Dietary history questionnaire account for the individual perceptions

The diet history method is a detailed retrospective dietary assessment that obtains details of individual foods, and comprehensive information about foods eaten less regularly [1]. It is used to describe dietary intakes, behaviour, or both over months, a year, or during a specific period in the past. The outcomes measured by dietary history are described in Table D.12.1.

Nutrient intakes obtained by a dietary history are often compared to those obtained by a weighed diary for the purpose of validation. In a small subsample from the Survey in Europe in Nutrition and the Elderly Concerted Action (SENECA) study, for example, reported energy intakes were higher but less than energy expenditure measured by indirect calorimetry [6, 8].

One study compared energy intakes obtained by weighed dietary records and diet histories to energy expenditure estimates obtained by doubly labelled water in children and adolescents. Although mean energy intakes were biased towards overestimation, the differences were small and the authors concluded that the energy intake obtained by a diet history was more representative of habitual intake than the weighed diet diary [2].

Table D.12.1 Dietary outcomes assessed by dietary history.

A dietary history is a retrospective structured interview method consisting of questions about habitual intake of foods from the core food groups (e.g. meat and alternatives, cereals, fruit and vegetables, dairy and ‘extras’) and dietary behaviours (e.g. skipping breakfast, dieting).

The interview technique can use open-ended questions to determine foods and drinks consumed at each meal, followed by specification of amounts. This is followed by a ‘cross-check’ to clarify information about usual intake in the past 3, 6, or 12 months, depending on the aims of the assessment. It can also be combined with a 3-day record or a 24-hour recall.

Usual portion sizes are generally obtained in household measures with/without the use of photographic aids. If a visual aid is used, the approach may necessitate a face-to-face interview and it would be challenging to adapt diet history assessment in a telephone interview or self-administered diet history.

Depending on the participants’ characteristics and the aim(s) of dietary assessment, the interview may put weight on specific dietary items or behaviours. For example, if the target population is pregnant women, diet history often aims to capture use of dietary supplements and experience of food craving. If the research aim is to identify a common dietary habit of people admitted to a hospital during a heatwave or an infectious outbreak, specific food consumption in a specific period may be assessed retrospectively.

Diet history is suitable when the assessment aims to capture detailed information about habitual food intake or food intake at a specific life stage or a specific time period. For example, a large international cohort study, the SENECA [6,8], recruited elderly adults and assessed their diet during one month preceding an interview.

Researchers may be interested in a diet during a specific period. Examples include a diet during pregnancy [7], diets of patients diagnosed with a foodborne illness [4], and diets of victims afflicted by a disaster. In these instances, a diet history method with a structured checklist is well suited to capture dietary exposure during a specific time period.

A few prospective cohorts have been using diet history methods, including Coronary Artery Risk Development in Young Adults (CARDIA) [3] in the United States and Kuopio Ischemic Heart Disease Risk Factor Study [5] in Finland. Diet history would be challenging to implement in a self-administered manner. Practically, diet history requires trained interviewers and it remains unclear whether it would provide more valid and reliable measures of dietary exposure than food frequency questionnaires. For a large-scale prospective study, diet history is not likely to be the primary method of choice.

Estimates of nutrient intakes follow a general procedure that is common with other dietary assessment tools. The following steps are undertaken to estimate nutrient intakes:

1. Mixed meals, if recorded, should be converted to single food items as much as possible. Single food items are supposed to be matched with those in a food composition table.
2. Convert a portion size to gram amounts or amounts in a standard unit (ml for liquids) of each dietary consumption. Frequency should also be standardised to consumption per day or per week.
3. Match all foods and ingredients with items in a food composition table.
4. Obtain nutrient intakes from each food, by calculating a product of an amount of each item consumed per day or per week and nutrients contents per amount of each item.
5. Obtain nutrient intakes per day per individual by calculating a sum of intakes of the nutrient per day per individual. This calculation can be specific to intakes in breakfast or different settings in a day.

Key characteristics of dietary histories are described in Table D.12.2.

1. Individuals need not be literate
2. Covers usual diet in detail, so only one interview is necessary for the particular time period under consideration
3. Details of individual foods are obtained
4. Information is obtained about foods eaten less regularly
5. Energy intake and most nutrients can be estimated reasonably accurately

1. The resulting data depend heavily on the skill of the interviewer
2. Interview-based methods may result in observer bias
3. The individual may not remember past food consumption and be subject to recall bias
4. It may also be difficult for the individual to assess portion sizes of past meals
5. This method is difficult for those with erratic eating habits such as shift workers
6. Individual food coding is necessary; this is a time consuming process requiring trained staff, thus making it expensive

Table D.12.2 Characteristics of dietary histories.

Considerations relating to the use of dietary history for assessing diet in specific populations are described in Table D.12.3.

Table D.12.3 Suitability of diet assessment by dietary history in different populations.