56.3 Nutrition [Hannah]

Question 1

What subgroups within the population is vitamin D recommended for?

Answer 1

• Pregnant women
• Children under 4y/o
  
  • These two above are included as part of the Government ‘Healthy start’ supplement programme (money off supplements up to 4y/o)
• Individuals with dark skin
• Individuals with limited exposure to sunlight
  
  • E.g. not sufficient sunlight in the UK in the Winter

Question 2

What is the Healthy Start programme?

[EXTRA]

Answer 2

• Includes pregnant women or with child(ren) under 4y
• Means-tested benefit
• Voucher worth £3.10 per week (babies under 1y qualify for 2 vouchers per week) to spend with local retailers
• Vouchers which can be spent on: plain milk, plain fresh or frozen fruit and veg or infant formula milk
• Separate scheme provides Healthy Start vitamins:
  
  • For pregnant women: folic acid, vitamins C and D
  • For babies and young children (6 m to 4y): vitamins A, C and D

Question 3

What defines a vitamin D insufficiency and methods of dealing with those at risk?

Answer 3

25-hydroxyvitamin D of <25nmol/L

• At risk groups advised to take supplements
  
  • Prophylactic treatment shown to be more cost-effective than large-scale testing
• However, promotion, uptake and adherence within the population is poor

Question 4

What subgroups within the population should be taking folic acid? How much should be taken?

Answer 4

• Women trying to get pregnant
• Pregnant women
• 400mcg/d for all women planning pregnancy and during the first 12 weeks
• 500mcg/d for those at high risk

Question 5

Give an example of a study showing effect of folic acid on preventing neural tube defects.

[EXTRA]

Answer 5

Source: MRC Vitamin Study Research Group, Lancet 1991

Question 6

What are some examples of subgroups within the population that require specific vitamins?

Answer 6

• Women trying to get pregnant: folic acid
• Pregnant women: folic acid, vitamins C and D
• Children under 4y/o: vitamins A, C, D
• People with darker skin or limited exposure to sunlight: vitamin D

Question 7

What is obesity a primary risk factor of?

Answer 7

Mostly diabetes, cancer and CVD

Question 8

What are some ways of preventing diet-related disease?

[EXTRA]

Answer 8

• Achieve energy balance and a healthy weight
• Shift fat consumption away from saturated fats to unsaturated fats and towards the elimination of trans-fatty acids
• Increase consumption of fruits and vegetables, and legumes, whole grains and nuts
• Limit the intake of free sugars
• Limit salt (sodium) consumption

Question 9

Roughly how many premature deaths are averted each year due to dietary interventions in the UK?

[EXTRA]

Answer 9

• Approximately 33,000

Question 10

What are some methods of changing the food environment?

[EXTRA]

Answer 10

• Helping the population in supporting a healthy diet needs to be done on both an individual and an environmental level for the best results
• Education only has a modest effect on changing behaviour, need environmental changes also
• Reformation example: salt reduction policies by UK government, decreased salt intake by 15% in the last decade
• Zoning example: fast food restaurants have to be a certain distance away from schools
• Soft drink industry levy: 44% average reduction in sugar levels of drinks subject to the tax
  
  • Resulted in a 3% decrease in overall sugar consumption in the UK

Question 11

What are some studies showing the health benefits of fruit and vegetables?

Answer 11

• For general mortality, dose-response curve is non-linear and decreases risk as intake increases until 400g/d, after this point the relationship is weaker
  
  • Suggests that we should be eating minimum 400g/d of fruit and veg
• Weak negative association with cancer
• Relatively linear relationship with CHD
• Relatively large effect on reducing stroke risk, plateau occurs around 200g/d

Question 12

Describe the features and results of this controlled dietary intervention study.

[EXTRA]

Answer 12

• Standardised diet during run-in period
• Results showed no/little effect on insulin sensitivity
• However, there were positive effects on reducing the amount of saturated fats and lowering glycaemic index in terms of lipid profile

Question 13

What are the effects of salt reduction and increasing fruit, veg and low-fat dairy (DASH diet) on blood pressure?

[EXTRA]

Answer 13

• Diets given for 30 days
  
  • 3 different subgroups within each group, with altered salt intake
• Both reduced salt and DASH diet caused a decrease in blood pressure
  
  • Greatest effect seen when the two diets were combined

Question 14

What are the effects of riboflavin supplementation on blood pressure?

[EXTRA]

Answer 14

• Riboflavin is an essential co-factor for MTHFR
  
  • Methylenetetrahydrofolate reductase (MTHFR) is required for the formation of 5- methyltetrahydrofolate, the methyl donor in the re-methylation of homocysteine to methionine.
• The common 677C→T polymorphism in the MTHFR is associated with an increased risk of hypertension and CVD, especially stroke.
• Participants randomised within each genotype group to receive 1.6 mg per day riboflavin or placebo for 16 weeks, n=181
• Riboflavin intervention reduced mean blood pressure specifically in those with the TT genotype (from 144/87 to 131/80 mmHg; P < 0.05 systolic; P < 0.05 diastolic), with no response observed in the other genotype groups
• Source: Horigan et al. J Hypertens 2010

Question 15

What is primary and secondary prevention? How do omega-3 fatty acids affect primary and secondary prevention of CVD?

Answer 15

• Primary prevention is prophylactic treatment prior to any event
• Secondary prevention is prophylactic treatment after an event has already occured (e.g. after a MI)
• Omega-3 fatty acids have no benefit as primary prevention, but show reduced risk of a secondary cardiovascular event as a form of secondary prevention
  
  • Supports idea of omega-3 FAs having anti-arhythmic properties
  • Also suggests that the pathophysiological mechanisms between healthy participants and patients are different
  • Example of secondary CVD prevention: significantly lower prevalence of MIs in group given the Mediterannean diet (flatter survival curve) Source: De Lorgerii, 1994

Question 16

What is the effect of lifestyle intervention on incidence of type II diabetes?

Answer 16

• Reduces incidence, significantly more than treatment with metformin

Question 17

What are the benefits of dietary intervention as firstline treatment for those at risk of type 2 diabetes?

[EXTRA]

Answer 17

• Offer support for dietary change before as first line intervention
  
  • e.g. for people at increased risk of cardiovascular disease (NICE clinical guideline 181)
• Use disease-specific NICE guidance to identify key dietary messages – achieve and maintain a healthy weight, reduce saturated fat, sugar and salt, more fruit and vegetables
• Use NICE guidance on individual approaches to behaviour change to provide people with support to change their lifestyle (NICE Public Health Guidance 49)
• Offer people the opportunity to have their risk assessed again after they have tried to make changes

Question 18

What are the effects of obesity on health?

Answer 18

Question 19

How much weight do people need to lose to treat disease?

[EXTRA]

Answer 19

• In these trials, an average weight loss of 10% leads to:
  
  • Reduction in systolic blood pressure of:
    
    • 4 mmHg
  • And for people with high blood pressure at baseline:
    
    • 5 mmHg, equivalent to half the effect of a blood pressure tablet
  • Reduction in HbA1c of:
    
    • 2 mmol/mol
  • And for people with diabetes at baseline:
    
    • 6 mmol/mol (0.5%), equivalent to half the effect of starting metformin
• Effects on cholesterol are positive, but small.

Question 20

What are the effects of weight loss interventions on mortality in adults with obesity?

[EXTRA]

Answer 20

Question 21

What are the effects of opportunistic GP intervention on weight loss?

[EXTRA]

Answer 21

Question 22

What is the effect of total diet replacement on remission of type II diabetes?

Answer 22