Nutrition and CVD Flashcards
What spectrum of conditions and risk factors are part of cardiometabolic health?
- Metabolic syndrome and insulin resistance
- Type 2 diabetes
- Dyslipidaemia
- Hypertension
- Overweight/ obesity
- Central obesity and high levels of visceral fat
What is a lacto-ovo vegetarian?
Avoid meat and fish, but eat dairy foods and eggs
What are the components of the Nordic diet?
- Fruits, berries, vegetables and potatoes >500g/day
- Bread 4-6 slices per day
- Nuts, mostly almonds, 15g/day
- Meat <500g/week
- Poultry <300g/week
- Fish/ seafood 3-5 servings/week
- Pasta 3 servings/ week
- Cereal 1.5 servings/day
- Low-fat milk < 5dL/day
- 5g spread /bread slice
- Eggs, stay within recommended cholesterol intake
- Alcohol, habitual amount
How much can lowering BP have an affect of CVD risk?
A blood pressure drop of 55mmHg could overall reduce mortality by 14% with a 9% reduction in the risk of death from heart disease
What is the portfolio diet?
What does it include?
A plant-based diet that focuses on cholesterol-lowering foods
- 42g Nuts
- 50g Protein from soy or other legumes, e.g. beans, peas, chickpeas and lentils
- 20g viscous soluble fibre e.g. oats, barley, psyllium, eggplant, okra, apples, oranges, or berries
- 2g plant sterols e.g. enriched margarines
Kahleove at al 2019 –> Portfolio diet reduces LDL cholesterol by 17%
How does atherosclerosis affect blood vessel motility?
Restricts vascoconstriction and vasodilation due to rigidity
Blood clots may get stuck and lead to a stroke
Increase inflammation and immune response
- contribute to chronic low levels inflammation which is known to be able to lead to future cardiovascular events
What is the role of the endothelium?
Secretes substances that allow the blood vessels to constrict, dilate and form clots
e.g. Nitric oxide –> Vasodilation
Endothelial 1 –> Vasodilation
How can inflammation be measured?
C-reactive protein
Also cytokines such as IL-6, TNFa and IL-12
Women’s study in 2003 researched 28,000 women and found that those with the highest CRP at baseline had 4.4 time higher risk for cardiac events than women with the lowest CRP levels at baseline
How can diet influence inflammation
Positive energy balance can lead to obesity which is a large contributor to chronic low grade inflammation due to high proportion of adipose tissue
High red meat intake has been shown to increase CRP levels
Plant based diets has shown to be associated with lower levels of CRP when adhered to for at least two years
How can diet influence endothelial function?
Plant based diet can maintain and improve endothelial health
High consumption of saturated fat can lead to lower flow-mediated dilation (method of testing endothelial health)
How can endothelial health/ function be measured?
Flow-mediated dilation
Endo-Pat
- Non-invasive
- Reflects the vascular health of small vessels
- Takes 15 minutes
- Biosensors are placed on index fingers
How are certain dietary patterns related to BMI?
The less ‘vegetarian’ the diet is the higher the BMI
Excess fat stores –> Low grade inflammation –> Lack of vasculature in adipose tissue stores
How does WHP ratio help predict CVD risk?
Link to studies
Measures central visceral adiposity
Ratio greater than 0.5 represents increased proportions of visceral fat
Framingham heart study
- Visceral adipose tissue volume was 10% lower in individuals eating at least 3 servings of whole grains per day, compared to individuals who consumed almost no whole grains
Meat consumption
- High –> Higher BMI and waist circumference
- Low –> Lower BMI and waist circumferences
How does T2D prevalence compare in different diets?
The incidence of T2D, marked by impaired glucose metabolism, is lowest in vegans and highest in omnivores
Plant based diets improve glucose metabolism
- Reduction of insulin resistance in body tissues
- Improvement in the function of pancreatic beta cells
HbA1c level had a large reduction in DASH, Med and vegetarian diet
What is the glucose metabolism mechanism in T2D?
- Glucose enters the bloodstream
- Insulin enters the blood stream
- Cell doesn’t respond to insulin
- The cell can’t open for glucose to enter and be used for a fuel (protein cascade reaction does not occur, or is less functional meaning glucose transporters are not/ less translocated to cell membrane for glucose uptake)
With insulin resistance, glucose can’t enter cells efficiently, so it remains in high levels in the circulation
How do fat stores in muscle cells contribute to insulin resistance?
Greater insulin resistance as fat interferes with glucose uptake by muscles
The conversion of glucose into glycogen stores
Since glucose cannot enter cells, it’s left in circulation, promoting more insulin secretion in pancreatic B-cells. Persistent overworking of pancreatic B-cells can lead to dysfunction and beta cell death, further contributing to hyperglycaemia
What has been observed between glucose metabolism and diet?
Saturated fats
- Impact the beta cells that secrete insulin
- Reduce beta-cell proliferation
- Induce beta-cell death
Unsaturated fatty acids
- Protective effects
Low fat, plant based
- Improve insulin sensitivity and beta cell function in participants without diabetes
DASH, Med and vegetarian
- Improved glucose control
How does the Mediterranean Diet have cardiovascular benefits?
Studies?
7 Countries study –> Ancel Keys (1958)
- An ecological, interventional, investigation of diet and cardiovascular in 16 groups totalling nearly 13000 men in 7 countries (Greece, Italy, Japan, Finland, Yugoslavia, Netherlands and US)
1st research on the MedDiet by studying in situ the dietary patterns in italy, spain and crete and their association with cardiovascular health, with special emphasis on the effects of dietary fat and fatty acids on serum cholesterol and CVD risk
The importance of fat subtypes, and not of total fat intake, the relevance of MUFA:SFA ratio. Rich in fat (40% total calories) but with an optimal MUFA:SFA ratio appeared as an ideal model for cardiovascular health
All these fats were in accordance with the long lasting experience of use of this dietary pattern in relatively poor sectors of the world with high rates of smoking and nevertheless with a very low CHD mortality
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 Lyon Diet Heart study?
Aim
- Secondary prevention trial aimed at reducing the risk of cardiovascular deaths and recurrent MI by diet modification in 605, survivors of a previous MI and recruited between 1988 and 1992
Methods - patients were randomised to
MedDiet
- High consumption of fruit, vegetables, bread and fish
- Low consumption of red meat
- Replace butter and cream by a special margarine
Control
- Diet similar to the low fat step 1 diet of the American Heart association
Results
- A dramatic reduction in major coronary events and death, that was maintained over a 4 year follow up period. Interim analysis at 27 months of follow up, 73% reduction in coronary events and 70% reduction in total mortality
What is the PREDIMED study?
A study in 2013 that looked at the primary prevention of cardiovascular disease with a Mediterranean Diet.
Randomised trial of the diet pattern for the primary prevention of cardiovascular events
Dietitian led
Participants all at risk of CVD e.g. pre-diabetes or metabolic syndrome
7447 randomised participants
- MedDiet supplemented with extra virgin olive oil (1L/ week / family) –> 2543 participants
- MedDiet supplemented with mixed nuts (30g/ day), 7 almonds, 4 walnuts and 7 hazelnuts (raw) –> 2454 participants
- American Heart Association low fat diet, no energy restriction (control) –> 2450 participants
Both MedDiet interventions showed a decrease in mortality and incidence of CVD.
A dietary intervention with the MedDiet carried out by a dietitian in primary care setting can reduce by 30% the risk of suffering from cardiovascular disease and associated mortality
What are the potential mechanisms of how the MedDiet could protect against CVD?
- High fibre content
- Low caloric density
- High nutrient density
- Lower saturated fay
- Beneficial fatty acids composition (higher in unsaturated fats)
- Anti-inflammatory compounds
A better control of risk factors to improve
- Lipid profile
- Inflammation
- Oxidation
- BP
- Glucose metabolism
- Without affecting body weight
What are the beneficial components of the MedDiet?
- Minerals
- Polyphenols
- Fibre
- Vitamins
- Minerals
- MUFAs
- PUFAs
Individual food components
- Olive oil
- Nuts
- Legumes
- Fruit
- Vegetables
- Whole grains
How does nut consumption influence CVD?
67g nuts associated with
- 5% decrease in total cholesterol
- 7% decrease in LDL
- 3% decrease in triglycerides
- 0.09% increase in HDL
Nut consumption benefits can be shown in blood lipid profile
High in magnesium, fibre low GI, ALA a3, antioxidants, MUFA, arginine
Shown improvement in
- Endothelial function
- Inflammation
- Insulin resistance
Which overall contributes to reduced cardiovascular mortality
Nuts
Satiety –> Decreased energy intake from other foods –> decreased adiposity
- Rich in fibre which contributes to satiety
Energy metabolism –> BEE –> Postprandial thermogenesis –> Fat oxidation –> Increased energy expenditure –> decreased adiposity
- More energy required to digest nuts, increase energy expenditure
Incomplete intestinal absorption –> Foecal energy loss (fat) –> Decreased adiposity
10-20% of energy from nut is lost in faeces, which is a reason why weight gain isn’t seen (often).
Food intake study in Spain showed that those with the lowest BMI had the highest intake of nuts. Also shown that those with the lowest BMI had the highest adherence to the MedDiet
Discuss nut consumption and insulin resistance
A 90 day study with the intervention group that consumed a healthy diet + 30g nuts/day and a control with just a healthy diet.
A stool sample was taken.
Results showed that the intervention group there was a decrease in the hormone insulin resistance markers in comparison to the control group
- higher fat content in stool
MUFAs shown to improve beta cell efficiency which could improve insulin sensitivity
