Nutrition and Diet Flashcards

1
Q

Define ‘diet’.

A

The type and amount of food and drinks that a person consumes regularly.

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2
Q

What are individual dietary recommendations based on?

A

Age
* Gender
* Physiological status (such as pregnancy)
* Weight/Height
* Physical activity
* Health status etc.

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3
Q

What are dietary reference values (DRVs)?

A

A set of estimated nutrient requirements for healthy populations in the UK.

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4
Q

What are DRVs used for?

A

To inform public health policies, food labelling, and
dietary advice given by healthcare professionals.

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5
Q

Define Reference Nutrient Intakes (RNI).

A

Levels of nutrients that are sufficient to meet the needs of almost all (97.5%) individuals in the population.

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6
Q

Define Estimated Average Requirements (EAR).

A

Levels of nutrients that are estimated to meet the needs of half of the population.

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7
Q

Define Lower Reference Nutrient Intakes (LRNI).

A

Levels of nutrients that are sufficient for only a small
percentage of the population (2.5%).

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8
Q

Define ‘Safe Intake’.

A

Level of nutrients that is considered safe for most people to consume.

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9
Q

What are the public health reasons for measuring people’s diets?

A
  • To evaluate/monitor the adequacy of people’s diets (nationally or locally)
  • To evaluate/monitor a dietary improvement programme
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10
Q

What are the research reasons for measuring people’s diets?

A

To identify any relationships between diet and health, wellbeing or disease using large population
studies.

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11
Q

What are the clinical reasons for measuring people’s diets?

A

To help diagnose a diet-related condition.

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12
Q

What are the commercial/economic reasons for measuring people’s diets?

A

To assess consumer choice of foods

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13
Q

List the 2 approaches to measuring diet and nutrition.

A
  • Measure dietary intake
  • Measure nutritional status
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14
Q

How do you measure nutritional status ?

A

Using biomarkers via blood, urine etc.

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15
Q

What is the purpose of measuring dietary intake?

A

Evaluate type and quantity of foods consumed and
identify levels of nutrient intakes.

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16
Q

What is the purpose of measuring nutritional status?

A

To identify the levels of a nutrient in a person’s body.

17
Q

Give an example of a direct method of measuring diet and nutrition.

A

Directly measure food intake by individuals (can be
households).

18
Q

Give an example of an indirect method of measuring diet and nutrition.

A

Estimate intake by using information on food
availability (can be at national, regional or household level (not individual).

19
Q

Define ‘biomarker’.

A

Substance found in the body that can be used to measure physiological processes and reflect changes in a person’s health status.

20
Q

Give two examples of biomarkers.

A
  • Blood levels of vitamin D
  • Urine to measure sodium
21
Q

Give examples of objective methods to assess dietary intakes.

A

Direct observation, duplicated diets (biomarkers)

22
Q

Give examples of subjective methods to assess dietary intakes.

A
  • Weighed food diaries
  • 24 hour recall
  • Food frequency questionnaire
23
Q

List a few strengths of prospective food diaries.

A
  • Provides detailed descriptions of all foods and drinks.
  • Food / drink recorded at time of consumption, so no recall error.
  • If weighed, portion sizes exact.
  • All eating occasions covered.
  • Good for capturing foods eaten frequently
  • Excellent estimates multiple levels; for energy, nutrients, food and food groups and overall diet.
24
Q

List a few weaknesses of prospective food diaries.

A
  • Can be time consuming and labour intensive. Very costly in staff time.
  • Large respondent burden - individuals must be
    motivated, compliant, numerate and literate.
  • The individual may alter his/her diet to make it easier to record. Intake recorded may not be ‘typical’ diet.
  • Weighing food eaten away from home can be difficult
  • Foods eaten less than once or twice a week may not be
    captured.
  • If 7 days, recording can become less accurate towards
    the end of the period because of study fatigue.
25
Q

List a few strengths of 24 hour recall method.

A
  • Provides detailed descriptions of all foods and drinks.
  • Can estimates multiple levels; for energy, nutrients, food and food groups and overall diet for a large group.
  • Respondent burden is relatively low.
  • Can be relatively quick.
  • Recall does not alter food intake pattern but may introduce recall bias.
  • Literacy not required if interviewer administered.
  • Can be repeated e.g. 3 separate 24h recalls to give better idea of habitual intake
26
Q

List a few weaknesses of 24 hour recall method.

A
  • Single 24 hour recall not representative of habitual individual intake but may be useful for group means.
  • Method is reliant on memory and developed cognitive skills.
  • Recall bias
  • Conscious: recall healthier foods, ignore unhealthy snacks
  • Expensive to administer due to high interviewer burden
  • Repeat 24-hour recalls increase time and cost of analysis.
27
Q

List a few strengths of food frequency questionnaires.

A
  • Assess habitual consumption over an extended period of time
  • Comparatively easy to administer
  • Low cost
  • May be self administered via mail or phone/online.
  • Can gather information on a range of foods or be shorter and focus on specific foods / nutrients.
  • Portion size estimates can be used to obtain absolute nutrient intakes.
  • Data can be analysed relatively quickly.
  • Computer-readable forms can be scanned into computers reducing data-entry errors.
28
Q

List a few weaknesses of food frequency questionnaires.

A
  • The list can never include all foods.
  • Accurate reporting relies on respondent’s memory.
  • May be bias due to differential under- or over- reporting.
  • Requires literacy and numeracy skills.
  • Estimating portion sizes accurately can be difficult.
  • May not be completed fully.
  • Food list may not reflect eating habits of all sub-populationq
29
Q

List a few examples of new technologies that are used for dietary assessments.

A
  • Wearable devices
  • Smartphones apps
  • Digital photography
30
Q

List a few advantages of new technologies that are used for dietary assessments.

A
  • Can be used irrespective of time or location.
    ✓ More opportunity for real time data collection.
    ✓ Possibility to reduce measurement error – larger food databases or pictures to aid portion size calculations.
    ✓ Lower participant burden (often faster to complete).
    ✓ Reduced data processing – some opportunity for automated nutrient assessment.
    ✓ Some participants report preference for innovative techniques.
31
Q

List a few disadvantages of new technologies that are used for dietary assessments.

A
  • Recall Bias – many techniques still rely on individuals to remember their intake correctly.
  • Performance Bias – Individuals are still likely to change their diet over assessment period using methods that rely on real time data collection.
  • Social Desirability Bias – Individuals may misreport their intake to be more desirable.
  • Measurement Error – although this can be greatly improved, there is likely to be some measurement error, and this is likely to vary between technologies.
  • Have not always been validated.
32
Q

Write the formula for estimated value.

A

Estimated Value = True Value + Total Error

33
Q

What type of study design is the National Diet and Nutrition Survey (NDNS)?

A

Continuous cross-sectional survey

34
Q

When did the NDNS begin?

A

Began in 1992 but became a continuous program in 2008.

35
Q

What is the purpose of the NDNS?

A

To collect detailed information about food consumption, nutrient intake and nutritional status of the general population aged 1.5 years and older living in private households in the UK.

36
Q

What was the dietary assessment method used in the NDNS?

A
  • Up to 2008: Weighted 7-day diet diary / 24-hour recall
  • Between 2008-2018: Paper based 4-day estimated diary
  • 2019 onwards: online 24-hour recall (Intake24)
  • Biomarkers also collected
37
Q

What type of study design is the National Survey of Health and Development (NSHD)?

A

Longitudinal birth cohort

38
Q

What kind of participants were used in the NSHD?

A

All participants born in the same week of 1946.

39
Q

What were the dietary assessment methods used in the NSHD?

A
  • 24-hour recall in 1950, 1982 and 1989
  • 5-day estimated food diary in 1982, 1989, 1999, 2006-2009