Comparison of dietary assessment methods in nutritional epidemiology: weighed records v. 24 h recalls, food-frequency questionnaires and estimated-diet records

Abstract

Women (n 160) aged 50 to 65 years were asked to weigh their food for 4 d on four occasions over the period of 1 year, using the PETRA (Portable Electronic Tape Recorded Automatic) scales. Throughout the year, they were asked to complete seven other dietary assessment methods: a simple 24 h recall, a structured 24 h recall with portion size assessments using photographs, two food-frequency questionnaires, a 7 d estimated record or open-ended food diary, a structured food-frequency (menu) record, and a structured food-frequency (menu) record with portion sizes assessed using photographs. Comparisons between the average of the 16 d weighed records and the first presentation of each method indicated that food-frequency questionnaires were not appreciably better at placing individuals in the distribution of habitual diet than 24 h recalls, due partly to inaccuracies in the estimation of frequency of food consumption. With a 7 d estimated record or open-ended food diary, however, individual values of nutrients were most closely associated with those obtained from 16 d weighed records, and there were no significant differences in average food or nutrient intakes. Dietary assessment methods: Weighed intake : Nutritional epidemiologyRecognition of the need for prospective investigation of future individual risk of cancer, and other diseases of middle life, in relation to present day diet is one of the factors that has prompted the search for accurate measures of habitual diet. However, the methodological aims of nutritional epidemiology are inevitably tempered by two opposing interests: that of accuracy in the dietary assessment, and that of feasibility for use in large numbers of individuals, in order to have sufficient power to detect modest relative risks and to demonstrate doseresponse relationships (Bingham, 1987). As part of the preparation for a large European collaborative study of diet and cancer risk (EPIC, European Prospective Investigation of Cancer) we have therefore assessed the accuracy of various methods commonly used in epidemiological studies of diet in large numbers of subjects. We assessed the accuracy of each method by comparison with 16 d of weighed records kept over 1 year.

Associations between dietary flavonoid intakes and bone health in a scottish population

“…The differences may be accounted for in the method of dietary assessment and the length of time over which Kyle's data were collected because longer periods of observation may be required to assess nutrient intakes accurately. (30) Our study population had a healthy diet with greater fruit and vegetable intakes than those reported in the Scottish Health Survey of 2003, which also could explain the high estimated intakes of flavonoids. Flavonoid intakes in the United States calculated using the National Health and Nutrition Examination Survey (NHANES) 1999-2002 dietary records estimate an average of 190 mg/day, which is one-third lower than our estimation.…”

Quality of food eaten in English primary schools: school dinners vs packed lunches

“…However, we feel that foods eaten at lunchtime are particularly suitable for assessment by unweighed food records -as school dinners are served out in standard portion sizes, and packed lunches consisted largely of items that occur in individual units, such as yoghurts, packets of crisps, pieces of fruit, biscuits etc., making estimation of quantities eaten much easier. The use of unweighed records for dietary assessment have been shown to perform well in comparison with weighed records (Bingham et al, 1994). The food and drinks taken by these 7-year-old children were recorded by the parents in discussion with their child, and this may have led to some inaccuracy regarding meals where the parent was not present.…”

Validation of a food frequency questionnaire to assess folate intake of Dutch elderly people

“…A kind of bias with one correction factor could be that all kinds of vegetables are similarly corrected, whereas possibly respondents could estimate some kinds of vegetables better than others. Furthermore, in FFQ inaccuracies in the estimation of portion sizes and the frequency of food consumption are often found 35,31 . This could also be a limitation of our study and could be overcome by administering the FFQ in conjunction with colour photographs of food portion sizes such as A Photographic Atlas of Food Portion Sizes 42 .…”