Week 2 - Measuring Food Intake + Food Behaviours Flashcards
Nutrition assessment
- Cornerstone of nutrition sciences
- Allows investigation and interpretation of relationships between diet and disease
- Allows for assessment of individual and population nutrition status
- Important to determine the likelihood of a nutrient deficiency
- Establishes nature and aetiology (the cause) of a problem
- In a community it identifies the extent and distribution of the problem
- To identify associated environmental factors
- Helps institute preventative programs
4 parts of nutritional assessment
Anthropometric
Biochemical
Clinical
Dietary
Anthropometric assessment
- Height, weight, waist circumference, hip circumference, skinfolds
- Important to establish weight status, BMI and waist to hip ratio
- Important to monitor overtime
- Taken periodically
- Compared to previous measures or standards specific to age/gender
- Does not indicate anything about nutrients
- May give indication to a nutrient deficiency/excess
- Are variable person to person
- Can be taken reliably, easily and accurately
- Useful when there is a chronic imbalance in one’s diet
BMI
- Evaluation of bodyweight considering height
- Has many limitations as it does not consider body composition
- Those who are elderly or with a physical disability may have muscle wastage and therefore are considered an exception
Weight(kg) / height (m2)
Biochemical assessment
- Includes blood tests, urine samples
- Used to assess body stores
- Levels are compared to normal values for a similar population
- Important for detection of nutrient deficiency
- Uncovers early signs before symptoms appear
- Can also confirm other suspicions
Clinical assessment
- The use of a number of physical signs that are known to be associated with malnutrition and deficiencies
Types of dietary recall
24 hour dietary recall
Food frequency questionnaire
Food record
Diet history
24 hour dietary recall
- Recalling intake of the past 24 hours
- Can establish a recent food pattern if repeated regularly
- Useful for large populations for a mean intake
- Weekends and weekdays
- First pass; list all food and drink consumed
- Second pass; detailed description of each food (brand, cooking method)
- Third pass; estimate amount of food consumed
- Fourth pass; recall is reviewed and supplements added if any
Strengths of 24 hour dietary recall
- Quick
- Can be used with illiterate subjects
- Only short term memory recall
- Short interview length
Limitations of 24 hour recall
- Relies on memory
- Subject to bias
- Need trained interviewers
- Can be expensive of collected via interview
- Doesn’t show variation in the diet
Food frequency questionnaire
- List of foods (general or specific)
- Measures frequency at which groups of foods are consumed during a certain time period
- Can be used to predict intakes of certain nutrients or non-nutrients
- Ascertains the mean nutrient intake of a group
Strengths of FFQ
- Low burden
- Easy to process and collect results
- Can be standardised
inexpensive
Limitations of FFQ
- List may not contain all foods
- Seasonality
- Validity and feasibility not clearly established
- Literacy and numeracy skills needed
- Specific to a population
Food record
- Estimated food record or weighed food record
- Ranges from 1-7 days
- The greater the number of days the greater the accuracy, but can discourage participation
- Usually only used in research
Estimated food record
- Not reliant on memory
- Measure and write all things consumed
- Brand names and method of cooking included
- Mixed dishes are complex
Increases accuracy
Weighed food record
- Weigh and write down food (using scale)
- Most precise level available
- Brand names, prep included
- Mixed dishes are complex
- Burdensome
Strengths of food record
- Gold standard
- Assess current diet as consumed
- Precision of portion sizes
Limitations of food record
- Underreporting
- High burden
- Literacy and numeracy skills required
- Habitual eating patterns may change
- Requires multiple records to be accurate
Diet history
- Estimates food intake and meal patterns over a long period of time
- Includes; interview, questionnaire and a home record for 3 days
- Combines pattern of intake with specific nutrient information
Strengths of diet history
- Comprehensive information can be obtained about portions and cooking methods
- Employed in clinical practices
- Useful to identify a usual intake
Limitations of dietary intake
- Expensive
- Unsuitable for large population
- Biased
- No standardised method
- Time consuming
- Insufficient quantitative value
Feasibility
Determines how realistic results are
Food databases
Will give specific nutrient breakdowns of each food
Behaviour definition
The action or reaction of an organism, usually in relation to the environment
Food definition
Any substance, usually composed primarily of carbohydrates, fats, water and/or proteins, that can be eaten or drunk by an animals for nutrition or pleasure
Food behaviour
- At a basic level it includes; buying, eating and drinking
- Assessed by biologists (physiological), psychologists (objectivity), sociologists (social influences), anthropologists (cultural interactions) and political scientists (globalisation)
Food behaviour decisions
- What options are available right now?
- Appeal
- Familiarity
- Taste
- Health
- Time
- Money
- Social influence
Terminology
Satiety Disinhibition Emotionality Externality Satiation Passive overeating Conditioned taste aversion
Observational study designs
Investigation of behaviour with no intervention Ecological Cross sectional Case control Cohort
Ecological
- investigates exposures and health outcomes at the group level
- Cross country comparisons
- Migrant studies
- Analysis of trends overtime
- Determine cause
- Useful for generating hypothesis
- The first step in developing a theory
Cross sectional
- A descriptive study involving the measurement of exposures and outcomes at one point in time
- Only a snapshot
- Good way to obtain information from a large group of people
Case control
- Involves individuals with disease being identified and compared to those without, the exposure of the two groups to the factor being studied are compared
- Quick to complete
- Less costly due to shorter duration and smaller sample size
Cohort
- Where a cohort of disease free people are followed overtime
- Baseline information is collected based on exposures of interest
- Participants who developed disease are identified and compared to the exposures that those who remained disease free
- Time and resource intensive
- Provide high quality evidence
Experimental study desgins
Randomised control trials
Randomised control trials
- Involves participants being assigned to the intervention group or the control group
- After the trial the results of the groups are compared
- Time consuming
- Determine effects of treatment
- Other variable are kept constant
- Is gold standard
Weakest to strongest study designs
- Ecological
- Cross sectional
- Case control
- Cohort
- Intervention (RCT)