ships have died with symptoms of beriberi.[56]
Other animals[edit]
Poultry[edit]
As most feedstuffs used in poultry diets contain enough quantities of vitamins to meet the requirements in this species, deficiencies in this vitamin do not occur with commercial diets. This was, at least, the opinion in the 1960s.[74]
Mature chickens show signs three weeks after being fed a deficient diet. In young chicks, it can appear before two weeks of age. Onset is sudden in young chicks, with anorexia and an unsteady gait. Later on, locomotor signs begin, with an apparent paralysis of the flexor of the toes. The characteristic position is called "stargazing", with the affected animal sitting on its hocks with its head thrown back in a posture called opisthotonos. Response to administration of the vitamin is rather quick, occurring a few hours later.[75][76]
Ruminants[edit]
Polioencephalomalacia (PEM) is the most common thiamine deficiency disorder in young ruminant and nonruminant animals. Symptoms of PEM include a profuse, but transient, diarrhea, listlessness, circling movements, stargazing or opisthotonus (head drawn back over neck), and muscle tremors.[77] The most common cause is high-carbohydrate feeds, leading to the overgrowth of thiaminase-producing bacteria, but dietary ingestion of thiaminase (e.g., in bracken fern), or inhibition of thiamine absorption by high sulfur intake are also possible.[78] Another cause of PEM is Clostridium sporogenes or Bacillus aneurinolyticus infection. These bacteria produce thiaminases that can cause an acute thiamine deficiency in the affected animal.[79]
Snakes[edit]
Snakes that consume a diet largely composed of goldfish and feeder minnows are susceptible to developing thiamine deficiency. This is often a problem observed in captivity when keeping garter and ribbon snakes that are fed a goldfish-exclusive diet, as these fish contain thiaminase, an enzyme that breaks down thiamine.[80]
Wild birds and fish[edit]
Thiamine deficiency has been identified as the cause of a paralytic disease affecting wild birds in the Baltic Sea area dating back to 1982.[81] In this condition, there is difficulty in keeping the wings folded along the side of the body when resting, loss of the ability to fly and voice, with eventual paralysis of the wings and legs and death. It affects primarily 0.5–1 kg-sized birds such as the European herring gull (Larus argentatus), common starling (Sturnus vulgaris), and common eider (Somateria mollissima). Researchers noted, "Because the investigated species occupy a wide range of ecological niches and positions in the food web, we are open to the possibility that other animal classes may develop thiamine deficiency, as well."[81]p. 12006
In the counties of Blekinge and Skåne, mass deaths of several bird species, especially the European herring gull, have been observed since the early 2000s. More recently, species of other classes seems to be affected. High mortality of salmon (Salmo salar) in the river Mörrumsån is reported, and mammals such as the Eurasian elk (Alces alces) have died in unusually high numbers. Lack of thiamine is the common denominator where analysis is done. In April 2012, the County Administrative Board of Blekinge found the situation so alarming that they asked the Swedish government to set up a closer investigation.[82]
