Nutrient Adequacy Assessment Using Food Consumption Surveys (1986) / Chapter Skim
Currently Skimming:
9. Conclusions and Recommendations
9. Conclusions and Recommendations
Pages 79-94
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 79... ...
or percentages of them, as criteria for the interpretation of observed nutrient intake and that the use of fixed cutoff points may lead to erroneous estimates of the prevalence of inadequate intake. ~ The subcommittee recommends that a probability approach to the interpretation of computed nutrient intake be developed and adopted, where feasible.
|
From page 80... ...
With a multilevel approach, for example, one might look at the intake levels deemed inadequate to prevent clinical manifestations of deficiency, to maintain the functional integrity of metabolic systems, or to maintain high tissue concentrations of nutrients if that level is continued for a long period. Each of these levels is different.
|
From page 81... ...
The probability approach cannot be applied to the interpretation of observed energy intake, even if perfectly measured, because the intake and requirements are highly correlated in well-fed populations such as that of the United States. · The subcommittee recommends that the probability approach not be applied to the interpretation of observed energy intake.
|
From page 82... ...
When no probability assessment can be made for a nutrient, the subcommittee recommends the descriptive presentation of the mean, variance, and percentile distributions. With the probability approach described in this report, one can estimate the absolute prevalence of inadequate dietary intakes, defined as intakes that will not maintain appropriate biochemical stores or functions.
|
From page 83... ...
During the planning of future surveys, the following aspects of the design should be considered: tl) the number and distribution of replicate intakes required for statistically reliable adjustments of the distribution of observed intakes to estimate the distribution of usual intakes for the population and subgroups, (2)
|
From page 84... ...
For example, it is possible to test the effect of incluaing food composition errors in est~mates of the prevalence of inadequate intake. (See examples presented in this report for testing the sensitivity of the prediction to variability of requirement, to errors in estimates of nutrient intake, and to variability of food composition.
|
From page 85... ...
It also recognizes that such improvements may have limited importance for public policy purposes either because there is little or no public health concern about the nutrient and, hence, limited reason to improve precision of estimates or because the missing or unreliable data refer to foods that make a minor contribution to intakes and, hence, whose errors have minimal impact on the estimate of prevalence of inadequate intakes. The subcommittee has not attempted to judge or assess the relative priorities for improving the data base.
|
From page 86... ...
The subcommittee believes that priorities for the acquisition of new analytical data should be based on the contribution of the food to the nutrient intake of the population. Therefore the subcommittee recommends that the USDA perform sensitivity analyses on the imputed values of all foods for which data on key nutrients are missing to determine the probable impact of these foods on the total nutrient intake in the populations of interest.
|
From page 87... ...
The USDA should publish and document the algorithms and procedures used in the computation of the nutrient intakes and their variance, the means and the standard error of the means in food composition data bases, and the prevalence estimates and their variances. · The USDA should publish the concentrations of the individual isomers of the nutrients in food composition data bases, tables, and dietary intake data tapes.
|
From page 88... ...
All members of the subcommittee are in agreement on the scientific validity of the proposed approach and on the nature of these unresolved issues relating to survey design and data base adequacy; however, opinion varied as to the probability of success in developing the Information needed to apply the approach and the time that will be needed for the required research. The subcommittee's judgments are presented under four major areas: acceptable precision of estimates of the prevalence of inadequate intake, estimation of usual food intake, computation of nutrient intake, and definition of nutrient requirements.
|
From page 89... ...
The subcommittee has recommended further research to estimate the magnitude of this bias and to reduce it. This appears to be amenable to satisfactory resolution Through applied research and appropriate survey design, including collaboration with other national surveys.
|
From page 90... ...
Computation of Nutrient Intake As was discussed in Chapter 7, error can also enter into the estimates during the conversion of food intake data into nutrient composition data. This process is dependent on the sampling of foods for chemical analysis, the analytical methods used, the coding categories used to describe foods in the food composition data set, and the computation of nutrient intake.
|
From page 91... ...
Members of the subcommittee agreed that variations in the bioavailability of nutrients will produce errors in estimations of the nutrient intake of a person. However, across individuals, the effect may be no more important than the random under- and overreporting across individuals, as considered earlier.
|
From page 92... ...
. Information about food use, as distinct from nutrient intake, is essential in setting attainable nutritional standards for food assistance programs, for designing meal patterns to meet these programs, and for designing and implementing nutrition education and other nutrition intervention programs intended to ameliorate nutritional problems detected by whatever means in the U.S.
|
From page 93... ...
For this reason, the probability approach has been identified as the preferred method. After examining the use of fixed cutoff points to analyze dietary adequacy, the subcommittee concluded that attempts to estimate absolute prevalence of inadequate intake using the RDAs or any fixed proportion thereof have no scientific validity and that the results of this type of analysis cannot be meaningfully interpreted.
|
From page 94... ...
The subcommittee has proposed an appropriate approach to such interpretation. This application is distinct from an assessment of the state of health consequent to inadequate intake.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.