Dyslipidemia & CVD 2 Flashcards
Lifestyle modification approach for tx of dyslipidemia
- diet
- weight management : healthy and sustainable
- physical activity
Benefits of weight loss of 2-7kg in terms of blood lipid profile?
- decrease LDL-C by 0.1 mmol/L
- decrease HDL-C by 0.03 mmol/L during loss and then increase by 0.04 mmol/L during maintenance
- decrease TG by O.07 mmol/L
Benefits of physical activity (1200-2200kcal/week) in terms of blood lipids?
- decrease TG by 4-37%
- increase HDL-C by 2-8%
- decrease LDL-C by 0.7%
=> accentuated with weight loss
Effect of resistance exercise
Little effect
Which PA has the greatest benefits (kcal spent)
Volume/intensity of exercise
Which PA has little effect on lipid profile
Resistance exercise
Limitations of predictive equations
- different SFA have different effects
- predicts total cholesterol only
- assumes MUFA and carbohydrates are neutral
- effects on total cholesterol may not be linear
Studies in 60s, 70s show:
Increased cholesterol in diet increases serum cholesterol levels
(don’t distinct LDL versus HDL)
The 7 Countries Study =
- by who
- result
- Ancel Keys
- result:
- east Finland has the highest coronary deaths (on regressive line)
- Ushibuka has the lowest coronary death (on regressive line)
- Crete (mediterranean diet) = outlier not on regressive line,
What +ve relationship was found by Keys?
+ve relationship between serum cholesterol and mortality due to heart disease
What is dietary cholesterol and what is its impact on blood cholesterol levels
- found only in animal foods
- less effect on raising blood cholesterol than saturated fats but may be significant in some individuals
- very heterogenous responses to cholesterol
How is the response to dietary cholesterol heterogenous ?
There are compensators (2/3) and non-compensators (1/3)
T/F
Dietary cholesterol has a higher effect on raising blood cholesterol than saturated fats
False
But could be significant in non-compensators
Average amount of cholesterol consumed
200-300mg/day
What happens when non-compensators ingest cholesterol?
Increases synthesis and activity of LDL receptors
Independent mechanisms of dietary cholesterol
- decreased synthesis and activity of hepatic LDLr
- increased cholesterol in chylo and chill remnants –> more atherogenic and increased cholesterol delivery to liver
- increased cholesterol in VLDL and VLDL remnants –> more atherogenic
- interferes with ability of HDL to clear cholesterol
T/F
Cholesterol content is directly proportional to fat content
False
ex: high cholesterol in kidney, pancreas, liver but low fat
ex2: high fat in beef, lamb, pork, veal but low cholesterol
Highest source of cholesterol
Brains > pancreas > kidney > liver
Highest cholesterol content in fish & shellfish is in _
shrimp
Total kcal from fat goal = _
25-35% of calories
Also helps to reduce T calories and saturated fat intakes
Current intake in North America
34-37% of T kcal
Which type of diet may decrease HDL-C which is not beneficial?
Very low-fat diet
Is quantity or type of fat important?
Type of fat (or quality)
How do saturated fatty acids reduce activity of LDL receptors?
- decrease transcription of LDL receptor gene
- alter PL composition of cell membranes to decrease binding
- alter LDL itself and delays binding to receptors
What was the first recommendation by NCEP and USDA for SFA?
Goal was less than 10% of T kcal from SFA
Major sources of SFA (US)
- highly processed foods
- processed meats
- baked goods (cakes, cookies, donuts)
- pizza
- cheese
- ice cream
Primary contributor to total SFA intake in Canada
“All other foods” category which is not part of the CFG
New recommendations by Heart and Stroke Canada, CFG in terms of saturated fats are _
no limit on saturated fats but focus on a healthy balanced diet
Substitution of SFA to improve lipid profile and reduce CVD risk
- replacing SFA with MUFAs and PUFAs
T/F
Replacing SFA with carbohydrates is beneficial in CVD risk
F
depends on source of carb
How dietary SFA affects lipid profile
increases LDL-C
increases HDL-C (depends on source)
Medium chain SFA
Caprylic (8)
Caproic (10)
Intermediate chain SFA
Lauric (12)
Long chain SFA
Myristic (14)
Palmitic (16)
Stearic (18)
Which SFA are directly absorbed into portal vein and don’t go through CM
Medium chain SFA (<10)
SFA that increase LDL-C
- Lauric
- Myristic
- Palmitic (in presence of high cholesterol)
Stearic effect
neutral effect
Effects of medium chain SFA (<10) on serum cholesterol
No effect
Effect of SFAs on VLDL
None
Effects of SFAs from dairy products
decrease CVD risk (compared to SFA from meat)
Effects of SFAs from cheese
less increase LDL compared to butter
Highest SFA in :
- coconut oil
- butter
- palm oil
- coconut oil = high lauric
- Butter = high palmitic
- palm oil = very high palmitic
Coconut Oil vs butter
- Co has higher %SFA than butter
- Co has high lauric acid
- B has high palmitic acid
- Co better than butter but worse than other vegetable oils
Trans FA impact on lipid profile
- increase LDL-C
- reduce LDL size
- reduce HDL-C
- increase inflammatory markers (+endothelial damage)
Consumption of trans FA
3% T kcal (decreasing)
Sources of trans FA
- heard margarine
- partially hydrogenated oils
- dairy (small amounts, better effect)
Trans fat consumption should be _
avoided
Trans fat occurs as a result of _
partial hydrogenation
Unsaturated fatty acids in the diet
- Omega 9 (oleic acid)
- Omega 6 (linoleic acid)
- Omega 3 (linolenic acid, EPA, DHA)
Omega-6 effect on lipid profile
- increases LDL clearance
- may decrease HDL formation and/or Apo-A1
Risk of high PUFAs
inflammation, increased oxidative damage to LDL
Omega-6 sources
corn, sunflower, safflower, soybean oils, walnuts, sunflower seeds
Goal of omega 6 in diet
5-10% of calories
Main Mono-unsaturated FA
Oleic acid
Source of MUFAs
olive, canola oil, peanuts, meat, poultry
Effects of MUFAs on lipid profile
- does not lower HDL-C
Goal of MUFA in diet
<20% of T kcal (assuming a lower saturated fat diet)
Advantages of MUFAs
- don’t decrease HDL like PUFA and carbs
- less susceptible to oxidation than PUFA
- don’t increase TG as carbs often do
- don’t increase cancer risk of high PUFA could
MUFAs are characteristic of __ diet
Mediterranean
Dietary sources of linoleic acid
safflower oil
soybean oil
corn oil
sunflower oil
Dietary sources of oleic acid
olive oil canola oil (rapeseed) peanut oil avocados nuts
Types of Omega-3 PUFAs
- EPA: eicosapentanoic acid
- DHA: docosahexanoic acid
- ALA: alpha linolenic acid
DHA & EPA sources
fish
ALA sources
canola, linseed, soybean oil
Omega-3 effects on lipid profile
- decrease TG in hyperlipidemic and hyperTG patients
- don’t lower LDL-C
T/F
CCS recommendations promote use of omega-3 PUFA supplements to reduce CVD events
False
they emphasise on good sources such as fish, omega 3 fortified eggs
Omega 3s __ risk of mortality in those with CVD
reduce
Omega 3s interfere with :
platelet aggregation and prevent coronary thrombosis
delay proliferation of fibroblasts
Omega 3s reduce/ increase plaque formation and growth
Reduce (because they reduce adhesion of molecules)
T/F
Omega 3s reduce the number of VLDL particles being secreted by the liver
False
Omega 3s decrease the TG content of the VLDL particles
Goal of fiber in diet?
20-30g/day
50% soluble fiber
Soluble fiber effect on lipid profile
- decrease total-C
- decrease LDL-C
(depends on initial level of hyperchlesterolemia)
Soluble fiber sources
oats legumes pectins psyllium gums
Carbohydrate effect on lipid profile
- increased VLDL-TG production
- decrease HDL-C
Disadvantage of high CHO diet (mostly simple CHO)
- decreased HDL and increased TG
- Hyper TG in some populations
- increase BG and hyperinsulinemia
Alcohol effect on lipid profile
- increased HDL-C
Is it okay to consume alcohol? How much?
OK if consumed in moderation
1-2 drinks/day
Which alcohol may inhibit cell-mediated oxidation of lipoproteins? Why?
Red wine
Due to resveratrol (polyphenol)
What is the French paradox?
That red wine polyphenols decrease risk of CHD (eventhough French have a high saturated fat diet)
Why should alcohol be avoided COMPLETELY if have familial hypertriglyceridemia?
Because alcohol inhibits acylCoA oxidation in the liver (–> TG formation)
Soy protein effects on lipid profile
- reduces Total-C
- reduces LDL-C
- reduces TG
- no effect on HDL-C
Food sources of soy protein
tofu
soy beverage
soy protein isolates
tempeh
US Health claim that __ g of soy protein, as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease
25g
Which compounds present in soy protein are beneficial
isoflavones
phytoestrogens
3 antioxidants are
vitamin C
vitamin E
beta-carotene
Antioxidants effect on lipid profile
May inhibit LDL oxidation (decreases atherosclerosis risk-
Are antioxidant supplements recommended
No
Hyperhomocysteinemia increases/decreases incidence of CVD ? At which amount?
INCREASES
> 14umol/L –> increased risk of heart disease
What is hyperhomocysteinemia caused by?
deficient folate and B6 causes high homocysteine
in which patients does hyperhomocysteinemia appear?
in up to 40% of patients with CVD
Does B12 deficiency elevated homocysteine?
No
Which deficiencies elevated homocysteine?
Folate
B6
What are recommendations to avoid hyperhomocysteinemia
- increase food sources of folate
- supplement (500yg/d ONLY if high levels or family history of CVD
Before supplementing folate which deficiency should you be careful about?
B12 deficiency could be masked
T/F
Low levels of B12 are associated with increased risk of CHD
False
Food sources of folate
fortified cereals vegetable citrus fruits/juices legumes organ meats
What are phytosterols/stanols?
What do they compete with?
- Are equivalent to plant cholesterol
- - Compete with cholesterol absorption : increase decal excretion
Diet enriched with 2-2.5g sterols/stanols reduced __ by 6-14% ?
LDL-C
Main source of stanols/sterols
Fortified margarine
Nuts are rich in which FA ?
rich in: mono- and polyunsaturated FA
low in: SFA
Nuts are rich in what other nutrients ?
plant protein soluble fibers folic acid antioxidants arginine (= Nitric oxide precursor)
High intake (30-60g/d) __ risk of CHD.
Reduces
Moderate intake of nuts reduces which lipid?
Reduces LDL-C and improves endothelial function
T/F
Eating nuts has a notable effect on body weight
False
NCEP =
National cholesterol education program (created the dietary approach for dyslipidemia)
Dietary approach of dyslipidemia targets:
1st target = LDL-C
other targets = metabolic syndrome factors (TG, HDL, waist circ)
What model does the dietary approach of dyslipidemia follow?
TLD model = therapeutic lifestyle changes
Therapeutic lifestyle changes decrease/ increase:
- decrease saturated fats and dietary cholesterol
- increase physical activity
- weight management to reduce coronary risk
- Step 1 to decrease saturated fats and cholesterol
- Step 2 and 3
Step 1: < 10%SFA and < 300mg cholesterol
Step 2 and 3: <7% SFA and <200mg cholesterol
Which diets (2) can be used for prevention or treatment of dyslipidemia ?
- The Mediterranean diet
- The Portfolio diet
The Mediterranean diet is high in
- oleic acid (olive oil)
- fruits, vegetables, legumes
- fish
The Mediterranean diet is low in
- red meat
The Mediterranean diet is moderate in
- dairy (cheese and yogurt)
- wine consumption
Results of Mediterranean diet
- decrease in CV events
- decrease LDL-C, app-B, TG
- increase HDL-C
- additive effect to statins
- decrease inflammatory markers
Mediterranean diet has a decrease in mortality of _ %
25%
= very high
What is the Portfolio diet?
- vegetarian diet
- low in saturated fat
- high in phytosterols, soy proteins, soluble fibres, almonds
Results of Portfolio diet:
- decrease in 29% LDL-C
- decrease CRP
What is the problem with the portfolio diet?
Has a low adherence (40-45%)
Was done in a very controlled environment
A low-fat diet with satins decreases LDL-C by _%. Is it more or less than the portfolio diet.
31%
More
CCS Guidelines 2016 in terms of dietary recommendations
- healthy eating and activity and Mediterranean dietary pattern to lower CVD risk
- omega-3 PUFA supplements should not be used to reduce CVD events
- avoid intake of trans fats
- decrease intake of saturated fats for CVD risk reduction (substitute SFA with PUFAs)
- moderate energy intake to maintain/achieve a healthy body weight
- adopt a healthy dietary patterns
Healthy dietary patterns recommended by CCS Guidelines
- Mediterranean
- Portfolio
- DASH
- high in nuts (30g+/d)
- high in legumes (4servings+/d)
- high in olive oil (60mL+/d)
- rich in fruits and veg (5servings+/d)
- high in total fiber 30g+/d) and whole grains (3servings+/d)
- low-glycemic load or low-glycemic index
- vegetarian
Dietary factors that increase HDL-C
- saturated fats
- dietary chol
- alcohol (less han 2drinks/d)
Dietary factors that decrease HDL-C
- simple sugars/high carb diet
- polyunsaturated fat, high
- obesity
Other factors that increase HDL-C
- long-term aerobic exercise program
- estrogens
- female sex
Other factors that decrease HDL-C
- androgens
- male sex
- anabolic steroids
- some antihypertensive drugs
- diabetes mellitus
- cigarette smoking
What do Statins inhibit
HMG-CoA reductase
Statins examples:
- atorvastatin (Lipidor)
- lovastatin (Mevacor)
- simvastatin (Zocor)
- rosuvastatin (Crestor)
- pravastatin (Pravachol)
Mechanism of statins
Block cholesterol synthesis
Increases LDL receptor mediated removal
Predicted effect of statins
- decrease LDL-C
- decrease TG
- increase HDL-C
4 classes of drugs to treat hyperlipidemia
- HMGCoA reductase inhibitors (Statins)
- Cholesterol absorption inhibitors
- Bile acid sequestrants (BAS)
- PCSK9 inhibitors
Cholesterol absorption inhibitor drugs
ezetimibe (Eztrol)
Ezetimibe mechanism
Inhibit cholesterol GI (intestinal) absorption
Ezetimibe predicted efect
Decrease LDL-C
Which 2 drugs are commonly used together?
Ezetimibe + statin
Bile acid sequestrant drugs
- cholestyramine (Questran)
- colestipol (Colestid)
Bile acid sequestrants mechanism
- promote sterol excretion
- increases LDL receptors
- bind bile acids in the GI tract and prevent their reabsorption
Bile acid sequestrants predicted effect
- decrease LDL
PCSK9 inhibitor drugs
- evolocumab (Repatha)
- alirocumab (Praluen)
PCSK9 inhibitors predicted effects
- decreased LDL
PCSK9 inhibitors mechanisms
prevent catabolism of LDL receptors
block PCSK9 action –> more LDL recycling
2 classes of drug treatment of hypertriglyceridemia
- fibrates
- nicotinic acid
Fibrates mechanism
decreases VLDL synthesis
enhances LPL action
Fibrates drugs
Gemfibrozil (Lopid)
Fenofibrate (Lipidil)
Fibrates predicted effect
decrease TG
decrease LDL-C
increase HDL-C
Nicotinic acid mechanism
decreases VLDL synthesis
increases LPL activity
Nicotinic acid drug
Nicotinic acid slow release (Quest, Niaspan)
Nicotinic acid predicted effect
decrease TG
increase HDL-C
decrease LDL
Adverse effects of statins
myalgia, myopathy, increase liver enzymes, low risk of diabetes
Which statin interacts with grapefruit juice
Simvastatin
Side effects of ezetimibe?
diarrhea, rash, fatigue, muscle weakness, pain
Contra-indications to prescribing ezetimibe
liver disease or failure
When is it recommended to prescribe ezetimibe
As a second-line tx in patients with clinical CVD and targets not reached by maximal statin dose
Side effects of bile acid sequestrants (cholestyramine)
- constipation, pain, hemorrhoids
- may decrease absorption of fat and liposoluble vitamins, Ca, Fe, Zn, Mg
Contra-indications to prescribing BAS
existing haemorrhoids, peptic ulcer, hiatus, hernia, multiple drug use, extensive travel, hypertriglyceridemia
Side effects of PCSK9 inhibitors
diarrhea, muscle or joint pain, bruising around injection site
PSCK9 =
enzyme that binds to LDL receptors and promotes their degradation (instead of LDL recycling on the cell surface)
Why is PCSK9 rarely prescribed?
expensive (7000$/y)
injectable drug
recently approved
PCSK9i recommended for who?
primary (familial) hypercholesterolemia with high LDL-C despite maximal statin dose
Side effects of fibrates (gemfibrozil)
GI reactions (taste changes, abdominal pain), muscle toxicity
Contra-indications to prescribe gembribrozil?
hepatic or renal dysfunction, gallbladder disease, combination tx with simvastatin
Fibrates prescribed for which patients?
in highly elevated TG (familial hyperTG)
Nicotinic acid side effects
Only 50-60% tolerance, GI stress, skin flushing and itching, hepatotoxicity, arrhythmias
Contraindications to prescribe nicotinic acid
active peptic ulcer, hepatic disease, gout, hyperuricemia
Nicotinic acid prescribed for which patients?
used for primary hypercholesterolemia and/or hyperTG, and hypoalphalipoproteinemia