Lecture 23: Primary Preventions - smoking, alcohol and food

Question 1

what are the lifestyle factors recommended to reduce CVD?

Answer 1

• diet
• weight management
• physical activity
• smoking cessation

Question 2

how does smoking relate to CVD?

Answer 2

should already know this from the cancer module

• but smoking cigarettes is an important risk factor for CVD as well as cancer.

Question 3

what is a ‘heart healthy’ diet?

Answer 3

the Heart Foundation has a guideline for people to refer to.

suggests to:

• eat mostly fruits and vegetables
• eat some breads, cereals, grains and starchy vegetables (wholegrain and high-fibre)
• eat some fish, meat, chicken, legumes, eggs
• some milk, yogurt, cheese
• less oils nuts
• cut back on junk, takeaways, sugary, salty and fatty food and drink
• the Harvard healthy plate has similar guidelines

Question 4

what does this show?

Answer 4

a study that shows that dietary factors are important!
- number of deaths and age-standardised mortality rate attributable to individual dietary risks at the global and SDI level in 2017

• dietary risk factors are just as important as smoking risk factors for non-communicable diseases
• the top of the graph shows that diets high in sodium but low in whole grains, fruits, nuts, seeds and vegetables contribute most to mortality and CVD events
• interesting to note that low-middle income countries have less regulation of transfats in their food and as a result experience more diet-related mortality compared to higher income countries who do regulate trans fats.

Question 5

what are the fatty acids in our diet?

Answer 5

• saturated fatty acid
• trans-fatty acid
• monosaturated fatty acid
• polyunsaturated fatty acid

Question 6

what are saturated fatty acids? (SAFA)

Answer 6

animal fats:
- butter, full fat milk and dairy foods, fat on meat, skin on chicken. Also, palm oil and coconot oil

Question 7

what are trans-fatty acids? (TFA)

Answer 7

• partially hydrogenated vegetable oils; processed foods like pastries, cakes, biscuits

Question 8

what are monounsaturated fatty acids? (MUFA)

Answer 8

• olive oil, avocado, peanute, canola, ricebran oil, nuts
• important component of mediterranean diet

Question 9

what are polyunsaturated fatty acids? (PUFA)

Answer 9

• sunflower oil, safflower oil, soybean oil, polyunsaturated margarines
• fish oils (omega-3 fatty acids)

Question 10

what does this show?

Answer 10

• the 7 countries study
• close examination of dietary patterns in these countries with different rates of coronary artery disease mortaliy
• looked at the proportion of calorie intake from each type of fat

Kyushu (japan) had a total fat intake of 9% (3% each fat)

while countries like Finland had 39% total fat (22% saturated, 14% monounsaturated, 3% polyunsaturated)

Question 11

what does this show?

Answer 11

linear relationship between the proportion of saturated fat and serum cholesterol

Question 12

what does this show?

Answer 12

linear relationship between serum cholesterol and CHD mortality
- first suggestion that saturated fat was risk of CHD

Question 13

what were the findings of the cochrane study?

Answer 13

there were 15 randomised control trials with 15,000 participants

found that cutting down on saturated fat had a 17% reduction in the risk of combined CV events, but had a limited impact on the risk of dying

• health benefits came from replacing saturated fat with polyunsaturated fat or starchy food
• no difference in men and women

Question 14

what does this show?

Answer 14

this is a dose-response analysis

• found evidence of a cutpoint at 9% energy from saturated fat
• if you eat below 9% it a benefit for CV events and mortality
• most dietary guidelines recommend less than 10% energy from saturated fats

Question 15

what is important to consider when replacing fats in your diet?

Answer 15

you need to substitue it with something healthy!!

• Reducing fat became a marketing ploy
• Unhealthy foods said they were low fat (e.g. marshmallows)
• Replacing saturated fat from healthy source of food with unhealthy food is not a good idea. Cutting down on things, you need to be careful with what you replace it with

Question 16

what was the nurses health study and health professionals follow-up study?

Answer 16

• was a cohort study that had a 24-30 year follow up
• established in 1976-121,700 females nurses aged 3-55 years

Question 17

what were the findings of the nurses health study and health professionals study?

Answer 17

if you replace saturated fats with trans fats or carbohydrates from refined starches or added sugars, there was an increased risk of coronary heart disease, but replacing SFAs with MUFAs, PUFAs or carbohydrates from whole grains had a decreased risk

• so don’t elimate fat out of diet completely

Question 18

what is the eating and activity guidelines for NZ adults?

Answer 18

choose and/or prepare foods with unsaturated dats instead of saturated dats

• recomended intake of saturated fats and trans fats together is no more than 10% of total energy

Question 19

what is the WHO guideline for sugar?

Answer 19

• sugars should be less than 10% of total energy intake per day
• a reduction to below 5% of total energy intake per day would have additional benefits
• 5% total energy = 25g = 6tsp

Question 20

what does this show?

Answer 20

once you have above 10% sugar intake, there is an associated increased risk of CVD mortality

Question 21

what is the lifestyle recommendation to lower blood pressure?

Answer 21

body weight: aim for a normal body mass index (18.5-24.9 kg/m2)

reduce sodium intake

DASH-style dietary pattern (dietary approaches to stop hypertension): high in fruit and veges, high in dietary fibre and low-fat dairy products, low saturated fats

moderate alochol intake: no more than 1 standard drink for women or 2 standard drinks for men per day.

Question 22

how does sodium/salt link to CVD?

Answer 22

strong associated of sodium to blood pressure and CVD

• range on consistent evidence linking sodium intake to elevated blood pressure
• animal studies
• epidemiological studies
• migration studies
• population intervention studies
• treatment trials

Question 23

what does this show?

Answer 23

low systolic blood pressure is associated with a decreased sodium
- average of -5.4mmHg

(hypertension people)

Question 24

what does this show?

Answer 24

people with a normal BP (non-hypertension) had a lower SBP with decreased sodium (-2.4mmHg) - smaller reduction than hypertension people

the overall effect:
- lower SBP associated with decreased sodium -4.2mmHg

Question 25

what is the link between sodium intake and CVD events?

Answer 25

reduction in risk of CVD events with decreased sodium RR 0.80 (95%CI- 0.64,0.99) = 0.04

Question 26

what are the WHO recommendations for sodium?

Answer 26

- adults should have \<2000 mg sodium per day (5g salt or around 1 tsp) - in 2010 global mean sodium intake was estimated to be 3.95g/day (children should have less than this)

Question 27

how could we limit salt intake?

Answer 27

- consumer awareness and education - improvements in food labelling - reformulation of precesses according to specific targets (with a sinking lid) - salt substitutes

Question 28

what are some public health interventions that could improve nutrition?

Answer 28

- improvements in food labelling - reformation of processed food to contain: more fibre, less salt and sugar, less SFA, more PUFA - taxes and subsidies - reduce marketing of 'junk food' especially to children - make only healthy food available in schools, hospitals and other government institutions - education and guidelines - availablility of fresh produce, minimise food deserts

Question 29

what is interesting about alcohol and CVD?

Answer 29

- the J shaped curve! - this graph shows that more wine consumption = less mortality by IHD per 1000 men - "french paradox" - low mortality by IHD despite most wine consumption - is it something to do with confounding?

Question 30

what does this show?

Answer 30

20g/day or less alcohol intake shows a decreased relative risk of coronary heart disease - after 20g/day the risk starts to increase (j shaped curve)

Question 31

what does this show?

Answer 31

- gender effect: women have higher risk of coronary heart disease due to alcohol consumption.

Question 32

do we believe that alcohol can be a protective factor to some degree?

Answer 32

biological plausibility: - lipid effects (increases HDL-cholesterol) - platelet effects (aspirin-like), fibrinolysis - glucose metabolism (decreased diabetes) consistency amonst studies: - large, well-conducted cohort studies BUT: - no RCTs - patterns of alcohol use associated with other health related behaviours - confounding?

Question 33

public intervention to reduce harmful consumption of alcohol?

Answer 33

look at injury module? hopefully should know this already.