Role of diet in CVD Flashcards
What mechanisms can diet influence that result in high risk of CVD?
- High blood lipid levels
- Hyper tension
- Insulin resistance
- Inflammatory response
- Oxidative stress
- Thrombotic tendence
- Endothelial function
- Homocysteine level
- Obesity/ physical activity
—>
Injury to coronary arteries
- Blood pressure, lipid oxidation and inflammation
Fibrous plaque formation
- Atherogenic lipid profile, elevated homocysteine clotting factors and insulin resistance
Thrombosis and heart attack
- Platelet aggregation, clotting factors and arryhthmia
What are some drivers of poor diet quality?
- Lack of knowledge
- Lack of ability
- Price
- Time scarcity
- Social and cultural norms
- Marketing and branding
- Taste and flavour
What is the primary prevention of CVD?
Diet and lifestyle
- Poor BP
- Lipid control
- Glucose control
- Thrombotic tendency
- Inflammation
Medication
- Plaque formation
What are some reasons for a decrease in CVD mortality since 1970?
- Better treatments and healthcare
- Medications
- More research and knowledge
- Prevention –> groups and programmes
- Wide spread information, advertising
- Smoking ban
- Saturated fat guidelines
- Salt intake recommendations
- Fruit and vegetables 5 a day recommendations
How has the prevalence of CVD and some common affects e.g. stroke, changed over the years.
In UK
ncrease in percentage of CVD cases in both men a women, increased over 1990.
- Increase in obesity
- Increase access to low quality and highly
processed foods
- Increase of physical inactivity
- Increase of pollution
Stroke and heart attack prevalence remained similar
- medication to help prevent development
CVD hospitalisation episodes slightly increased in both men and women, much higher in med than women.
Nationally
- Increased prevalence in Russia and Kazakhstan
- Decrease in Italy and Germany
(Death rates)
What are the dietary recommendations to prevent CVD and help with heart health
- <6g salt
- <5% of food energy from free sugar
- <11% of food energy from saturated fat
- 30g fibre
- > 50% of food energy from CHO
- <35% of food energy from fat
- At least 5 portions of fruit and veg per day
- At least 2 portions of fish per week, one of which should be oily
SACN (2017) - 30g unsalted nuts
- Alcohol limited to 2 glasses per day for men and 1 glass per day for women
- Sugar-sweetened soft drinks and alcoholic beverages consumption must be discourage
- 30-45g fibre per day, preferably from wholegrain products
European heart network (2016)
What is the Seven Countries Study?
First epidemiological study from CVD
Occurred in 1980 –> Ancel Keys - University of Michigan in 1940s
Included USA, Netherlands, Finland, Greece, Italy, Japan and Yugoslavia
Risk factors for CVD identification in different countries (Population level)
High saturated fat intake increases CVD risk, as shown in USA and Finland who had much higher results than other countries such as Japan and Corfu.
Found the links between diets high in saturated fat also are high in cholesterol which is a risk factor for CVD.
The first study that found saturated fat in diet is linked to CVD in different populations
What is the Framingham heart study?
Ongoing study which started in 1948, currently studying the 3rd generation of the study.
- studying epigenetics and comparing results with previous generations
Single population
In 1940 in the US there was an increase in CVD mortality, so the aim of the study was to identify the risk factors and links to genes.
1948
- Research men and women 30-62 years, assessed every 2 years
1971
- Offspring cohort
- Spouses and children recruited
2002
- Third generation cohort
- Grandchildren recruited
What is the Interheart study?
Case control study in 2004, that investigated the myocardial infarction and risk factors
In 52 countries
Identified 9 risk factors –> accounted for 90% for men, 04% for women
8 out of 9 were related to diet –> Alcohol, dietary patterns, history of hypertension and diabetes, waist hip ratio, LDL:HDL ratio, psychosocial
Globally 80% of first occurrence of MI was predicted by combination of
- smoking
- dyslipidaemia
- hypertension
- diabetes
- obesity
What is the relationship between saturated fatty acids and serum cholesterol?
After Keys study, there was lots of research done looking at the link between SFA and serum cholesterol.
It was found that dietary intakes of saturated fat were associated with increases in total blood cholesterol along a linear trend
It has been found that the quality of dietary fat is important and has an impact of total and LDL cholesterol (Schwab et al 2014)
Links between LDL and atherosclerosis link
Genes increase risk, which is highly influenced with poor diet.
Partial replacement of of SFA with MUFA or PUFAL decreased serum LDL without effecting HDL (Schwab et al 2014)
Small change in SFA in cohort may lead to even smaller mean change in LDL/ total cholesterol due to individual differences
Important to understand what has replaced SFA in diet
Studies show a relationship between cholesterol and CVD
What have studies found in replacing SFA in diet?
- Replacing SFA with carbohydrates with low -GI is associated with a lower risk of MI, whereas replacing with high-GI is associated with higher MI risk (Jakobsen et al 2010)
- Replacing SFA with PUFA decreases serum LDL without affecting HDL (Schwab et al 2014)
What is the Health Professional Follow-up study?
FInding?
Data from Nurses Health study (1984-2012) and Male Health professional study (1986-2010) supports a link between SFA and CHD.
Conclusion
- Higher intakes of major SFAs are associated with increased risk of CHD. Owing to similar association and high correlations among individual SFAs, dietary recommendation for prevent of CHD should continue to focus on replacing total saturated fat with more healthy sources of energy
Different SFAs have differing risk implications for SFA which helps explain some inconsistency in results.
Substitution of SFA with trans fat and CHO from refined starches/ added sugar increases risk of CHD
Substitution with MUFAs, PUFAs and CHO from wholegrains reduces the risk.
What os the SACN report of SFA?
(2019)
- Average contribution of SFA to total dietary energy should be reduced to no more than 10%. This applies to adults and children aged 5 and over
- Saturated fats to be substituted with unsaturated fats. More evidence supporting with PUFA than MUFA –> shown decrease in cardiovascular diseases
- Substitution of SFA with unsaturated fats shown to decrease total cholesterol and LDL cholesterol
What are the guidelines surrounding cholestero?
Currently guidelines = 5.2mmol/L however a 3.8mmol/L is now suggested as being beneficial and desirable.
This would probably require an intake SFA of 5% TEI
Government suggest that total cholesterol levels should be 5mmol/L or less for healthy adults and 4mmol/L or less for those at high risl
Has omega-3 fatty acid supplementation found to help with CVD risk?
Aung et al (2018)
- No significant association with fatal or non-fatal CHD or any major vascular events
Hu et al (2019)
- Marine omega-3 supplementation lowers risk for MI, CHD death, total CHD, CVD death and total CVD.
Some contradicting studies
