Evalue Dieta: Capitulo 3

Study Notes

This chapter outlines various aspects of measuring dietary intake.
The chapter's structure includes sections on reasons, techniques, considerations for specific groups, issues in dietary measurement, and estimating portion sizes.

Assessing and monitoring food and nutrient intake: Evaluating adequacy of intake, identifying malnutrition, tracking trends in food and nutrient consumption, and monitoring contaminants in food are vital aspects of this topic.
Formulating and evaluating government health and agricultural policy: Dietary data is used in developing policies for food production, assistance programs, guidelines, and regulations (e.g., food labeling, fortification).
Conducting epidemiological research: Investigating diet-related diseases and health outcomes and identifying populations at risk involves this process.
Commercial purposes: Food manufacturers use dietary data to develop new products and understand consumer preferences.

"The Big Three": 24-hour recall, food records (diaries), and food frequency questionnaires are common methods.
Less common techniques: Diet history, duplicate food collections, food accounts, food balance sheets, telephone interviews, and technological innovations.

Strengths: Inexpensive, quick, provides detailed information, captures short-term memory, manageable burden for respondents (less stress), and does not directly alter diet.
Limitations: Potential for underreporting or overreporting of certain food types or details. "Flat-slope syndrome" can exist. Intra-individual variability may influence results. Can be used for single day or multiple sessions.
Multiple-Pass Method: Multiple reviews of intake throughout the day; used to reduce underreporting and enhance recall accuracy.
Computer-assisted multiple-pass method: A method used in NHANES (National Health and Nutrition Examination Survey). Involves multiple steps to reduce underreporting of foods. Training for interviewers are essential for success.
USDA's Automated Multiple-pass Method: Uses standardized questions, categorizes food, and collects accurate intake information using structured approach and specific methods.
Food Record (Diet Record, Food Diary): The study participants document their daily dietary intake over a specific timeframe (e.g., one to seven days).

Dietary assessment instruments: Each instrument has strengths and limitations concerning recall bias, accuracy, quantitative detail, participant burden, and cost.
Food frequency questionnaires: A self-reporting approach capturing the frequency of food intake over a period.

Technique 1: Intake from the moment the study participant woke up until the current moment.
Technique 2: Intake from midnight to midnight the previous day.
Interviewer support: Provides portion size estimates, prompts for memory aid, checks for omissions or errors in assessment.
Additional limitations for all methods : High level of intra-individual variability. Variability within individual. The number of days to track intake (i.e. one or seven). Individual characteristics within a population (e.g. age, health status or any condition). Nutrients of interest; sample size. Degree of within/between variability.