CVD 4 Flashcards
Mechanistic effect of transfat on LDL-C and inflammation status
Sources of trans fatty acids now
↑ LDL-C and reduced LDL size (more atherogenic)
↓ HDL-C
↑ inflammatory markers and endothelial damage
Partial hydrogenation in hard margarines, processed foods
Some naturally occurring in dairy but w/o same effects
Ban in 2020 from industrial use to artificially produce trans fats
Major unsaturated fatty acids of the diet
Omega-9: oleic acid 18:1⍵9
Omega-6: linoleic acid 18:2⍵6
Omega-3:
⍺-linolenic acid 18:3⍵3
Eicosapentanoic acid (EPA) 20:5⍵3
Docosahexanoic acid (DHA) 20:6⍵3
Mechanistic effects of omega-6 PUFA consumption on LDL, HDL and inflammatory status
Results of replacing SFA w/ PUFA in diet study
↑ LDL clearance (counters suppressive effect of SFA)
↓ HDL formation/Apo-AI if >10% of total kcal (rare)
May ↑ inflammation, cancer, oxidized LDL
Consume 5-10% of total kcal in diet from corn, sunflower, safflower, soybean oils, walnuts, sunflower seeds
When ⍵-6 PUFAs replaced SFA in diet, LDL apoB-100 protein production ↓
Mechanistic effects of ⍵-9 PUFA consumption on LDL, HDL and inflammatory status
Consumption goal and sources
Advantages
↓ LDL-C vs SFA but less than ⍵-6
No change to HDL vs ⍵-6
No specific change to inflammatory status but less susceptible to oxidation vs PUFA
Goal: <20% total kcal assuming lower SFA intake from olive oil (mediterranean diet), canola oil, peanut, meat and poultry, high oleic sources of sunflower/safflower and soybean oil
Advantages:
no HDL ↓ vs PUFA/CHO, no ↑ TG vs CHO, no ↑ risk of cancer vs PUFAs
Mechanistic effects of ⍵-3 PUFA consumption on TG, CVD prevention, VLDL-TG and LDL-C
Sources
Advantages
↓ TG in hyperTG patients at high doses 2-4g
No CVD benefit in 1°/2° prevention benefit
↓ TG content of VLDL
↓ LDL-C only if replacing SFA in diet
Sources: fish (EPA/DHA) and canola/linseed/soybean oil (ALA)
Advantages:
Prevent coronary thrombosis through interfering with platelet aggregation and delayed fibroblast proliferation
Reduced plaque formation by ↓ adhesion molecules
Fiber mechanistic effect on LDL, benefits, goal and sources
↓ total-C and LDL-C dependent on hypercholesterolemia level
↓ energy and fat intake
Goal: 20-30g/day, 50% soluble fiber
Sources: oats, legumes, pectins, psyllium and gums
Mechanistic effect of simple CHO on serum cholesterol and blood glucose regulation
Excess sucrose, fructose and HFCS ↑ VLDL-TG production
↑ TG and hyperTG in some populations
↓ HDL-C
↑ BG and hyperinsulinemia
Alcohol effects on HDL-C and TG
Mechanism behind french paradox
↑ HDL-C
⊣ acyl-coA oxidation in liver (avoid drinking if hyperTG) and not recommended for those with established CHD
1-2/d is ok to drink
Red wine ⊣ cell-mediated oxidation of lipoproteins due to resveratrol (polyphenol) and may explain French paradox (other factors too)
Action of antioxidants on LDL oxidation
Unconfirmed benefits of vit C, vit E and β-carotene individually for CHD
⊣ LDL oxidation and ↓ atherosclerosis risk
Homocysteine normal fasting levels and levels which increase risk of heart disease
Prevalence and intervention data
Normal fasting = 6-12 µmol/L
Elevated = > 14 µmol/L –> ↑ risk of heart disease
5 µmol/L ↑ incidence of CVD by 1.6-1.8x
Hyperhomocysteinemia 1:70 prevalence and 40% of CVD patients
Randomized trials do not support effect of homocysteine-lowering interventions for MI prevention, possible benefit for stroke prevention
B12, folate and B6 importance in homocysteine metabolism
B12/folate required to convert homocysteine –> methionine
Folate deficiency associated with high homocysteine
B6 required to convert homocysteine –> cystathione
Recommendations:
↑ food sources of folate: fortified cereals, veg, citrus, legumes and organ meats
Supplement 500 µg folate/d (if no B12 deficiency) if high homocysteine or family history of CVD
Phytosterols/stanols mechanism of cholesterol effect, recommendation and source
Plant cholesterol compete w/ cholesterol absorption to ↑ fecal excretion
Recommendation: 2-2.5g sterols ↓ LDL-C by 6-14%
Source: fortified margarines only way to achieve this amount
Benefits of nuts on CVD risk
Rich in MUFA/PUFA, low in SFA
High in protein, soluble fiber, folic acid, antiox, and arginine
30-60g/d ↓ risk of CHD and ↓ LDL-C and improves endothelial function
No effect on BW
What ↑ HDL-C, what ↓ HDL-C?
↑ HDL-C
Main: SFA, dietary cholesterol, alcohol ≤ 2/d
Other: long term aerobic exercise, estrogens and female sex
↓ HDL-C
Main: simple sugars/high carb diet, PUFA >10%, abdominal obesity
Other: androgens, male sex, anabolic steroids, antihypertensive drugs, T2M, cigarettes
US Dietary approach for dyslipidemia
Target ranges for SFA, trans fat, PUFA, MUFA, total lipids, cholesterol, CHO, fiber total and soluble, protein and sterols/stanols
Target LDL-C reduction, then factors of MetS
Therapeutic lifestyle changes:
↓ SFA,↑ PA, Weight management to ↓ coronary risk
SFA: < 7% (including transfats - avoid)
PUFA: ≤ 10% and ↑ ⍵-3 from fish
MUFA: ≤ 20%, replace SFA
Total lipids: 25-35% of E (US) or <30% (Canada)
Cholesterol: <200 mg for dyslipidemia/high risk people
CHO: 50-60% of E, ↓ refined sugar and choose whole grains
Fiber total: 20-30g/d, ↑ F&V
Fiber soluble: 10-25g/d
Protein: 15% of E, ↑ soy protein and nuts to replace animal protein
Sterols/stanols: 2g/d, ↑ intake
Results of PREDIMED trial on mediterranean diet vs low-fat control
30% ↓ in CV events + good lipid profile vs low-fat diet
↓ LDL-C, apo-B and TG with ↑ HDL-C
No adverse effects
Other studies show additive effects to statins and ↓ 70% in mortality post-MI for secondary prevention
Porfolio diet characteristics and study results
Drawbacks to portfolio
Canada’s Food Guide adherence results in UK biobank study
Characteristics: low sat fat, high phytosterols 1g margarine, soy protein 21g, soluble fibers 10g and almonds 14g
↓ LDL-C, ↓ CRP vs low fat control
Drawbacks: poor adherence, 40-45% only
CFG adherence: 9-32% ↓ RR of major CVD
Diet therapy for: extreme high TG, blood cholesterol, severe type V hyperlipidemia
Extreme high TG:
1) ideal body weight
2) 10-15% E from fat (20-30g/d) + MCT oil as needed
3) ↓/eliminate simple sugars
4) No alcohol
Blood cholesterol
1) Ideal BW
2) ↓ total fat (replace SFA w/ PUFA) and ↓ cholesterol
Severe type V hyperlipidemia
1) ↓ total fat to 20% of total E
2) Eliminate sugar and alcohol
