Nutrient requirements Thiamin

Organism Minimal nutrient requirements Thiamin Pyrimidine Thiazole References (General 309)... 

When large, multicellular organisms developed, vith specialized organs, some of these abilities became a handicap, and were lost. Let us continue with thiamine as an example. All mammals require thiamine in their food, in order to live. The ability to synthesize thiamine was lost by an early ancestral vertebrate, several hundred million or a billion years ago. This animal was ingesting plants, which provided an ample supply of thiamine, about 5 mg for each 2500 kcal of food energy. The sjmthetic mechanism was not needed, and it was a burden it cluttered up the cells, added to the body weight, used energy that could be better used for other purposes. When a series of mutations occurred that eliminated this mechanism, the mutant was favored over the wild type, which failed to meet the competition and died out. The victory of a mutant strain of a bacterium over the wild type in the competition for survival in the presence of an ample supply of the essential nutrient has been verified by direct experiments in the laboratory by Zamenhof and Eichhorn. ... 

Also see ADDITIVES CEREAL GRAINS, section headed "Enriched or Fortified Cereals" CORN, Table C-23 Com Products and Uses for Human Food FLOURS, section headed "Enrichment and Fortification of Flours" IRON, section headed "Sources of Iron" NIACIN, section headed "Sources of Niacin" NUTRIENTS REQUIREMENTS, ALLOWANCES. FUNCTIONS, SOURCES RIBOFLAVIN, section headed "Sources of Riboflavin" RICE, section headed "Nutritional Value" THIAMIN, section headed "Sources of Thiamin" and WHEAT, section headed "Enriched Flour.")... 

Manganese is a cofactor of enzymes involved in energy metabolism and is required for hemoglobin synthesis, thiamin utilization and tendon and bone formation. Unlike nutrients that fulfil unique func-... 

On the other hand, milk is not only an essential food for infants, but for children and adults as well. Children need sufficient nutrients and energy to meet the demands of growth and development. Demands for nutrients such as protein, Ca, Fe, and Zn are relatively high, and teenagers require quite large amounts of B vitamins - thiamine, riboflavin and niacin. In addition, approximately 45 percent of the adult skeleton is laid down during adolescence. 

The population thought to be nxost at risk for Bf, deficiency comprises chronic alcoholics. The deficiency arises fixim a low intakt of the vitamin as well as from alcoho[-induced impairments in the metabolism of the vitamin. An alcoholic deriving of his or her energy requirement from whiskey might be expected to be consuming only 20% of the KDA for vitamin 8, as well as for other nutrients such as protein, folate, and thiamin. 1 he symptoms of deficiency are not specific for this nutrient- They include depression, confusion, and sometimes convulsions. 

Thiamine, a soluble vitamin, is an essential nutrient for humans and is important in carbohydrate metabolism, maintaining normal neural activity and preventing beriberi. Various analytical techniques have been reported for the determination of thiamine in pure form, in pharmaceutical preparations, or in biological fluids. Spectrophotometric methods suffer from poor sensitivity (mg/L detection limit). Spectrofluorometric methods usually involve the conversion of thiamine to thiochrome.2 High performance liquid chromatography requires a post-column derivatization step3 and instrumentation for electrophoresis-based methods is expensive.4... 

The Federal Enrichment Act of 1942 required the millers of flour to restore iron, niacin, thiamin and riboflavin lost in the milling process. Enriched flours and baked goods made from them are now excellent sources of niacin. Niacin may also be found in meat, poultry, fish, whole grains, and peanut butter. Besides direct niacin intake, humans can convert the amino acid tryptophan to niacin. Many people take daily vitamin supplements to ensure they get enough niacin and other essential nutrients, see also Coenzyme Nicotinamide Adenine Dinucleotide. 

At higher ethanol concentrations the intracellular alcohol interferes with membrane organization, increasing its fluidity and permeability to ions and small metabolites and inhibiting transport of nutrients. Especially Ca and Mg ions are able to increase the plasma membrane stability. It has been demonstrated that incorporation of unsaturated fatty acids and/or sterol(s) as well as proteolipids into cellular membrane of yeasts helps to alleviate ethanol tolerance. For the synthesis of the unsaturated fatty acids the presence of traces of oxygen under fermentation conditions is required. Further to Ca and Mg ions, other trace elements such as Co, Cu, Mn and Zn " and vitamins, e.g. pantothenate, thiamine, riboflavin, nicotinic acid, pyridoxine, biotin, folic acid and inositol, are essential for the growth and ethanol production by yeasts. 

Ascorbic acid differs from the other vitamins in that it is required in the diet by only a few species of animals—man, other primates, the guinea pig, an Indian fruit-eating bat, and the red-vented bulbul and some related species of Pas-seriform birds. Other species of animals synthesize ascorbic acid. All mammals and other larger animals require vitamin A, thiamine, riboflavin, nicotinic acid, and pyridoxine as essential nutrients, although microoi anisms usually have the power to synthesize all or most of these substances. 

Due to substrate specificity and low productivity of liposan, a thorough media engineering and novel fermenter design are required to develop a cost-effective technology for liposan production. Thiamine is very important nutrient for Y. lipolytica fermentation for liposan production. Pinchuk et al., proposed a self cycling fermenter with... 

Therapy. Thiamin is necessary for decarboxylation of alpha keto acid therefore, the requirement is proportional to the percentage of carbohydrate in the diet, approximately 0.5 mg/1,000 Kcal (RDA, 1980). The average adult daily intake is close to 0.8 mg, which suggests that some of the population might be marginal in this nutrient. Fortunately, fats and protein have a thiamin-sparing effect. Thiamin is not stored and various outside "stresses such as fever, hyperthyrodism, and trauma seem to influence the need for thiamin. Alcoholics with inadequate diets are particularly susceptible to thiamin deficiency. 

An ingenious and sensitive method elaborated by Van t Hoog makes use of the requirement for thiamine of Drosophila for normal development and metamorphoses. The material to be tested is added in different levels to the nutrient medium on which washed Drosophila eggs are allowed to develop. 

In dogs, the niacin requirement appears to be about ten times that of thiamine.In rats, niacin is an essential nutrient only when the tryptophan content of the diet is low, and under these circumstances requirement is about ten times the thiamine need. The recommended dietary allowances for niacin in this country are ten times the thiamine allowances (Table 1). In view of the above data, these allowances should provide a fair margin of safety. 

MINERAL AND VITAMIN SUPPLEMENTS. There is considerable controversy among nutritionists and pediatricians regarding the amounts and types of nutrient supplements that are required by infants, since breast-fed infants have long been given little or no supplementation. Furthermore, the need for supplementation depends upon a variety of factors such as (1) status of the infant at birth, since preterm or low birth weight infants have higher nutritional requirements to attain the rates of growth and development of normal infants (2) type of milk or formula used (3) affliction of the infant with diarrhea, fever, infection, and/or other stresses and (4) age at which supplemental foods are introduced. It is noteworthy that even breast milk is low in iron, copper, fluoride, vitamins A, D, and E, and biotin, folacin, niacin, thiamin, and vitamin B-6. Furthermore, diluted evaporated milk is notably inferior to breast milk with respect to the contents of iron, zinc, vitamin A, vitamin E, and vitamin C. Therefore, the need for nutrient supplements should be evaluated by a health professional who is familiar with the diet and the overall health status of the infant. 

---