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Fat Dietary fats:
Polyunsaturated fatty acids Monounsaturated fatty acids Saturated fatty acids
Cholesterol It is recommended that dietary saturated
fat intake be <7% of energy to reduce CHD risk
Fat Dietary fats and cholesterol play a major
role in CHD development Saturated fatty acids: contain no double
bonds and generally vary in chain length from 12 to 18 carbons.
Major sources of saturated fat in diet: dairy, beef, pork, poultry, and lamb products
Saturated Fatty Acids Saturated fatty acids increase LDL-
cholesterol concentrations by decreasing LDL receptor–mediated catabolism
This effect is mediated both by decreased LDL receptor messenger RNA (mRNA) expression and decreased membrane fluidity
This latter effect causes less receptor recycling across the cell membrane.
It is recommended that dietary saturated fat intake be <7% of energy to reduce CHD risk
Monounsaturated fatty acids
The major monounsaturated fatty acid in the diet is oleic acid, which contains one double bond at the number 9 carbon
Monounsaturated fatty acids, as compared with dietary carbohydrates, were neutral with respect to their effects on plasma total cholesterol concentrations
When substituted for dietary saturated fatty acids, monounsaturated fatty acids have a hypocholesterolemic effect
Monounsaturated fatty acids
Monounsaturated fats do not lower LDL or HDL cholesterol relative to saturated fat as much as does polyunsaturated fat
Food sources: olive oil, peanut oil, margarine, chicken fat
Trans Fatty Acids Trans Fatty acids are formed during the
hydrogenation process, a process that converts vegetable oils to a semisolid state
Major sources: baked products, processed foods, and margarines
Increases plasma concentrations of lipoprotein(a), an independent risk factor for CHD
Polyunsaturated fatty acids
Subclassified: n−6 and n−3 The major n−6 fatty acid in the diet is α-
linoleic acid, the precursor for arachidonic acid (20:4n−6)
α-Linoleic acid is not synthesized by the body and is therefore an essential fatty acid.
Food sources: vegetables and vegetable oils (corn, soybean, safflower, and sunflower), with the exception of coconut and palm oils
Ω-3 fatty acid linolenic acid (18:3n−3) hypocholesterolemic effect: reducing both LDL-
and HDL-cholesterol concentrations, lower platelet aggregation, lower immune response, and lower blood pressure
fish oil, especially eicosapentaenoic acid, lower triacylglycerol concentrations significantly
recommended that the polyunsaturated fat intake be <10% of energy
An optimal ratio of n−6 to n−3 fatty acids in the diet is believed to be ≈4:1.
Cholesterol 1.3 egg yolks/d containing 272 mg
cholesterol increases LDL cholesterol Cholesterol with saturated fat, should be
restricted in the diet to ≤200 mg/d to decrease CHD risk
National Cholesterol Education Program coronary heart disease (CHD) risk factors- NCEP in addition to diabetes and elevated LDL cholesterol1
1Subtract one risk factor for HDL cholesterol ≥ 1.6 mmol/L (60 mg/dL). Diabetes has been defined as a CHD risk equivalent.2Defined as CHD in a male first-degree relative aged <55 y or a female first-degree relative aged <65 y.
1) Male ≥45 y
2) Female ≥55 y
3) Family history of premature CHD2
4) Hypertension
5) Cigarette smoking
6) HDL cholesterol <1.0 mmol/L (40 mg/dL)
National Cholesterol Education Program guidelines on dietary therapy(Am J Clin Nutr February 2002 vol. 75 no. 2 191-212)
Nutrient Average US diet2
Therapeutic lifestyle changes
Saturated fat (% of energy) 12 <7
Monounsaturated fat (% of energy) 13 <20
Polyunsaturated fat (% of energy) 7 <10
Cholesterol (mg/d) 270 <200
Total energy —To achieve and maintain a desirable body weight
Carbohydrate (% of energy) 51 50–60
Protein (% of energy) 15 15
Hypertension Calcium, potassium, magnesium,
phosphorus, and fiber that would be included in a diet containing adequate amounts of dairy products and fruit and vegetables.
Reduce salt intake (< 5 g/day) Maintenance body weight