Fatty acids
17 important questions on Fatty acids
4 types of biomedical studies in nutrition research and its strengths and limitations
- Randomized, controlled
- Validity of marker
Epidemiology (observational)
- Hard end-point
- Real life situation
- Confounding
Clinical trails (RCT) on disease endpoints
- Hard end-point
- Randomised
- Duration, patients
In vitro, animals
- Mechanism
- Insight
- Extrapolation
Influence of diet on Cardiovascular risk
- A multi-factorial disease, multiple risk factors contribute to its development & progression
- Diet can influence CVD risk in many ways
- Much evidence available for effects via blood lipids on coronary heart disease
The fat absorption in the intestine/gut
- Food
- Gut lumen
- Gut wall
- Lymph and blood
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5 different types of lipids ingested from the diet
- Triglycerides (triacylglycerol): >95% of intake
- Fat-soluble vitamines
- Phospholipids
- dietary cholesterol *
- Plant sterols
*about 1/3 of cholesterol that enters the gut comes from the diet, 2/3 comes from bile
Transport of lipids to and from peripheral tissues
What is the structure and classification of lipoproteins
Small dense LDL particles are considered more pro-atherogenic than large LDL particles
- Decreased affinity for LDL-R
- Increased ability to enter the arterial wall
- More susceptible to oxidation and enhanced uptake by macrophages
How can you divide the blood lipids?
- LDL and HDL are cholesterol-rich particles
- LDL is BAD
- HDL is GOOD
- Chylo and VLDL are triglycerides (TG)-rich particles
- LDL, Chylo and VLDL together are the atherogenic particles
LDL-C is an established causal CHD risk factor. What does elevated plasma/serum LDL-cholesterol concentrations cause?
- Strongly associated with arterosclerosis and CHD risk
- Convincing evidence from different types of studies: animal experiments, randomised clinical trails, observations studies, and 'mendelian randomization'
- Cornerstone of dyslipidemia therapy
- 10% lowering in LDL-cholesterol --> 7% reduction in CHD mortality
What is told about the plasma HDL-concentration in CVD risk?
- low HDL-C linked to higher CVD risk
Intervention studies
- No evidence that increasing HDL-C may lower CVD risk
HDL concentration is an independent risk predictor but not an independent risk factor
Can you tell more about: " Not the plasma concentration of HCL, but rather its functionality may be important
- HDL-C is a biomarker of CVD risk, not a causal risk factor
- Functionality of the HDL particle may exert different cardio-protective effects, but this needs to be further established
- Reverse cholesterol transport is a likely mechanism
Plasma triglycerides and CHD risk
- Plasma TG concentration is an aggregate measure of TG in all circulating lipoproteins
- Plasma TG is strongly associated with cholesterol in smaller lipoprotein remnant particles
Two types of Phytosterols in our diet
Plant stanols
- Plant sterol intake with habitual diets: 200-300 mg/d, with vegetarian-type, plant-based diets: 400 mg to 1 g/d
- Plant stanol intake with habitual diets: 25-50 mg/d
The cholesterol-lowering effect oh phytosterols
with average phytosterol intake of 2.15 g/day
Why is fat a key component of a healthy diet?
- Macronutrient, provides energy
- Provides essential fatty acids (omega-3 and 6)
- Is a carrier of fat-soluble vitamins
- Adds taste and flavour to our foods
- Dietary fatty acids influence the risk of heart disease
Different types of fats in the diet
- PUFA
- Omega-6
- AA
- Omega-3
- EPA
- DHA
- MUFA
- SAFA
- TFA
The concept of iso-caloric replacement
- Fat delivers calories. When fat intake changes, intake of one or more other calorie-delivering macronutrient(s) must change as well to keep energy-balance
- Effects of a macronutrient are always relative, they depend on the other macronutrient(s) being replaced
Effect of a fatty acid is usually expressed relative to carbohydrates. Can equally be expressed as replacing another fatty acid
What replacement of SAFA is most effective for improving the blood lipid risk profile?
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