Lecture 1 + 2 + 3 Flashcards
(15 cards)
What is the law for updating the US dietary guidelines?
They have to be updated every 5 years to keep up with the evidence
What are 2 changes in the US dietary guidelines from 2020 to 2025
- Greater focus on eating patterns (not just food and nutrients)
- Greater focus on guidelines as not a rigid prescription but an adaptable framework in which individuals can enjoy foods that meet their personal, cultural, and traditional preferences and fit within their budget
What are 4 overarching US dietary guidelines
- Follow a healthy dietary pattern at every stage in life
- Customize and enjoy nutrient-dense food and beverage choices te reflect personal preference, culture and budget
- Focus on meeting food group needs with nutrient-dense food/beverages, stay within calorie limits
- Limit food/beverages higher in added sugars, saturated fat and sodium and limit alcohol
What are 5 key principles of the Brazilian dietary guidelines
- Diet is more than intake of nutrients
- Dietary recommendations need to be tuned to their times
- Healthy diets derive from socially and environmentally sustainable food systems
- Different sources of knowledge inform sound dietary advice
- Dietary guidelines broaden autonomy in food choices
What are 10 steps to the Brazilian dietary guidelines
- Make naturally or minimally processed foods the basis of your diet
- Use oils, fats, salt and sugar in small amounts when seasoning or cooking
- Limit consumption of processed foods
- Avoid consumption of ultra-processed foods
- Eat regularly and carefully in appropriate environments and in company
- Shop in places that offer a variety of naturally or minimally processed foods
- Develop, exercise and share cooking skills
- Plan your time to make food and eating more important in your life
- Out of home, prefer places that serve freshly made meals
- Be ware of food advertising and marketing
What are Nutrient Reference Values (NRFs)
= A system of reference values to identify the average requirements for nutrients needed by individuals
What are the 7 NRVs used in NZ
- Estimated average requirement (EAR) = Daily average nutrient level estimated to meet the requirements of half the healthy individuals in a particular life stage and gender group.
- Recommended Dietary Intake (RDI) = Daily nutrient level sufficient to meet the requirementsof nearly all (97-98%) healthy individuals in a particular life stage and gender group.
- Adequate Intake (AI) = Daily average nutrient level based on observed or experimentally-determined approximations or estimates from a group or groups of healthy people.
- Estimated Energy Requirement (EER) = Average energy intake predicted to maintain energy balance in a healthy adult of defined age, gender, height, and level of physical activity.
- Upper Level of Intake (UL) = Highest nutrient level likely to pose no adverse health effects to almost all individuals in a population.
- Acceptable Macronutrient Distribution Range (AMDR) = Estimate of a range of intake for each macronutrient for individuals expressed as a % of energy intake to maximise general health.
- Suggested Dietary Target (SDT) = Daily intake from food and beverages for certain nutrients that may help in prevention of chronic disease.
Explain the difference between RDI and EAR and the formula for calculating the RDI
The RDI covers the needs of most people, so if this is good then most people will meet the nutrient requirements, and it is mostly used for individuals. The EAR covers the needs of half the populations, so if this is good then half of the people will meet the requirements, and the other half won’t, and it is mostly used for groups.
The formula for the RDI is:
RDI = EAR + 2*SD(EAR)
What are 4 types of studies and their strengths and limitations?
-
Ecological = Examine relationships, generate hypothesis
Strengths:
- Information is quick and rapid
- Does not require recruitment of people
Limitations:
- Confounding
- Limitations of data sources -
Case control = Compare diets of those with the disease to without the disease
Strengths:
- Information is quick and rapid
- Useful if rare disease
- Efficient, requires a small sample
- Low attrition as low demand on subjects
Limitations:
- Poor memory of past diet
- Difficult to isolate one component of diet
- Confounding
- Need to carefully match controls -
Cohort = Observe population over time to study
relationship between diet and disease
Strengths:
- Dietary information is collected before the disease
- Can identify other patterns
Limitations:
- Expensive
- Time consuming
- Need large numbers of people -
Experimental = Test relationship between diet and
disease, can explain causation
Strengths:
- Most rigorous evaluation of dietary hypothesis
- High internal validity
Limitations:
- Complexity of diets
- Time change between exposure and outcome is usually long
- Compliance with trial diet
- Enrolment bias
- Expensive
What are the objectives of dietary assessment?
- It provides information about dietary intake patterns.
- It also provides information about estimated nutrient intakes.
- It is helpful in planning health education activities.
- It also provides information about food habits and attitudes.
What are 4 dietary assessment methods and their strengths/weaknesses?
-
Food records = Respondent records all foods and beverages consumed over a period of 3-7 days with weighed or estimated portion size (7 days is gold standard); reporting should be at the time of consumption; generally used for adults
Strengths:
- Foods are recorded as consumed
- Brand, type, labels or menus can be used for information
- Improves quality of dietary data
- Foods can be weighed to accurately record quantities
- Prospective, thus not reliant on memory?
Weaknesses:
- Non-response bias
- Participants must be literate
- Respondent bias (changing behaviour due to recording process)
- High participants burden -
24-Hour recall method = Participant is asked to report all the foods and beverages consumed for the previous day; structured method with probes; can be repeated to estimate average food intake over longer periods
Strengths:
- Assesses actual dietary intake of individual
- Repeat 24h recalls for more accurate data
- Low participant burden
- Diet recorded after food consumption (less likely to change behaviour)
- Can be standardised and automated using software
Weaknesses:
- Respondent biases
- Interviewer biases (different techniques to probe info etc)
- Incorrect portion size (hard to judge)
- Only assesses dietary intake for one day
- Diets vary day-to-day
- Only suitable for group data -
Food frequency questionnaire = Report on frequency that specific foods are consumed and their quantity; often used to study diet-disease relationships
Strengths:
- Better measure of habitual food consumption and dietary patterns
- Can be used to identify gross changes or differences in usual dietary intake
- Can be self-administered
- Low participant burden
- Reduced research costs
Weaknesses:
- Respondent biases
- Memory lapses
- Many detail of intake not recorded (brands, types, cooking method, hard to assess serving sizes, etc) - Diet History
What are 6 sources of error in dietary assessment?
- Non-response bias
- Respondent bias: social desirability, forgetting to report, etc
- Interviewer bias: different techniques for probing info
- Incorrect portion size: failing to report correctly, misconceptions of what is meant with a certain size
- Supplement use: supplements can be easily omitted/missing details
- Coding errors: errors that arise when converting foods into nutrients
What are national nutrition surveys?
= Typically ascertain the overall nutritional status of a population by means of a cross- sectional survey
- Provide a snapshot of the dietary issues for the population at a particular time
- Can identify and describe population subgroups “at risk” for chronic nutrition issues
- Generate information that can be used to allocate resources and formulate policies
What does dietary assessment look like in research?
- Prospective (cohort) studies
- Exposures of interest are assessed at baseline and disease outcomes occurring over time are compared to baseline
What are 4 limitations of the current methods?
- Measurement error: Underreporting of energy intake
- High burden: User-initiated
- Self-reported: Subjective
- Rely on memory
