Lactation thiamin requirements

Thiamine requirements vary and, with a lack of significant storage capabiHty, a constant intake is needed or deficiency can occur relatively quickly. Human recommended daily allowances (RDAs) in the United States ate based on calorie intake at the level of 0.50 mg/4184 kj (1000 kcal) for healthy individuals (Table 2). As Httle as 0.15—0.20 mg/4184 kJ will prevent deficiency signs but 0.35—0.40 mg/4184 kJ are requited to maintain near normal urinary excretion levels and associated enzyme activities. Pregnant and lactating women requite higher levels of supplementation. Other countries have set different recommended levels (1,37,38). 

Classic beri-beri, rarely seen in the United States and Europe, except in alcoholism (P4), is endemic in the Far East because of the prevalent diet of decorticated rice (F6). It occurs in two forms wet beri-beri, characterized by edema and cardiovascular symptoms (G6), and dry beri-beri with peripheral neuritis, paralysis, and atrophy of the muscles. Conditions which may predispose to deficiency by increasing thiamine requirements are pregnancy (see section 2.4), and lactation, hyperthyroidism, malignant disease, febrile conditions, increased muscular activity, high carbohydrate diets, and parenteral administration of glucose solutions. A constant supply of thiamine is required for optimal nutrition because storage in the liver and elsewhere is limited. Thiamine is synthesized by bacteria in the intestinal tract of various animals, but this is not a dependable source for man. 

The severity of the symptoms of thiamin deficiency has been associated with energy intake. The consumption of large doses of glucose has been foimd to induce an unusual rise in plasma pyruvate and lactate, as well as neurological symptoms, in thiamin deficient humans. Because of this association, the thiamin requirement is sometimes expressed on a per energy intake basis. 

Research Council 1989). Because there are some data indicating lower availability of thiamine in older people, it is recommended that they maintain an intake of Img/day even if they consume less than 2000 kcal (8368 KJ daily). Since thiamine requirements increase during pregnancy and lactation, an additional intake of 0.4mg/day is recommended during pregnancy and 0.5 mg/ day during lactation. 

The dietary requirement for thiamine is proportional to the caloric intake of the diet and ranges from 1.0 - 1.5 mg/day for normal adults. If the carbohydrate content of the diet is excessive then an increased thiamine intake will be required. Requirement is increased in pregnancy and lactation. It also depends of intestinal s)mthesis and absorption and fat content of diet (increased Pyruvate). 

Thiamine deficiency can be assessed by measuring blood levels. Increased blood levels of pyruvate and lactate suggest thiamine deficiency. Measurement of erythrocyte transketolase activity, which requires TPP as a coenzyme, confirms the deficiency. 

Supplement vitamin Bi deficiency states, impaired absorption or increased requirements (pregnancy, lactation, alcoholism) Therapy beriberi, Wernicke s encephalopathy, neuritis, polyneuritis (alcoholic and toxic), neuralgia, myalgia, myocardia, disorders of the intermediate metabolism Thiamine chloride and hydrochloride, thiamine mononitrate, cocarboxylase, thiamine pyrophosphate Tablets, sugar-coated pills, dragees, ampules 50-300 mg 0.3-1.2 mg 1.0-1.4 mg... 

All the strains tested require vitamins for growth, i.e. pantothenic acid and biotin (Delwiche, 1949), some of them need thiamine and / -amino-benzoic acid as well. The growth of all strains is stimulated by Tween 80 (Johnson and Cummins, 1972). Skerman (1967) included also the ability to utilize lactate as a taxonomic character. 

The decarboxylation and oxidation of pyruvate to form acetyl CoA requires the coenzyme thiamin diphosphate, which is formed from vitamin (section 11.6.2). In thiamin deficiency, this reaction is impaired, and deficient subjects are unable to metabolize glucose normally. Especially after a test dose of glucose or moderate exercise they develop high blood concentrations of pyruvate and lactate. In some cases this may be severe enough to result in life-threatening acidosis. 

An intermediate in the catabolism of glucose. If there is inadequate oxygen available, it is converted to lactate (see lactate). If adequate oxygen is available, it is decarboxylated to acetyl-CoA, a reaction which requires, thiamine pyrophosphate as a cofactor. Increased blood pyruvate levels are therefore found in cases of thiamine deficiency. 

Thiamin is the least stored of all the vitamins. The adult human body contains approximately 30 mg. Of the thiamin stored in the body, about 80% is thiamin pyrophosphate, about 10% is thiamin triphosphate, and the remainder is thiamin monophosphate. The liver, kidneys, heart, brain, and skeletal muscles have somewhat higher concentrations than the blood. If the diet is deficient, tissues are depleted of their normal content of the vitamin ini to 2 weeks, so fresh supplies are needed regularly to provide for maintenance of tissue levels. Body tissues take up only as much thiamin as they need with the need increased by metabolic demand (fever, increased muscular activity, pregnancy, and lactation) or by composition of the diet (carbohydrate increases the need for thiamin, while fat and protein spare thiamin). Because thiamin is water soluble, most of the vitamin not required for day-to-day use is excreted in the urine. This means that the body needs a regular supply, and that unneeded intakes are wasted. With a well-balanced diet, approximately 0.1 mg is normally excreted every 24 hours. However, the amount excreted in the urine decreases as the intake becomes inadequate and increases as the intake exceeds body needs because of this, the most widely used biochemical method to assess thiamin status in individuals is the measurement of the vitamin in the urine. 

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