Review of dietary assessment methods in public health - National ...

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MethodsA literature search was undertaken to identify available dietary assessment tools for usewith adults and children in a public health setting. Details of the literature search arecontained in Appendix A.Introduction to dietary assessmentThe measurement of dietary intake is complex and presents significant challenges,particularly at a group and population level. The appropriate method of measurementwill depend on the objectives of the surveillance and the types of information required.For example, a policy maker may be interested in dietary intake data to measure thebehavioural response to a campaign to encourage healthy eating, or to estimate thedifferences between the nutrient intake of particular population subgroup. In contrast,a commissioner may require more detailed information about the nutritional status ofa population to determine how nutrition and dietetics services should be resourced andtargeted.In the context of public health nutrition, self-report methods are commonly used tocollect food intake data. This is because they usually use fewer resources thanalternative methods, such as the use of biomarkers b or clinical indicators. cAssessment of food intake is potentially subject to many sources of both random andsystematic error. Studies frequently rely on the accurate reporting of habitual foodintake by a sample of individuals within a population. The recall ability andpsychological characteristics of individuals can influence dietary reporting. For example,an individual may be aware that their diet is unbalanced and so may be reluctant toprovide honest answers to questions, or their recollection of intake may simply beflawed. There is also evidence that participants may report behaviour that theyperceive as socially desirable rather than accurate.Wherever possible, it is important to identify and quantify sources of potential errorswhen assessing food intake, particularly when deriving nutrient intake. Errors can beminimised through careful design of the study and analyses of the data, and this shouldbe taken into account when analysing data or interpreting existing analyses.In principle, all tools should be tested for reliability and validity. Reliability refers to thelikelihood that an instrument or tool will measure the same thing each time it is used –either with the same or a different respondent. Validity refers to how accurately theinstrument reflects the actual behaviour. For example, an instrument that wasdeveloped to monitor population level nutrient intake may not be valid and reliable forevaluating change in dietary intake for a smaller group participating in a healthyeating intervention.Self-report tools can be tested against more reliable and objective methods ofassessment such as doubly labelled water to measure energy intake, or nitrogen orprotein intake. Biomarkers such as these are not subject to the same sources of errorbcBiomarkers are biochemical indicators that can be assessed in blood, bodily fluids, body tissues or excretaand provide an indication of a limited number and range of nutrient levels.A number of nutritional deficiencies can be identified from the physical appearance of the body whenclinically examined.NOO | Review of dietary assessment methods in public health 3
and bias as self-report instruments. However, they are expensive and are usuallyimpractical in a public health surveillance context.Further information on dietary assessment can be found in the NOO report ‘Dietarysurveillance and nutritional assessment in England: what is measured and where arethe gaps?’ 1Table 1 lists the eleven tools that have been identified as part of this review andoutlines their main characteristics. More detailed information on each tool is providedin later sections of this report.NOO | Review of dietary assessment methods in public health 4
Page 1 and 2: Review of dietary assessmentmethods
Page 3: IntroductionAccurate and consistent
Page 7 and 8: DietaryAssessmentToolWhat does itme
Page 9 and 10: DietaryAssessmentToolWhat does itme
Page 11 and 12: The CADET is reported to be a relia
Page 13 and 14: The questionnaire was found to show
Page 15 and 16: Five-a-day Community Evaluation Too
Page 17 and 18: categorised as low, medium or high
Page 19 and 20: The authors suggest that the SFFQ m
Page 21 and 22: The Cappuccio dietary questionnaire
Page 23 and 24: initially provided to a group of ch
Page 25 and 26: normal weight children, illustratin
Page 27 and 28: Internal consistency was assessed t
Page 29 and 30: ConclusionWhen evaluating dietary o
Page 31 and 32: Appendix AA literature search was u
Page 33: Reader informationTitleReview of di

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