Deficiency of thiamine

Dietary deficiency of thiamine (vitamin 6,j results In an Inability to synthesize thiamine pyrophosphate, and the pathophysiology arises from Impaired glucose utilization, especially manifested In the nervous system. 

Deficiencies of thiamine and B vitamins arising from poor nutrition and malabsorption are usually the basis for these neurological sequelae. 

Til. Role of the Vitamin Thiamine People with beriberi, a disease caused by thiamine deficiency, have elevated levels of blood pyruvate and a-ketoglutarate, especially after consuming a meal rich in glucose. How are these effects related to a deficiency of thiamine ... 

Coenzymes The pyruvate dehydrogenase complex contains five coenzymes that act as carriers or oxidants for the intermediates of the reactions shown in Figure 9.3. Ei requires thiamine pyrophosphate, Ep requires lipoic acid and coenzyme A, and E3 requires FAD and NAD+. [Note Deficiencies of thiamine or niacin can cause serious central nervous system problems. This is because brain cells are unable to produce sufficient ATP (via the TCA cycle) for proper function if pyruvate dehydrogenase is inactive.]... 

Vitamin B1 (thiamine) has the active form, thiamine pyrophosphate. It is a cofactor of enzymes catalyzing the conversion of pyruvate to acetyl CoA, a-ketoglutarate to succinyl CoA, and the transketolase reactions in the pentose phosphate pathway. A deficiency of thiamine causes beriberi, with symptoms of tachycardia, vomiting, and convulsions. In Wernicke-Korsakoff syndrome (most common in alcoholics), individuals suffer from apa thy, loss of memory, and eye movements. There is no known toxicity for this vitamin. 

Diseases and disorders resulting from a deficiency of thiamine include beriben, opisthotonos (in birds), polyneuritis, hyperesthesia, bradycardia, and edema. Rather than a specific disease, beriberi may be described as a clinical state resulting from a thiamine deficiency. In body cells, thiamine pyrophosphate is required for removing carbon dioxide from various substances, including pyruvic acid. Actually, this is accomplished by a decarboxylase of which thiamine pyrophosphate is a part. Where... 

Chronic deficiency of thiamin, especially associated with a high carbohydrate diet, results in beriberi, which is a symmetrical ascending peripheral neuritis. Initially the patient complains of weakness, stiffness, and cramps in the legs, and is unable to walk for more than a short distance. There may be numbness of the dorsum of the feet and ankles, and vibration sense may be diminished. 

Beriberi, a neurologic and cardiovascular disorder, is caused by a dietary deficiency of thiamine (also called vitamin B ). The disease has been and continues to be a serious health problem in the Far East because rice, the... 

The severe deficiency of thiamine produces the disease called Beriberi, which affects the brain, heart, and nerves. This disease is prevalent in the Orient because of the abundance of rice they consume. The rice has been milled which strips the rice of thiamine. 

Elnageh, K. M., and Galtonde, M. R. (1988). Effect of a deficiency of thiamine on brain pyruvate dehydrogenase Enzyme assay by three different methods. /. Ncpipwcff m. 51, 1482-1489. 

Beriberi occurs whenever thiamine intake is less than 0.4 mg/d for an extended period of time. It occurs where polished rice is a dietary staple, and, in Western society, in poor and elderly populations and alcoholics. Beriberi has wet, dry, and cardiac types, and an individual may have more than one type. Wet refers to pleural and peritoneal effusions and edema dry refers to polyneuropathy without effusions. Cardiomyopathy is the principal feature of the cardiac type. An infantile form occurs in breast-fed infants, usually 2-5 months of age, nursing from thiamine-deficient mothers. The symptoms of beriberi remit completely upon thiamine supplementation. A subclinical deficiency of thiamine occurs in hospital patients and the elderly. Deficiency of thiamine and other vitamins may contribute to a generally reduced state of health in these populations. 

Beriberi, a neurologic and cardiovascular disorder, is caused by adi etary deficiency of thiamine (also called vitamin B,). The disease has been and continues to be a serious health problem in the Far East because rice, the major food, has a rather low content of thiamine. This deficiency is partly ameliorated if the whole rice grain is soaked in water before milling some of the thiamine in the husk then leaches into the rice kernel. The problem is exacerbated if the rice is polished, because only the outer layer contains significant amounts ot thiamine. Beriberi is also occasionally seen in alcoholics who are severely malnourished and thus thiamine deficient. The disease is characterized by neurologic and cardiac symptoms. Damage to the peripheral nervous system is expressed as pain in the limbs, weakness of the musculature, and distorted skin sensation. The heart may be enlarged and the cardiac output inadequate. 

Beriberi has been fotmd in people who eat pofished rice (with husks discarded) and few other foods, as thiamin is in the husks of grains. Beriberi is associated with damage to the nervous system, brain, heart, and blood vessels. It is fatal if not treated with adequate amounts of thiamin. Lesser deficiencies of thiamin lead to weakness and fatigue. These lesser deficiencies respond rapidly to thiamin unless they are complicated by another condition, for example, alcoholism, see also Coenzyme. 

In Western societies, gross thiamine deficiency is most often associated with alcoholism. The mechanism for active absorption of thiamine is strongly and directly inhibited by alcohol. Subclinical deficiency of thiamine from malnutrition or anorexia may be common in the general population and is usually associated with multiple vitamin deficiencies. 

Vitamins can be divided into two classes, depending upon the significance of their deficiencies. In affluent countries, deficiencies of thiamin, riboflavin, niacin, ascorbic acid, and folic acid are relatively common but of marginal health significance, while in many parts of the world, deficiencies of these substances are significant and life-threatening. Deficiencies in pyridoxine, pantothenic acid, biotin, vitamin B,2, and the fat-soluble vitamins A, D, E, and K are rare. Because pyridoxine is required for transaminations, required amounts depend upon the quantity of protein in the diet. Biotin, pantothenic acid, and vitamin B,2 are ordinarily not required in the diet. However, a deficiency in vitamin B,2 occasionally occurs, and must be treated by injections of the purified vitamin. 

This psychosis, along with beriberi and polyneuritis, results from a deficiency of thiamine, not of vitamin K. 

Beriberi is a neurological and cardiovascular disorder that is caused by a deficiency of thiamine (also called vitamin Bj). It has been a serious health problem in Asia and continues to be in those places where rice is the main staple food. The problem is exacerbated if the rice is dehusked (polished) because only the outer layers of the seeds contain appreciable amounts of thiamine. Beriberi also occurs in some malnourished chronic alcoholics, so to avoid this problem in some countries certain alcohol-containing drinks are fortified with thiamine. Beriberi is characterized by pain in the limbs, weak muscles, abnormal skin sensation, and an enlarged heart with inadequate cardiac output. Which biochemical processes are affected by thiamine deficiency ... 

The use of oral contraceptive agents (OCAs) is widespread and is being increasingly encouraged in developing countries. Their use has been associated with a number of side effects, in particular, a possible increased risk of thrombotic and embolic vascular disease. There is also evidence that OCAs may affect the metabolism of a number of vitamins. Evidence for deficiency of thiamine, riboflb vin, ascorbic acid, pyridoxine, folic acid, and vitamin B12, and for excess accumulation of vitamin A has been reported. This is of particular concern to populations in which vitamin nutrition may already be suboptimal and has been the subject of recent brief reviews (02, R4, Tl, W13). 

Many of these deficiency conditions in animals can be explained in terms of the role of TPP in the oxidative decarboxylation of pyruvic acid. On a thiamin-deficient diet animals accumulate pyruvic acid and its reduction product lactic acid in their tissues, which leads to muscular weakness. Nerve cells are particularly dependent on the utilisation of carbohydrate and for this reason a deficiency of the vitamin has a particularly serious effect on nervous tissue. Since acetyl coenzyme A is an important metabolite in the synthesis of fatty acids (see p. 220), lipogenesis is reduced. The pentose phosphate pathway is also impaired by a deficiency of thiamin but there is little effect on the activity of the citric acid cycle. 

Vitamin Bi deficiency is shown by a decrease in activity of the enzymes mentioned above. The disease known as beri-beri, which has neurological and cardiac symptoms, results from a severe dietary deficiency of thiamine. 

A deficiency of thiamine causes beri-beri, features of which include emaciation, cardiomyopathy and neurological disturbances. 

Thiamin— Where a deficiency of thiamin exists, a thiamin supplement may be advisable for athletes who consume highly refined carbohydrates or sugar such as dextrose and honey to obtain extra calories. 

This ancient nutritional disease results from a severe deficiency of thiamin (vitamin B-1). It is usually found in areas of the world where diets are high in carbohydrate, but low... 

Vitamins and minerals. Dietary deficiencies of thiamin, riboflavin, niacin, pantothenic acid, vitamin B-6, and vitamin B-12 will modify sensory functions, motor ability, and personality. Deficiencies of minerals such as sodium and magnesium, and toxic intakes of minerals such as lead and mercury, produce mild to severe forms of mental disorders—hyperactivity, learning difficulties, hallucinations, confusion, and giddiness. 

Clinical Effects of Thiamin Deficiency. If a deficiency of thiamin is not corrected (if thiamin is not present in sufficient amounts to provide the key energizing coenzyme factor in the cells), the clinical effects will be reflected in the gastrointestinal system, the nervous system, and the cardiovascular system. Severe thiamin deficiency of long duration will culminate in beriberi, the symptoms of which are polyneuritis (inflammation of the nerves), emaciation and/or edema, and disturbances of heart function. 

SOURCES OF THIAMIN. Some thiamin is found in a large variety of animal and vegetable products but is abundant in few. Therefore, a deficiency of thiamin is a distinct possibility in the average diet, especially when calories are curtailed. 

Beriberi is caused by a deficiency of thiamin (also called thiamine, aneurin(e), and vitamin Bj). Classic overt thiamin deficiency causes cardiovascular, cerebral, and peripheral neurological impairment and lactic acidosis. The disease emerged in epidemic proportions at the end of the nineteenth century in Asian and Southeast Asian countries. Its appearance coincided with the introduction of the roller mills that enabled white rice to be produced at a price that poor people could afford. Unfortunately, milled rice is particularly poor in thiamin thus, for people for whom food was almost entirely rice, there was a high risk of deficiency and mortality from beriberi. Outbreaks of acute cardiac beriberi still occur, but usually among people who live under restricted conditions. The major concern today is subclinical deficiencies in patients with trauma or among the elderly. There is also a particular form of clinical beriberi that occurs in patients who abuse alcohol, known as the Wer-nicke-Korsakoff syndrome. Subclinical deficiency may be revealed by reduced blood and urinary thiamin levels, elevated blood pyruvate/lactate concentrations and a-ketoglutarate activity, and decreased erythrocyte transketolase (ETKL) activity. Currently, the in vitro stimulation of ETKL activity by thiamin diphosphate (TDP) is the most useful functional test of thiamin status where an acute deficiency state may have occurred. The stimulation is measured as the TDP effect. 

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