Dietary Fats

Dietary fats include: triglycerides (TAG), phospholipids, and cholesterol

• most strongly influence the incidence of coronary heart disease (CHD)
• in causing disease, type of fat is more important than the total amount of fat consumes

Plasma Lipids and Coronary Heart Disease (CHD)

Plasma lipids may arise from:

• the diet
• endogenous biosynthesis

Low-density and high-density lipoprotein

• elevated levels of total cholesterol (hypercholesterolemia) = increased risk for CHD
• low-density lipoproteins (LDL-C) increases = CHD increases
• elevated high-density lipoprotein cholesterol (HDL-C) levels = decreased risk for heart disease

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CHD Risk Factors

• abnormaln levels of plasma lipids (dyslipidemias)
• smoking
• obesity
• sedentary lifestyle
• insulin resistance

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Benefits of Lowering Plasma Cholesterol

• decreasing LDL-C
• increasing HDL-C
• reducing risk for cardiovascular events

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Dietary Fats and Plasma Lipids

• TAG most important class of dietary fats

Structural features that influence blood lipids:

• absence or presence and number of double bonds (saturated, mono- polyunsaturated)
• location of double bonds
• cis or trans configuration of unsaturated fatty acids

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Saturated Fats

• do not contain double bonds
• typically solid at room temperature
• ^^associated with:^^
  • high levels of total plasma cholesterol and LDL-C
  • ==increased risk of CHD==
• ^^main sources:^^ dairy and meat products, some vegetable oils (e.g. coconut and palm oils)
• intake should be limited to ==less than 10%== of total calories in diet

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Monounsaturated Fats (MUFA)

• contain one double bond
• ^^main sources^^: plant-based oils
• when substituted for saturated fatty acids in the diet:
  • lower total plasma cholesterol
  • lower LDL-C
  • maintain or increase HDL-C
• intake should constitue to ==more than 10%== of total calories in diet

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The Mediterranean Diet

• example of a diet rich in MUFA (from olive oil) and polyunsaturated fatty acids (PUFA) (from fish oils, plant oils, and some nuts)
• low in saturated fat
• ^^contains^^:
  • seasonally fresh food
  • abdunacne of plant material
  • low amounts of red meat
  • olive oil (main source of fat)
• ^^associated with^^:
  • decreased plasma total cholesterol
  • decreased LDL-C
  • increased HDL-C

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Polyunsaturated Fats (PUFA)

• contain more than one double bond
• effects of PUFA on cardiovascular disease are influenced by location of double bonds
  • ω-6 fatty acids (n-6 fatty acids):
  • long chain PUFA
  • lower plasma cholesterol
  • LDL-C and HDL-C lowered
  • ^^main sources^^: nuts, avocados, olives, soybeans
  • ω-3 fatty acids:
  • long chain PUFA
  • suppresses cardiac arrhythmia
  • reduce plasma TAG
  • decrease tendency for thrombosis
  • lower blood pressure
  • reduce risk of cardiovascular mortality
  • ^^main sources^^: plant oils and some nuts
  • ==Docosahexaenoic acid (DHA)== is an omega-3 fatty acid added in infant formulas to promote brain development

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Trans Fatty Acids

• chemical classification: unsaturated fatty acids
  • behave more like saturated fatty acids
• elevate LDL-C
• lower HDL-C
• increase risk of CDH
• formed during hydrogenation of vegetable oils

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Dietary Cholesterol

• only in animal products
• recommended amount: ==less than 200 mg/day==

Plant Sterols

• ^^main sources^^: plant sources (e.g. broccoli) and some margarines
• reduce LDL-C by interfering with the absorption of dietary cholesterol

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