Lecture 5 - Dietary Assessment Flashcards
What are the steps to evaluate the diet?
- Information on dietary intake
- Quantification of energy & nutrient intake
- Evaluation of diet adequacy
What information can you gather from a dietary intake?
Food quantity and quality Variety Resources to get food Preferences Dietary Supplements Medication
What factors influence food intake?
Heath Status
Food availability
Food Selection & Preparation abilityies
Eating pattern/lifestyle habits
Culture/Ethnicity & Religion
Education & Experience on healthy eating
Community/Political/Socio economic
Dietary restrictions
-all have an impact on dietary beliefs & habits
What are the 5 dietary assessment methods?
24hr recall Food Frequency Questionnaire Food Records Direct Observation Diet History
What is the 24hr recall?
Tool asking individuals about their intake of food and beverages during the previous 24hr
- retrospective
- ask if its typical/usual intake
How do you start a 24hr recall/
Asking what they first ate or drank when they woke up
What are advantages of 24hr recall?
Fast to administer Low Cost Minimally Burdensome for client Client does not need to read and write Only a small influences in changing the dietary behaviour reported by client -with competent interviewer
What are the limitations of 24hr recall?
Relies on memory
Tends to overestimate low consumption and underestimate high consumption
High variation among interviewers
Necessary to conduct more than once to estimate AVERAGE intake
Interviewer should be competent and experienced
Interviewer should be standardized and follow a protocol to reduce variability
What is a food frequency questionnaire?
Asking individuals to complete a survey of their food and beverage intake over a period of time
- reetrospective
- include food/beverage list and consumption frequency
- non-quantitative/semi-quantative/ quantiotative
Who administers food frequency interview?
By interviewer or see administered
-most used in large survey
What are the advantages of FFQ?
Minimally burdensome for patient Fast to administer Low Cost Reflects casual consumption of patient Allow to look at intake of particular nutrient
What are the limitations of FFQ?
Gives mostly qualitative data (food type)
Relies on patient recalling info
Requires patient to be able to read and write
Mentally harder for patient to answer (recall up to 1 year)
-Q’s about intake not related to meals
What is a food intake record?
Asking individuals to record their food and beveage intake over a certain number of days
- Retrospective/prospective
- Some ask to weigh food to record
What are the advantages of FI?
Does not rely on patient recalling all info
Reflect usual consumption of patient
More precise than 24hr recall, because accuracy increased with # of days
Including a weekend day accounts for a possible change of eating behaviour on weekends
What are the limitations of FI?
Highly burdensome for patient
Patient Musy ne able to read and write
Patient may modify pattern of intake (relies on honesty)
Patient frequently do not provide specific info
What is direct observation?
Directly looking at an individuals food/beverage selection intake and eating behaviour
- prospective tool
- qualitartive and quantitative
What are the advantages of direct observation?
Not burdensome for patient
Does not rely on memory
Not necessary for patient to read and write
What are the limitations to direct observation?
Burdensome for RD/nutritionist
Can be invasive
May be difficult to get all info
Does not reflect usual consumption (unless done in a home care environment)
What is a diet history?
Complete profile of dietary intake of an individual collected by skilled nutritionist during interview using a combo of data collection methods
- 24hr recall
- FFQ
- FIR
What kind o questions are asked in a diet history?
Probing Q asked to get a good picture of overall dietary habits
- allergies
- changes
- supplements
What are the advantages of diet history?
Fairly complete and detailed description of intake (qualitative and quantitative)
More accurate than 24hr, FFQ or FIR
Makes up for daily and seasonal variations
What are the limitations of the diet history?
Time consuming (only get 15-30 for everything)
RD/nutritionist should be competent and experiences
Interview should be standardized
Mostly relies on patient recalling info
More $ to administer and analyze
What are the items that are more commonly underreported?
Energy intake more frequent in females and overweight people
Snacks, sweets, desserts in obese
Alcohol in heavy drinkers
Among those not following their diet Rx
Who is likely to over report things??
people with Anorexia nervosa
In people doing a diet report, what are the things they write that a re not accurate?
Write what they think the interviewer wishes them to eat
Reporting desirable intake
Missing and Phantom foods
What is the difference between missing and phantom foods?
Missing= food eaten but not reported (snacks, alcohol, coffee, bread)
Phantom= Food not eaten but reported (veggies and fruit)
What is the best way to evaluate usual nutrient intake?
Diet should be measured for multiple days, including days and weekends
What does the # of days depend on when evaluating nutrient intake?
Nutrient of interest
Individuals/groups studied
Degree of inter-individual variation in nutrient intake
Desired degree of measurement precision
Which nutrient requries the most number of days to get an accurate estimate?
Vitamin A
-micro nutrients tak emoe days to analyze because there is a higher variance of micronutrients in food
How can we help patients in estimating serving size?
Use of food models
Sales
Serving size aids
Photographs
What are the 2 limitations in dietary assessments?
Interview should trained and follow a similar standard protocol
Limitation of nutrient comp takes and databases
- data not available
- errors
- lack of analytical sensitivity of lab tests to measure small quantities of nutrients
For sizing what does your palm, fist, thumb and thumb tip equal to?
Palm - 3oz
Fist - 1 cup
Thumb - 1-2 tablespoons
Thumb tip - 1 teaspoon
When doing a 24hr recall what kind of questions should you use?
Using neutral questions
-then can prob for more specific info like where and when
What is the standard protocolar 24hr recall?
Use aids for serving size estimation
Ask about food group missing and supplements
Ask if typical dat (if not why)
Ask if they eat differently on weekends (is yes, then why)
What is an easting behaviour diary?
Food intake record also including info related to eating behaviour
- degree of hunger/thirst
- Reason for choices
- number of helping
- degree of satiation
- feelings associated with eating/drinking
What are some tools used to quantify energy and nutrient intake?
Exchange lists
Food Comp tables
Food analysis software
What is the most popular food analysis software and some facts about it?
ESHA
- origin in salem Oregon in 1984
- over 72,000 foods
- 172 nutrient components
- 700 for 1 licence
Are food analysis software available on the internet?
Yes but not as good because:
- slower
- harder to use
- editing more dificult
- Dont allow nutrient analysis for several days
- Fewer foods and nutrients
- no social features
- lack adequate help function
What is the %. daily value?
DV for vitamins and minerals based on 1983 recommended nutrient intakes for Canadians and representatives the highest recommended intake for each sex and age
what re the limitations to the DV?
Alot has changed since 1983
Based on Sedentary lifestyle
Certain people need more or less than 2000 cals
How do you evaluate diet adequacy?
By comparison to requirements set by Food guide or Dietary reference intakes (DRI)
What reference do we use to measure energy?
Estimated energy requirement
What reference do we use to measure macronutrients?
Acceptable Macronutrient Distribution Range (AMDR)
What reference dow e use to measure other nutrients?
Adequate intake (AI)
Tolerable Upper Intake Level (UL)
Estimated Average Requirement (EAR)
Recommended Dietary Allowance (RDA)
What are some factors that influence measurements?
Bioavialability Drugs Alcohol Smoking Age Gender Ethnicity Disease
How to we interpret DRI for individuals?
Intake can be assessed qualitativly or quantitatively
Qualitative may suffice depending on purpose
Quantitative assessment need accurate dietary data, correct DRI and interpret results appropriately
When applying DRIs what 2 distributions do they use?
Requirement distribution
- EAR
- RDA
Intake distribution
-Observed or reported nutrient intakes
What is the difference between individual EAR and Group EAR?
Individual
- probability of inadequacy: outcome of comparison between individual usual intake to corresponding life stage distribution of requirements. Probability that intake does not meet requirements
- Probability of inadequacy
Group
-Prevalence of inadequacy- % of group with intakes below requirements
What is better statistically for the graph, 1 day or lots of days of observations?
Lots because you will be more accurate and it will give you more of a bell shaped curve
What is the interpretation if the z-score is positive or negative?
+ means you have a probability of an adequate diet
- probability go an inadequate diet
What happens when you use a z score for AI instead of EAR?
z score is less certain
What can you conclude if you have a z score with AI and intake is higher than the AI?
Consumption is alsmost certainly going to be adequate
if intake is less than AI, no conclusion can be drawn
When using UL to asses individuals, what does it apply to?
Only to intakes form supplements, fortificants or medications
-Similar to AI if intake is below= inconclusive
What are other sources of information about nutrient intake and assessment?
Biochemical measurements
Healthy lifestyle factors
Anthropometric measurements
What should you recommend/plan to do for patients so they meet the values they are supposed to be consuming?
Meet RDA or AI to minimize risk of inadequacy for gender/age/classification (pregnancy)
How do you evaluate dietary needs for groups?
RDA not appropriate
Variabiity between and within gorups
EAR method:
- probability
- EAR cut-point method
What is the probability approach for groups?
Determine the risk of inadequacy for each individual in the population then averaging individual probabilities across the group
What are the validity conditions in group testing?
Intakes and requirements are independent of each other
Distribution of requirements is symmetrical around the EAR
Distribution of intakes has greater variability than the distribution of requirements
In assessing groups, what do you do with nutrients with an EAR?
% with usual intake < EAR approximates prevalence of inadequatcy
In assessing groups, what do you do with nutrients with an AI?
Group with mean intake> AI likely at low risk
-no conclusions if mean intake is
In assessing groups, what do you do with nutrients with an UL?
% with usual intake > UL at potential risk
In planning for groups what must you consider about the group?
Homogenous or mix of people Group stable or stressed Vulnerable subgroups If needs are similar, use EAR and adjust upward if need be Consider. UL to about risk
