Nutrient requirements assessment

Generation of data on the nutrient content of agricultural products and foods forms the basis for estimating nutrient intakes of populations via dietary surveys, nutritional labelling for consumer protection, nutrition education for consumer food choice, home and institution menu planning and food purchase, and for research in nutrient requirements and metabolism, toxicant chemical composition is used to assess effects of farm management practices, crop culture, and food processing on chemical content and implications for human health. 

The first step before delivering specialized nutrition support is to perform a nutritional assessment and determine nutrient requirements based on the patient s nutritional status and clinical conditions. Collect subjective and objective data to determine a patient s level of nutrition, to identify patients with malnutrition or at risk for malnutrition, and to identify risk factors that may put a patient at risk for nutrition-related problems.1 A nutrition assessment should include 1,19... 

Assessment of nutrient requirements must be made in the context of patient-specific factors (e.g., age, gender, size, disease state, clinical condition, nutrition status, physical activity). 

Cowey, C.B. (1976). Use of synthetic diets and biochemical criteria in the assessment of nutrient requirements of fish. Journal of the Fisheries Research Board of Canada 33,1040-1050. 

Optimal nutrition therapy requires defining the patient s nutrition goals, determining the nutrient requirements to achieve those goals, delivering the required nutrients, and assessing the nutrition regimen. 

Raiten DJ, Talbot JM, Waters JH. Assessment of nutrient requirements for infant formulas. Am J Clin Nutr 1998 115 2089-2110. 

The overall objective of nutrition support therapy is to promote positive clinical outcomes of an illness or improve a patient s quality of life. Four fundamental steps are key to providing optimal care for patients who require nutrition support. They are definition of nutrition goals, determination of nutrient requirements for achievement of the nutrition goals, delivery of the required nutrients, and subsequent assessment of the nutrition regimen. ... 

A patient s nutrition goals can be established after a thorough nutritional assessment (see Chap. 135). Nutrient requirements and an appropriate route for delivery of the required nutrients can then be determined (see Chaps. 136 and 138). Goals of nutrition support include correction of the patient s caloric and nitrogen imbalances, fluid... 

As a result of these factors, the yield of milk may vary over a very wide range. Fortunately, such variations present fittle difficulty in assessing the nutrient requirements of the cow, since yield is easily and conveniently measured. 

After comparing the nutrient requirements of man with those of domestic animals, we must now assess the quantities of nutrients supplied by the latter species to human diets. The contribution of animal products to world food supphes is summarised in Table 25.3. In total, animal products provide about one-sixth of energy supplies and one-third of protein supplies meat is the major contributor, followed by milk and milk products. The figures for individual countries differ considerably from the world averages (Table 25.4). Thus, in North America and most European countries, meat consumption is 30-40 times greater than in the coimtries of Africa and the Indian subcontinent, although for India the discrepancy for milk consumption is not as great. 

Nutritional Assessment of Observed Nutrient Intake 103 Table I. Classes of Criteria Used to Define Satiation of Nutrient Requirements ... 

There is a growing awareness of the limitations of current approaches to the collection and assessment of dietary data. There is a search for new and better methodology. Alternative approaches to both procedures for data collection and to interpretation of collected data have been presented. These appear to represent a considerable improvement on previous strategies. Careful application of these approaches may enhance the accuracy of estimates of nutrient requirements and intakes. By comparing the situation predicted from dietary analyses with that suggested by biochemical studies, an epidemiologic test of the validity of requirement estimates can be undertaken. The approaches described have both immediate operational application and future research implication. 

Other approaches have been used to estimate nutrient requirements, such as metabolic balance studies and nutrient analysis of human milk. However, both of these approaches adopt an arbitrary target value to assess response to various nutrient intakes. For the premature infant, whose actual existence outside the womb is unnatural , it is impossible, other than by arbitrary definition, to define and justify goals. Therefore, although the intrauterine accretion data are based on relatively few observations and may be an underestimate of true intrauterine accretion, they presently represent the most appropriate guideline for establishing minimum growth and nutrient accretion goals in the newborn premature infant. 

LSRO (Life Sciences Research Office). 1998. Assessment of Nutrient Requirements for Infant Formulas. Bethesda, MD LSRO. 

RECOMMENDATION Growth studies should include precise and reliable measurements of weight and length velocity and head circumference. Duration of measurements should cover at least the period when infant formula remains the sole source of nutrients in the infant diet. Appropriate measures of body composition also require assessment. 

Balance studies Accurate assessment of specific nutrients Requires admission to a clinical research center... 

The reactant is referred to as a substrate. Alternatively it may be a nutrient for the growth of cells or its main function may require being transformed into some desirable chemical. The cells select reactants that will be combined and molecules that may be decomposed by using enzymes. These are produced only by living organisms, and commercial enzymes are produced by bacteria. Enzymes operate under mild conditions of temperature and pH. A database of the various types of enzymes and functions can be assessed from the following web site http //www.expasy.ch/enzyme/. This site also provides information about enzymatic reactions. 

Mechanistic Approaches. Adequate and appropriate river-quality assessment must provide predictive information on the possible consequences of water and land development. This requires an understanding of the relevant cause and effect relationships and suitable data to develop predictive models for basin management. This understanding may be achieved through qualitative, semi-quantitative or quantitative approaches. When quantitative or semi-quantitative methods are not available the qualitative approach must be applied. Qualitative assessments involve knowledge of how basin activities may affect river quality. This requires the use of various descriptive methods. An example of this kind of assessment is laboratory evaluation of the extent to which increases in plant nutrients, temperature or flow may lead to accelerated eutrophication with consequent reduction of water quality. 

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