Estimating and Assessing Nutritional Status and Intake Flashcards
Methods of estimating usual dietary intake
- direct observation
- food records or diaries
- 24hr recalls
- FFQ
Two Types of self-report instruments
short term ⇒ 24hr recalls, food records, diaries
long term ⇒ FFQ
- often used in large cohort or case-control studies to examine diet-health relationships
Food Diaries / Records
Variations in Approach
- weighted record ⇒ quantitative
- estimated food diary/record ⇒ semiquantitative
- trained/untrained respondents
- detailed review or not
- highly standardized coding rules or not
- development of electronic methods
Strengths of Food Records
- intake is quantified, detailed
- can include weekends
- could be accurate with detail and training
- data is rich in details - nutrients, cooking practices, frequency of meals and eating
Limitations of Food Records
- recording influences diet (reactive tool)
- requires literacy
- high burden
- multiple days required for usual intake
- sample selection bias
- completion worse over time
- underreporting is typical
24 Hour Recall
- amounts and foods consumed in 24 hour period prior to interview
24 Hour Recall
Variations in Approach
- training of interviewer
- standardized probing questions
- computer vs paper administration
- in person or telephone
- portion size or measurement aids
- nutrient database used
Strengths of 24 hour recalls
- low respondent burden and high compliance
- illiterate appropriate
- standardized protocol can be used
- unlikely to interfere with dietary behaviour
- large numbers of subjects
- possible to get details
Limitations of 24 hour recalls
- memory
- portion size estimation
- multiple days required for usual intake - recall is just a snapshot
- costly / highly trained
- underreporting typical
FFQ
variations in approach
- number of foods, clarity of questions
- portion size questions - pictures vs text description
- time frame
- development of food list - database
- type of administration
- supplement intake
- population of interest
- food preparation
FFQ Strengths
- large number of people
- estimates usual intake
- does not affect eating behaviour
- low cost
FFQ Limitations
- lacks detail ⇒ finite food list, details lost
- requires literacy
- affected by recent diet
- severe measurement error
- designed for different reasons
- different populations respond differently
- problems with food in composition
Assessing FFQ
What was the original purpose?
Who was the target population? Are they suitable for other locations or populations?
When was it developed? Are the foods and sizes still relevant?
Has previous validation been carried out?
Some important items to note when reading literature
- what database was used
- are valid estimations possible?
- is the correct level of precision reported?
Assessing Nutritional Status
- intake and expenditure
- anthropometric
- clinical and physical findings
- biochemical data and medical tests
- behavioural and psychological contact
Dietary and Energy Expenditure
- food and nutrient intake
- medication. herbal supplementation
- alcohol intake
- caffeine intake
- food and supplies availability
- PA
Anthropometric Measurements
- hight, weight, BMI
- growth pattern indices/percentile ranks
- weight history
- body composition ⇒ skin folds, circumferences, DEXA, Bod Pod
Biochemical Data and Medical Tests
blood and urine values reflect biological response to intake
lab data ⇒ protein, lipid, glucose profiles
medical tests ⇒ RMR, gastric emptying time, swallow study
Clinical Physical Findings
- blood pressure and heart rate
- muscle and fat wasting (temple and clavicle)
- skin (pressure ulcers)
- hair (brittle, loss)
- functional assessment of cognitive and psychological function
Behavioural and Psychological Context
- personal history (age, gender, ethnicity, education)
- past medical history
- social history (living situations, social sport, geographical, stress, occupation, religion)
