2E Behaviour

Question 1

What is nutrition?

Answer 1

The process of securing the dietary requirements of an individual or of a population

Question 2

What are macronutrients and micronutrients?

Answer 2

Macronutrients - required in comparatively large amounts e.g. fat, carbohydrate, protein, water

Micronutrients - required in small amounts e.g. minerals and vitamins

Question 3

What are different ways of gathering nutritional surveillance data?

Wants some more general points + UK specific examples

Answer 3

Food supply data
- Food production and imports/exports (conducted by UN)
- Ad hoc food mapping may also be done e.g. to identify food deserts

Food expenditure surveys
- E.g. ONS Living Costs and Food Survey

Diet and nutrition surveys
- Food diaries can be biased as overweight people more likely to underestimate food intake

Nutritional surveillance in children
- Breastfeeding: Infant feeding survey
- Proportion of children eating school meals
- National Child Measurement Programme

Study designs to assess nutrition
- Ecological (potential for confounding and ecological fallacy)
- Case-control (recall bias)
- Cohort
- RCTs (very expensive, effect sizes tend to be small for diet so may need meta-analysis)

Question 4

Short term nutritional problems

Answer 4

Sugar –> dental caries
Low salt –> hypotension
Low protein –> Kwashiorkor (muscle wasting, protruding abdomen, fatigue, diarrhoea)
Low protein and calories –> marasmus (emaciation)
Low Vit C –> Scurvy (gum disease, bleeding, listlessness)
Low Vit B1 –> Beriberi (heart failure, generalised oedema, neuropathy)
Low Vit D in children –> Osteomalacia and rickets
Low Vit D in adults –> Osteoporosis
Low folate –> Anaemia, neural tube defects
Iron deficiency –> Anaemia

Question 5

Long term nutritional problems

Answer 5

Central obesity –> T2DM
Low fruit and veg –> CHD and some cancers
Low Ca –> osteoporosis

Question 6

What is malnutrition?

Answer 6

A lack or excess of any component of the diet

Question 7

What are the impacts of malnutrition in pregnancy?

Answer 7

Leads to IUGR which is associated with stillbirth, CLD, hypoxic brain injury. Can also lead to long-term impacts e.g. CVD, renal disease, impaired cognitive development.

Question 8

What are the impacts of malnutrition on disease aetiology?

Answer 8

• Increased risk of infections
• Impaired wound healing
• Organ failure

NB Disease can also cause malnutrition: illness –> reduced appetite –> worsened malnutrition

Question 9

What are the impacts of malnutrition on growth and development

Answer 9

Acute malnutrition can lead to children being underweight and to wasting

Chronic malnutrition can also lead to underweight and to stunting

Question 10

What are the different markers of nutritional status?

Answer 10

Anthropometry
- BMI
- Growth charts (height and weight)
- Head circumference in infants
- Skinfold thickness

Indices of malnutrition
- Malnutrition Universal Screening Tool (MUST)

Biochemical tests
- Plasma fatty acids
- Urinary sodium
- Urinary nitrogen (marker of protein)

Bioelectrical impedance
- Measuring body composition

Imaging
- Infrared or X-rays for body fat percentage

Food consumption surveys
- Ask about food intake
- Duplicate diet method: people weigh out two portions of their meal and one is sent to chemical analysis

Question 11

What are examples of nutritional interventions?

Answer 11

• Fortification of foods e.g. folic acid in flour
• Fluoridation of water
• Workplace/school campaigns for healthier foods to be available
• Media e.g. TV shows on healthy eating
• Collaboration with industry e.g. supermarkets and food manufacturers (evidence weak that this changes industry practice or improves population health)
• Free fruit in schools

Question 12

How can you measure the impact of nutritional interventions?

Answer 12

• Food sales
• Food surveys re diet
• Clinical markers e.g. growth, BMI, BP, dental caries
• Biochemical markers e.g. cholesterol, urinary sodium
• Morbidity and mortality
• Psychological indicators e.g. self-esteem

Question 13

What are the different determinants of dietary choices?

Answer 13

Social determinants
- Poverty
- Culture
- Education

Behavioural determinants
- Attitudes and beliefs
- Psychological e.g. mood and stress

Question 14

What are different dietary reference values (DRVs)

Answer 14

Estimated average requirement (EAR): Average amount needed by a group (i.e. 50% of people’s requirements are met)

Reference nutrient intake (RNI): Amount that meets needs of 97.5% of the group (meets need of vast majority)

Lower reference nutrient intake (LRNI): Amount that meets needs of 2.5% (most will need more)

Safe intake: Issued when insufficient evidence for EAR, RNI and LRNI

Question 15

What is the evidence for nutritional recommendations?

Answer 15

Some evidence is ecological e.g.
- Intersalt demonstrated salt linked to BP
- Seven Countries demonstrated links between heart disease and dietary fat

Question 16

Health effects of recreational drugs

Answer 16

• Mental health e.g. anxiety, depression, psychosis
• Mortality
• BBV
• Poor nutrition
• Not health but: unemployment, homelessness, crime

Question 17

What are different types of diets and their health effects?

Answer 17

Western diet
- High total energy –> obesity
- High saturated fats (butter, red meat) –> obesity, CVD, cancers
- Low fibre –> Colorectal cancer
- High salt –> CVD

Mediterranean diet
- High unsaturated fats (olive oil) –> low cholesterol and CVD risk
- High fruit and veg and less red meat –> lower cancer risk and obesity

South Asian diet
- High saturated fats –> Obesity, CVD
- High fruit and veg
? - High carb –> T2DM (this is just my idea)

Question 18

What are the different approaches that can be applied to complex issue such as diet, alcohol, smoking etc?

Answer 18

Medical approach
- Prevention is focussed on risk factors and pharmacological interventions

Socioenvironmental approach
- Recognised the role of structural factors e.g. social, political and economic environment
- A: evidence of effectiveness e.g. legislation on salt in food; may help to reduce inequalities
- D: “nanny state” critique by libertarians

Behavioural approach
- Focussed on individual choice and education
- May use social marketing approaches
- Limitations: ignores structural, social and cultural factors

Question 19

Advantages and disadvantages of “Nudge” theory

Answer 19

Adv:
- Does not restrict individual choice
- Low cost
- Simple and rapid
- Some evidence of effectiveness

Disadvantages:
- Ill-defined
- Little large scale evidence
- Arguably less effective than legislation
- May widen inequalities