Vitamin daily requirement

Vitamin Daily requirement Dosage Ratio Requirem. Dose Decrease of serum cholestero... 

Vitamins A, D, and E are required by mminants and, therefore, their supplementation is sometimes necessary. Vitamin A [68-26-8] is important in maintaining proper vision, maintenance and growth of squamous epitheHal ceUs, and bone growth (23). Vitamin D [1406-16-2] is most important for maintaining proper calcium absorption from the small intestine. It also aids in mobilizing calcium from bones and in optimizing absorption of phosphoms from the small intestine (23). Supplementation of vitamins A and D at their minimum daily requirement is recommended because feedstuffs are highly variable in their content of these vitamins. 

Spinach, salad, cereal germ, and bran as well as pulses are good sources of folic acid. Liver and yeast contain high amounts of this vitamin, too, but are not consumed frequently enough to be relevant for the coverage of daily requirements [1,2]. 

Daily calcium and vitamin D requirements are highest in postmenopausal women and elderly men 1500 mg elemental calcium and 400 to 800 IU vitamin D (see Table 53-4). When these requirements cannot be achieved by diet alone, appropriate calcium and/or vitamin D supplementation is recommended. 

This uncertainty at one point led to the American government having daily requirements for vitamins that were twice those advised by the British government. 

In view of the probable differences in the vulnerability of different tissues in different individuals, it may well be that the vitamin C needs for best health could vary from individual to individual more than the amount of vitamin C necessary for tissue saturation. It may easily be the case, for example, that some individuals are healthy and free from minor symptoms when their tissues are 50 per cent saturated Others, because of the greater vulnerability of specific tissues may require that their tissues be highly saturated at all times. Dalldorf 49 hints at something like resistant vitamin C deficiency when he says, "Even these large amounts [75 to 100 mg. daily], however, are inadequate to maintain saturation in certain patients" (italics added). He cites that in Hodgkins disease, protracted fever from various causes, active rheumatic heart disease, and tuberculosis, the vitamin C requirement may be "extremely high."... 

Only trace amounts of vitamin Bi2 are normally lost in urine and stool. Because the normal daily requirements of vitamin... 

Deficiency of vitamin K in the newborn Newborns have sterile intestines and cannot initially synthesize vitamin K. Because human milk provides only about one fifth of the daily requirement for vitamin K, it is recommended that all newborns receive a single intramuscular dose of vitamin K as prophylaxis against hemorrhagic disease. 

About 1 g of the granules (= 1 sachet) correspond to two daily vitamin B and vitamin C requirements of adults. 

The daily requirements of vitamins by humans are summarized in the entiy on Diet. The relationship between hormones and vitamins is described in the entry 011 Hormones. Vitamins also are mentioned frequently in descriptions of various fruits, vegetables, and other foodstuffs throughout tlie book. Vitamins also figure prominently in discussions of some of the diseases, scores of which are described in this book. 

Vitamin supplements are usually required if the dietary supply of vitamins is inadequate to meet the body s daily requirements.4 In most cases, a relatively balanced diet will provide adequate amounts of all the... 

Recommended daily requirement [RDA) or adequate intake CAQ for men and nonpregnant women over 20 years old. Recommended values for certain vitamins Ce.g., folic acid) may be higher in women who are pregnant. Values for children are typically lower, and are adjusted according to the child s age. 

Vitamin K is essential for the synthesis of coagulation factors II, VII, IX, X, and proteins C and S. About half of the daily requirement is synthesized by the gastrointestinal flora. Deficiency leads to an impairment in the coagulation cascade, clinically presenting as purpura, ecchymoses, and hemorrhage anywhere in the body.29 The recommended daily allowance is 90 fig for females and 120 fig for males.71... 

Vitamin B12 is essential for normal health and development in man and animals. The vitamin is unusual insofar as only very small (microgram) quantities are required to satisfy the daily requirement, yet relatively large quantities are stored in the liver, sufficient to supply normal requirements for a period of at least 3 years. 

Cow s milk contains between 1.6 and 6.2 pg of vitamin B12 per 500 ml and this is sufficient to provide the daily requirement of man. However, if milk is boiled much of the vitamin B12 content may be lost and that remaining may not be sufficient to prevent overt signs of vitamin B12 deficiency. Pasteurization of milk results in the loss of up to 10% of vitamin BI2 (C7). 

B3. Baker, S. J., and Mathan, V. I., Evidence regarding the minimal daily requirement of dietary vitamin B12. J. Clin. Nutr. 34, 2423-2433 (1981). 

Vitamin C cannot be synthesized in the human body and must be obtained from the diet (e.g., citrus fruits, broccoli, turnip greens, sweet peppers, tomatoes) or by taking synthetic vitamin C (e.g., vitamin C tablets, high-C drinks, and other vitamin C-fortified commercial foods). The minimum recommended adult daily requirement of vitamin C to prevent scurvy is 60 mg. Some people, among them the late Linus Pauling, twice Nobel Laureate, suggested that very large daily doses (250 to 10,000 mg) of vitamin C could help prevent the common cold, or at least lessen the symptoms for many individuals. No reliable medical data support this claim. At present, the human quantitative requirement for vitamin C is still controversial and requires further research. 

What is the minimum daily requirement of vitamin C to prevent scurvy in adults ... 

What volume of fruit drink would satisfy your minimum daily vitamin C requirement ... 

Vitamins are essential in mammalian physiology because their coenzyme forms are prosthetic groups or cofactors in many enzyme reactions or because they can perform certain specialized functions in the human organism. Vitamin A and its role in the visual process is an example. The biology of vitamins may be examined from the nutritional or biochemical points of view. The former is concerned with minimum daily requirements, dietary sources, bioavailability, and deficiency syndromes. The biochemist looks for structures, functional groups, conversion to coenzymes, mechanisms of action, mode of transport, and storage. Both aspects will be addressed in this chapter, though the emphasis will be on the biochemical properties of vitamins. 

Milk fat supplies the diet with a substantial proportion of its daily P-carotene and vitamin A requirements. Dietary p-carotene is converted to retinal in the intestinal epithelium and in the liver by the enzyme p-carotene-15-15 -dioxygenase. The retinal formed is further metabolized to retinoic acid (vitamin A). 

The human daily requirement of vitamin E is estimated at 30 IU. Increased intake of polyunsaturated fatty acids increases the need for this vitamin. 

The recommended dietary allowance (RDA) for vitamin D is 5 fig (200 IU)/d, but this value includes casual exposure to sunlight without regard to lifestyle or climate. For individuals who do not receive adequate sunlight because of illness, advanced age, or are otherwise shut in, the actual daily requirement for vitamin D3 could be as much as 15 fig/d. Vitamin D3 deficiency also may occur with chronic biliary obstruction and steatorrhoea limiting intestinal absorption of vitamin D3 and lead to osteomalacia [44], Another factor is the increased use of sunscreens among Western societies, that limits the penetration of UV photons to the site of vitamin D3 synthesis [41,45,46],... 

A priori, the best means of determining vitamin C requirement would seem to be determination of the total body pool and its fractional rate of loss or catabolism. An appropriate intake would then be that to replace losses and maintain the body pool. Clinical signs of scurvy are seen when the total body pool of ascorbate is below 1.7 mmol (300 mg). The pool increases with intake, reaching a maximum of about 8.5 mmol (1,500 mg) in adults -114 /rmol (20 mg) per kg of body weight. The fractional turnover rate of ascorbate is 3% to 4% daily, suggesting a need for 45 to 60 mg per day for replacement. The basis for the 1989 U.S. Recommended Daily Allowance (RDA) of 60 mg (National Research Council, 1989) was the observed mean fractional turnover rate of 3.2% of a body pool of 20 mg per kg of body weight per day, with allowances for incomplete absorption of dietary ascorbate and individual variation. 

Vitamin C has six carbon atoms, each bonded to an oxygen atom that is capable of hydrogen bonding, making it water soluble. Vitamin C thus dissolves in urine. Although it has been acclaimed as a deterrent for all kinds of diseases, from the common cold to cancer, the consequences of taking large amounts of vitamin C are not really known, because any excess of the minimum daily requirement is excreted in the urine. 

The vitamin is present in many foods, especially fresh green peppers, turnip greens, parsnip greens, spinach, orange juice, and tomato juice. The daily requirement of vitamin C is about 60 mg. 

Raskin (R4) tried the DL-tryptophan (10 g) loading test on 12 patients with infectious hepatitis, 72 with chronic hepatitis following the infectious phase, and 5 with Parkinsons disease. It was shown, by the xanthurenic acid test, that the chronic form was accompanied by a disturbance of tryptophan metabolism, and that xanthurenuria persisted even when amounts of pyridoxine were excreted, i.e., in a state of hyper-vitaminosis. Vitamin Bs was therefore well above the minimal daily requirement of the patients, thus showing that other factors are involved in the abnormal excretion of xanthurenic acid. 

The principally pharmacological aspects of vitamins are described here.The nutritional aspects, physiological function, sources, daily requirements and deficiency syndromes (primary and secondary) are to be found in any textbook of medicine. 

Vitamin A Both vitamin A (= retinol) and A2 (= 3-dehydroreti-nol) occur in nature. Like their derivatives, they are classed under the umbrella term axerophtol. The major provitamin is p-carotin. Vitamin A is stored as a lipoglycoprotein complex in the fat-storing cells of the liver. It is released when necessary by being coupled with a retinol-binding protein (RBP) and is then transported to the cells which require vitamin A. In the case of zinc deficiency the rate of RBP synthesis is markedly increased, and as a result serum retinol concentration is reduced. Retinol deficiency can be compensated by zinc substitution. The daily requirement is approx. 1 mg. (7, 36)... 

Vitamin Bj Vitamin Bj was discovered in 1926 by Jansen and Do-NATH, who synthesized it in its crystalline form from rice bran. It was initially called aneurine due to its antipolyneuropathic effect. Because it contains sulphur, Windaus correctly renamed it thiamine in 1932, a term by which it is still known today. The stixicture of this vitamin was described by Williams and Grewe in 1936. It is made up of pyrimidine and thiazole. Thiamine occurs in nature as free thiamine and in the form of thiamine monophosphate, diphosphate and triphosphate. A maximum amount of 8 — 15 mg is absorbed daily in the proximal portion of the small intestine. In the case of oversupply, thiamine is neither stored nor intestinally absorbed. A regular intake, with a daily requirement of about 1 mg, is necessary. The major coenzyme is thiamine pyrophosphate (TPP). Thiamine deficiency may be caused by malnutrition, impaired absorption, alcoholism, antithiamines or a lack of magnesium. Magnesium is an important cofactor for the coenzyme thiamine pyrophosphate. 

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