Triglycerides Phospholipids Sterols The Lipids Triglycerides Phospholipids Sterols

Lipids Triglycerides (TG) Fats and oils Phospholipids Sterols

Fatty Acids (FA) & TG glycerol-a sugar alcohol, backbone of a FA! REM: they have carbon (C), so they are organic!

FA & TG glycerol + 3 FA TG + H2O

Condensation of Glycerol & Fatty Acids to Form a Triglyceride

Fatty Acids Length (size matters) Saturated vs. unsaturated Acetic Acid (most simple)

Saturated Fatty Acids How many carbons? Stearic acid – 18-carbon Simplified structure

Fatty Acids Point of saturation (where?) Degree of saturation (how much?) Saturated fatty acid Monounsaturated Polyunsaturated

An impossible chemical structure: Why? Oleic acid – 18-carbon, monounsaturated Linoleic acid – 18-carbon, polyunsaturated

OMEGA NUMBER: Ω-3 vs. Ω-6 Fatty Acids

TG: Why Does Saturation Matter? Unsaturation effects: Firmness Stability Oxidation Antioxidants

Triglycerides:What about “hydrogenated oils?” Hydrogenation-hydrogen added to mono- or polyunsaturated fats to make them solid by reducing the number of double bonds (C=C). Cis vs. trans-fatty acids

Hydrogenation

Cis- and Trans-Fatty Acids Compared So what? It’s a nice picture.

Trans fats are bad!!! In the body trans fats behave like saturated fats! Why? They contribute to higher LDL cholesterol and lower levels of "good" HDL cholesterol = heart disease.

Phospholipids

Phospholipids (PL) Phospholipids in foods Roles of PL Plasma membrane Emulsifiers (help oil and water exist together)

Membrane Structure PL Hydrophobic tail vs. hydrophilic head: more on this later.

Sterols

Sterols Roles of sterols: Good Bile acids Sex hormones Adrenal hormones Vitamin D Roles of sterols: Bad -Atherosclerosis-hardening of arteries.

Fat Digestion Yummy...or not.

Fat Digestion Hydrolysis Triglycerides  monoglycerides, fatty acids, glycerol

Fat Digestion

Fat Digestion Mouth Melting Lingual lipase

Fat Digestion Stomach Churning and mixing Gastric lipase

Fat Digestion Small intestine CCK-hormone which signals bile release! Bile emulsifies fats.

Fat Digestion

Fat Digestion

Fat Digestion Small intestine Pancreatic lipases Intestinal lipases

Fat DigestionOverview

Fat Digestion Enterohepatic circulation Note how fiber helps remove excess cholesterol!!

Lipoproteins and health Factors that lower LDL and raise HDL Weight control Replace saturated fat with monounsaturated fat and polyunsaturated fat in the diet Soluble fibers Phytochemicals Moderate alcohol consumption Physical activity (biggest helper) Genes influence lipoprotein activity.

Roles of Triglycerides Fat stores Energy Protection Insulation

Essential Fatty Acids

Fat Metabolism

Storage as fat Adipose tissue LPL = lipoprotein lipase...fat storage.

Lipid Metabolism Using fat for energy Hormone-sensitive lipase...triglyceride release. Provides very little glucose...problem during fasting?

Health Effects of Lipids Blood lipid profile Heart disease Risks from saturated fats

Health Effects of Lipids:US Diet

Dietary Cholesterol

Health Effects of Lipids Benefits:monounsaturated and polyunsaturated fats Cancer Obesity

Health Effects and Recommended Intakes of Lipids Recommended Intakes of Fat DRI: 20-35% of energy intake (400-700 kcalories of a 2,000-kcal diet). FDA recommends 10% of energy intake from s Linoleic acid AI Linolenic acid AI 5-10% of energy intake 0.6-1.2% of energy intake aturated, 30% of energy intake total fat

Health Effects and Recommended Intakes of Lipids Daily Values 65 g fat based on 30% of 2000-kcal diet 20 g sat. fat based on 10% of 2000-kcal diet 300 mg cholesterol USDA Food Guide considers saturated fats discretionary kcalories. Too little fat can be detrimental to health.

Health Effects and Recommended Intakes of Lipids Health Effects of Lipids Blood lipid profile Reveals concentrations of lipids in the blood Desirable levels Total cholesterol < 200 mg/dL LDL cholesterol < 100 mg/dL HDL cholesterol ≥ 60 mg/dL Triglycerides < 150 mg/dL

Cutting Fat Cuts kCalories and Saturated Fat

Guidelines to Groceries Milk and milk products Vegetables, fruits, and grains Invisible fat

High-Fat Foods Changing guidelines for fat intake

High-Fat Foods Cook with olive oil Nibble on nuts Feast on fish But beware of mercury?

High-Fat Foods Mediterranean diet?