Diet and cardiovascular disease Flashcards
What are the cardiovascular diseases?
coronary heart disease
stroke
peripheral vascular disease
(main cause of this being atherosclerosis)
Rheumatic heart disease-Damage to the heart muscle and heart valves from
rheumatic fever, caused by streptococcal bacteria
congenital heart disease - malformations of heart structure existing at birth
deep vein thrombosis and pulmonary embolism
What is coronary heart disease?
- stable and unstable angina
- acute myocardial infarction (“heart attack”)
- sudden death, with or w/o history of chest pain
and/or previous infarction
What is stroke?
sudden localised loss of brain function due to ischemia
or haemorrhage, and lasting longer than 24h. In the UK,
85% of the cases are due to ischemia essentially due to
thrombosis, the rest to emboli. Hemorrhagic strokes are
the consequence of the rupture of the arterial wall due to
aneurysm or wall disease
What is peripheral vascular disease?
Disease of the aorta, and iliac and leg arteries. Often
coexist with CVD
What is atherogenesis?
process that leads to the thickening of the arterial wall. Which gradually reduces the lumen- then blood to concerned tissue and therefore reducing oxygen supply.
When lumen of artery is sufficiently reduced to limit blood flow and oxygen supply - then develop a different type of disease depending on the artery concerned.
What disease does one develop if coronary arteries are blocked?
ischaemic heart disease
What disease does one develop if the carotid or brain arteries are blocked?
stroke
What disease does one develop if aorta or leg arteries are blocked?
peripheral vascular disease
Describe the development of the atherosclerotic plaques?
development of fatty streaks (deposit of lipids within the arterial wall and the presence if inflammatory cells- macrophages, foam cells and T lymphocytes)
fatty streaks can evolve into lipid rich plaque (well defined lipid deposit- oxidised cholesterol).
Lipid core has a fibrous cap- composed of a monolayer of endothelial cells with some smooth muscle cells)
If fibrous cap is not too inflamed and thick and lumen of artery not too reduced- then fine.
Possibly due to a strong inflammatory component - fibrous cap can be weakened and prone to rupture. When this happens you get blood entering and contact with lipid core, oxidised lipid are very pro thrombotic - formation of thrombus.
process starts with endothelial dysfunction- endothelial cells when become dysfunctional will produce less nitric oxide.
More LDL can now penetrate arterial wall (low density lipoproteins) - which can linger longer within arterial wall and where they can be more prone to and susceptible to oxidation.
Triggers recruitment of monocytes from circulation and they will enter the arterial wall and transform themselves into macrophages. Macrophages will scavenge the modified and oxidised LDL and evolve into foam cells (much bigger, different phenotype and pro-inflammatory).
Foam cells secrete diff cytokines, chemotoxic agents (to recruit more monocytes). Interaction with T cells of TH1 type to induce changes in smooth muscle cells and fuel the chronic inflammation. Formation of fibrous cap.
Foam cells can become necrotic and die by apoptosis and this leaves lipid deposit where they die- inside arterial wall.
What triggers endothelial cell dysfunction?
hyperlipidemia
infection
high blood pressure
various chemical components
What are the main risk factors for CVD?
HYPERTENSION- can be triggered by obesity (risk factor itself)
INSULIN RESISTANCE- triggered by obesity
DIABETES
genetically prone - mutation of LDL receptor or mutation of lipid protein- leading to hyperlipidaemia.
Foetal and infant growth-
High alcohol consumption - raises blood pressure
Smoking - affects vascular endothelial function
Low physical activity
What are the prevention strategies for tackling CVD?
tackling unhealthy lifestyles
optimising risk factors
What diet is pro-atherogenic?
Cholesterol
Saturated FA
Trans FA
Sodium
Alcohol
What diet is anti-atherogenic?
PUFA
CHO-rich diet
NSP
MUFA
Antioxidant?
Phytochemicals
What percentage of reduction of plasma cholesterol translates to 2-3% reduction of CHD?
1%
What is hypercholesterolemia due to?
poor life style or genetic
What is HDL cholesterol associated with?
lower risk of CHD (coronary heart disease) but only when LDL cholesterol is high.
What kind of fat is cholesterol found in?
saturated
problem with eating too much saturated fat?
impair lipid metabolism
Where do you find saturated fatty acids?
palm oil, butter
Which saturated fatty acids are especiallt bad?
myristic acid - coconut oil
palmitic acid - palm oil
Effects of saturated FA on LDL receptors?
inhibition and suppression
aggregatory effects
Where do you find trans fatty acids?
in processed food and naturally occurring in dairy products
Effects of trans fatty acids?
Raise LDL cholesterol and plasma triglycerides
and lower HDL cholesterol
How percentage of energy replacing trans fats with unsaturated would reduce CHD risk by 12%?
1%
How does sodium influence thrombosis?
effect on blood pressure
How many units would raise blood pressure?
30 units weekly
Where are the n-6 polyunsaturated fatty acids found?
sunflower oil
Effect of n-6 polyunsaturated fatty acid?
high intake of n-6 PUFA (substitution of saturated FA) lower
LDL cholesterol, but also HDL cholesterol (only for 13%
energy or more).
Where do you find Monounsaturated FA: mainly oleic acid?
olive oil
Effect of Substitution of saturated FA by oleic acid?
reduces both total
and LDL cholesterol in the plasma.
Where do you find n-3 PUFA?
one from plant origin - alpha linolenic acid ( essential FA found in linseed, canola and rapeseed) - not anti-atherogenic
one from marine-(oily fish) Powerful reducing effects on TAG plasma levels but minimal
effects on LDL and HDL levels.
They have also potent anti-inflammatory and anti-thrombotic
properties.
Effects due to long chain one (EPA and DHA) but not α18:3
What is relationship between carbohydrate intake and fat intake?
When carbohydrate intake increases, fat intake tends to decrease, and vice versa. This is because both macronutrients are primary energy sources, and the body will typically prioritize one over the other depending on availability.
What percentage of daily intake should be carbs?
50%
What percentage of intake should be free sugars?
no more than 5% daily energy intake
What is increase of dietary non starch polysaccharide (fibre) associated with?
correlated with a decrease risk of CVD
Help reducing
cholesterol level, but no effect on VLDL and TAG levels.
Perhaps beneficial effects on insulin secretion
Beneficial effects on gut health
What are antioxidants for?
Antioxidants are essential components of the cellular
defence against activated oxygen species
Give examples of antioxidants?
They include Se, Zn, Mn, vit C and E, as well as carotenoids
(βcarotene, luthein and lycopene) and flavonoids. High intake
of vit C, E and fruits and vegetables are associated with lower
risk of CVD
How has tea been linked to decreased risk of CVD?
Some evidence for green tea, due to catechin content.
evidence. No effect of black tea.
How has garlic been linked to decreased risk of CVD?
Bioactive ingredient is allicin.
Reduce platelets aggregation, increase fibrinolysis, decrease
plasma fibrinogen. Potential effect on blood pressure,
cholesterol and CRP
