Minimum daily requirement

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. 

The most common use of salt is as part of daily diets. Although it is added directly to food, 75% of the salt consumed in the United States is a result of eating processed foods The National Academy of Sciences has determined that a minimum daily requirement of 500 mg of sodium is safe, which equates to 1,300 mg of salt. The Academy and the federal government recommend that sodium consumption be no more than 2,400 mg per day, which equals 6,100 mg of salt. Most Americans consume levels higher than this, and many health organizations recommend decreasing salt intake. Excess salt can lead to health problems such as elevated blood pressure, although recent research seems to indicate that normal or moderately... 

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

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. 

In order to understand these complex metabolic interactions more fully and to maximize the information obtained in these studies, we developed a detailed kinetic model of zinc metabolism(, ). Modeling of the kinetic data obtained from measurements of biological tracers by compartmental analysis allows derivation of information related not only to the transient dynamic patterns of tracer movements through the system, but also information about the steady state patterns of native zinc. This approach provides data for absorption, absorption rates, transfer rates between compartments, zinc masses in the total body and individual compartments and minimum daily requirements. Data may be collected without disrupting the normal living patterns of the subjects and the difficulties and inconveniences of metabolic wards can be avoided. 

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. 

It is estimated that the minimum daily requirement of folate is 5 micrograms/kg. Liver stores are about 160 micrograms in premature children, and 220 micrograms in full-term infants. Infants who require parenteral nutrition will rapidly become folate deficient unless fohc acid is included in the regimen. Since many multivitamin supplements do not contain folic acid, its inclusion should be ensured by the addition of folic or folinic acid. 

Based on folate concentrations in liver biopsy samples, and assuming that the liver contains about half of ail body stores, total body stores of folate are estimated to be between 12 and 28 Kinetic studies that show both fast-turnover and very-slow-turnover folate pools indicate that about 0.5% to 1% of body stores are catabolized or excreted daily,suggesting a minimum daily requirement of between 60 and 280)Llg to replace losses. In calculating nutritional requirement, the concept of dietary folate equivalents (DFE) has been used to adjust for the nearly 50% lower bioavailabihty of food folate compared with supplemental folic acid, such that 1 p.g DFE = 0.6 Llg of folic acid from fortified food = 1 j,g of food folate 0.5 p.g foUc acid supplement taken on an empty stomach. Before the fortification program of cereal grains with folic acid conducted between 1988 and 1994, the median intake of folate from food in the United States was approximately 250p.g/day this figure is expected to increase by about 100 Llg/day after fortification. Recommendations... 

The minimum daily requirement for water can be estimated from renal (-1200 mL in urine) and insensible losses (-200 mL due to evaporation from the skin and respiratory tract). Activity, environmental conditions, and disease all have dramatic effects on daily water (and electrolyte) requirements. However, on average, an adult must take in 1.0 to 1.5 L of water daily to maintain fluid balance. Because primary regulatory mechanisms are designed to first maintain intracellular hydration status, uncorrected imbalances in TBW are initially reflected in the ECF compartment. Table 46-1 lists common causes and clinical... 

The minimum daily requirement (MDR) is the smallest amount of a substance needed by a person to prevent a deficiency syndrome. It is considered to represent the body s basic physiological requirement of the material. MDR values, which are established by the U.S. Food and Drug Administration (FDA), are not available for all vitamins. 

The answer is c. (Murray, pp 123-148. Scriver pp 2367-2424. Sack, pp 159-175. Wilson, pp 287-317.) The daily intake of 62.5 g of high-quality protein is above the minimum daily requirement for a 70-kg adult (45 g protein per day). As the obligatory nitrogen losses are covered by the dietary intake, this man will be in nitrogen balance (i.e., 0) and nitrogen loss will equal nitrogen intake. 

The most satisfactory way of determining the daily requirement of a particular nutrient is to devise a diet which is complete except for the nutrient being studied and to feed it to healthy volunteers together with graded supplements of the nutrient in question. The supplement which just finis to produce clinical change when fed over a period of some weeks represents the minimum daily requirement, lliis is easily done with animals, provided a suitable diet can be devised, but there are problems when using humans for this type of study because it may be necessary to take the diet for many weeks or months before clinical signs of a deficiency occur. 

Tryptophan is the least abundant amino acid in most proteins,40 accounting, on the average, for 1 to 1.5% of the total amino acids in typical plant (1%) and animal (1.5%) proteins. A number of foodstuffs, such as corn, are deficient or limited in tryptophan. Because it is present in low concentrations in most tissue proteins, the requirement of tryptophan in the diet is low compared to that of the other amino acids, particularly the other indispensable (essential) amino acids. In human infants, the requirement for growth is roughly 12 to 40 mg/kg. In adult humans, the minimum daily requirement has been estimated to be 250 mg/d in males and 160 mg/d in females.41 Considering the recommended daily allowance for protein is 56 g/d for an adult man and 44 g/d for an adult woman, then this amount would supply between 500 and 700 mg/d of tryptophan, assuming that the protein was of high quality. A typical western diet may supply approximately 600 to 1200 mg L-tryptophan from protein intake.42... 

The minimum daily requirement for protection against detectable scurvy is stated to be 10 mg or even less (K17). British publications set 30 mg as the standard daily requirement (B32), and opinions in the U.S.A. favor as high as 75 mg as the daily adult requirement (N3, G5). The more generous U.S.A. recommendations are based on the allowances which permit the tissue storage within the range found in tissues of animals which synthesize, and therefore do not require, a dietary source of the vitamin, and in human tissues when there is a normal or reasonable intake of antiscorbutic food. ... 

In patients made vitamin K-deficient by a starvation diet and antibiotic therapy for 3—4 weeks, the minimum daily requirement is estimated to be 0.03 pg/kg of body weight and possibly as high as 1 pg/kg, which is approximately the recommended intake for adults (70 pg/day). 

It would be unusual for humans not to obtain 70 milligrams, the minimum daily requirement, of selenium in their diet, since selenium is found in seafood, meat, and grains. Selenium has antioxidant properties as well as beneficial protein functions in the blood and certain tissues. 

Dietary supplements are compotmds that are fotmd naturally in the human body or are part of a normal diet and are sold over-the-coxmter, similar to vitamins. There may be no recommended minimum daily requirement established for a dietary supplement. However, the Food and Dmg Administration follows reports of adverse events so that maximum recommended doses are known and published when appropriate. OTC supplements are bulk products and as such, these compounds are similar to commodity chemicals even though they are sold for human use. 

At one time, a system of MDR (minimum daily requirement) values for nutrients was used. Why do you think Daily Values (DV) might be more informative and useful than MDRs ... 

Figure , (a) Daily release of nafarelin from a cross-linked poly(ortho ester) (POE). Crossbar denotes minimum daily requirement of 0.4 //g/day for estms suppression. Conditions 7.4mm x 20 mm rods prepared from a 3-methyl-l,5-pentanediol prepolymer cross-linked with 1,2,6-hexanetriol and placed into pH 7.4 buffer at 37°C. (b) Percent of female rats showing estms suppression as a function of treatment time with nafarelin-containing POE rods. Devices were prepared from a 3-methyl-1,5-pentanediol prepolymer cross-linked with 1,2,6-hexanetriol and contained 3 wt.% LHRH analog. (After Heller et al, 1987.)... 

The ultimate source of cobalamin for mammalian metabolism is microbial synthesis. The cobalamins from the microbial flora in the gastrointestinal system of herbivorous animals are absorbed by the host and stored by their tissues. From there cobalamin is passed on to other animals in the food chain. A normal daily adult human diet contains about 5 p,g of cobalamin, which is about three times the minimum daily requirement to maintain cobalamin homeostasis. The total amount of cobalamin in the human body is 3 mg. 

---