Daily nutritional requirements

The adult daily nutritional requirement, which is affected by various factors include weight and size, is about 300 mg/ day. 

TABLE 97-4. Estimating Daily Nutritional Requirements in Adults1,7,19... 

Patient case A patient s daily nutritional requirements have been estimated to be 100 g protein and 2,000 total kcal. The patient has a central venous access and reports no history of hyperlipidemia or egg allergy. The patient is not fluid restricted. The PN solution will be compounded as an individualized regimen using a single-bag, 24-hour infusion of a 2-in-1 solution with intravenous fat emulsion (IVFE) piggybacked into the PN infusion line. Determine the total PN volume and administration rate by calculating the macronutrient stock solution volumes required to provide the desired daily nutrients. The stock solutions used to compound this regimen are 10% crystalline amino acids (CAA), 70% dextrose, and 20% IVFE. 

Coryza it is possible that large daily doses (1 g or more/d) of ascorbic acid (daily nutritional requirement 60 mg) may reduce the incidence and severity of coryza (common cold). Reliable trials in this disease are difficult and the results are inconclusive. To justify use of such doses in populations, benefit must be shown to be clinically, as well as statistically, significant and harm insignificant. This has not been achieved. 

Tocopherols (vitamin E) occur in many food substances that are consumed as part of the normal diet. The daily nutritional requirement has not been clearly defined but is estimated to be 3.0-20.0 mg. Absorption from the gastrointestinal tract is dependent upon normal pancreatic function and the presence of bile. Tocopherols are widely distributed throughout the body, with some ingested tocopherol metabolized in the liver excretion of metabolites is via the urine or bile. Individuals with vitamin E deficiency are usually treated by oral administration of tocopherols, although intramuscular and intravenous administration may sometimes be used. 

SOURCES IN NATURE Humans depend on exogenous sources of vitamin Bj. Vegetables are free of vitamin Bj unless they are contaminated with microorganisms, so that we depend on synthesis in our own alimentary tract or the ingestion of animal products containing vitamin Bjj. The daily nutritional requirement of 3-5 /tg must be obtained from animal by-products in the diet. Despite this, strict vegetarians rarely develop vitamin Bjj deficiency, probably because some vitamin Bj2 is available from legumes and because they often fortify their diets with vitamins and minerals. 

Electrolytes Daily doses based on daily maintenance requirements, renal function, gastrointestinal losses, acid-base status, concomitant drug therapy, nutritional and anabolic status Pa lion I has hyponatremia, hypokalemia, hypomagnesemia, and hypophosphatemia, also has low serum bicarbonate concentration, could be component of metabolic acidosis due to sepsis... 

The diet should meet all nutritional requirements of the species tested and should be free from impurities that might influence the outcome of the test. Dietary contaminants and levels of various nutrients have been shown to alter physiologic processes of animals. Rodents should be fed and watered ad libitum with food replaced at least weekly. When a nonrodent such as the dog is used, it should be fed daily. At present, three types of diets are used conventional (standard), synthetic, and various open-formula diets. Of these, the first two are more widely used in carcinogenicity bioassays. Whichever diet is chosen, suppliers must ascertain by periodic monitoring the nutrient quality and the contaminant level in the basal diet. The researchers should know the effect of the dietary regimen on metabolism and animal longevity. 

In summary, HMG-CoA lyase deficiency is a unique inborn error of metabolism with profound effects on both amino acid catabolism and metabolic homeostasis in the fasted state. Management of these patients is difficult and requires constant attention to daily nutrition and timely intervention during acute illness. Fortunately, nutritional therapy treatment that provides a diet adequate for growth but with limited intake of leucine and prevents fasting and hypoglycemia enables individuals with HMG-CoA lyase deficiency to live normal active lives. 

The amount of zinc that the diet must contain,depends on the availability of zinc for absorption. The WHO committee gives no data for diets, and the suggested daily dietary requirement range from 2.8 mg in infancy to 54.5 mg for lactating women. The United States Food and Nutrition Board suggest a daily intake of 15 mg a day for adults O). 

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... 

Daily protein requirements are based on age, nutrition status, disease state, and clinical condition. The RDA for protein for children is shown in Table 135-10, and for individuals over 18 years of age the RDA is 0.8 g/kg per day, which is much less than most people typically consume. In adults older than 60 years of age, protein needs are increased to 1 g/kg per day to help reduce the loss of LBM that occurs with aging, and up to 1.5 to 2 g/kg per day may be needed in states of metabolic stress such as infection, trauma, and surgery. 

Yang G, Ge K, Chen J, et al. 1988. Selenium-related endemic diseases and the daily selenium requirement of humans. In Bourne GH, ed. World review of nutrition and dietetics. Sociological and medical aspects. Vol. 55. Basel Karger, 98-152. 

The normal daily potassium requirement may be <1200-1500 mg for women and < 1500-1800 mg for men, and the balance of people with this intake is equalized (Anke et al. 2003). The German Society of Nutrition recommends a daily potassium intake of 2 g by adults (Anonymous 2000). 

The best known use of vitamin C is as a nutritional supplement, taken to ensure that one receives his or her daily minimum requirement of the vitamin. The recommended daily allowance (RDA) of vitamin C for adults is 60 milligrams per day. Anyone who eats a well-balanced diet that includes citrus fruits, tomatoes, and green leafy vegetables probably does not need to take a vitamin supplement. However, the amount of vitamin C one normally receives from a supplement is unlikely to cause any harm. 

In addition to the USDA, the National Academy of Sciences Food and Nutrition Board (http //www.iom.edu) publishes the U.S. Recommended Dietary Allowance (RDA) for daily dose requirements of each vitamin (Table 9-1). 

Considerable uncertainty and controversy exists concerning the folate requirement for humans. Hie review of data concerning the human folate requirement by the Food and Nutrition Board (1989) suggests that the daily maintenance requirement is 100-200 fig of avaUable folic acid equivalents. The 1989 RDAs were reduced to 200 and 180 fig for adult men and women, respectively, from the previous RDA of 400 on the basis of such evidence (Food and Nutrition Board, 1989). Similarly, the Canadian RDA for folate was set at 3 /ig/kg body wt or 210 fig for a 70-kg individual. These lower RDAs may be inadequate for certain population groups, however (Sauberlich, 1990 Bailey, 1992 McPartlin etai, 1 3). It is currently difficult or impossible to predict the quantitative effect on folate nutritional status of factors such as (a) changes in folate intake, (b) differences in folate bioavailability, (c) effects of pregnancy and lactation on folate requirements, and (d) pharmaceuticals with antifolate properties. In addition, the development of mathematical models would improve our ability to evaluate methods of nutritional status assessment for this vitamin. 

Although an excess of cobalt can be toxic to animals, there is a wide margin of safety between the nutritional requirement and the toxic level. Cobalt toxicosis is extremely unlikely to occur under practical farming conditions. Unlike copper, cobalt is poorly retained by the body tissues and an excess of the element is soon excreted. The toxic level of cobalt for cattle is 1 mg cobalt/kg body weight daily. Sheep are less susceptible to cobalt toxicosis than cattle and have been shown to tolerate levels up to 3.5 mg/kg. Excessive cobalt supplementation of ruminant diets can lead to the production of analogues of vitamin B12 and a reduction in the quantity of the true vitamin. Cobalt compounds pose a risk to human health as they cause cancer if inhaled and they irritate the skin for this reason, their use has been restricted in the... 

Instant breakfast powders—These powders, which are usually designed to be mixed with a glass of milk, are fortified with minerals and vitamins so as to supply at least one-fourth of the daily nutrient requirement for an adult. Probably they supply better balanced mineral nutrition than most people regularly receive from ordinary types of breakfast foods. However, they may not be suitable for people prone to constipation, unless the low fiber content of the formulas is offset by eating pulpy fruits or drinking unstrained juices. 

These recommended daily allowances provide for a margin of safety to cover variance in individual needs, absorption, and body stores. However, in using this table as a nutritional guide, the following facts should be noted (1) exact daily human requirements of vitamin B-12 cannot be given because it is synthesized by intestinal flora (2) in the absence of intrinsic factor (e.g., pernicious anemia), the vitamin is not absorbed and (3) it is assumed that at least 50% of the vitamin B-12 in food is absorbed. 

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