The Lipids: Fats & Oils Chapter 5

A Primer on Fats The functions of fats in the body The functions of fats in foods

A Closer View of Fats Saturated vs. unsaturated fats The essential fatty acids Linoleic acid & linolenic acid Omega-6 vs. omega-3 fatty acids

Characteristics of Fats in Foods Firmness/melting properties Preventing spoilage Hydrogenation Increases degree of saturation Antioxidant additives Emulsifier additives

The Other Members of the Lipid Family: Phospholipids & Sterols Phospholipids Lecithin Sterols Cholesterol

How the Body Handles Fat Digestion Absorption Chylomicrons - type of lipoprotein Lipoproteins Low-density lipoproteins (LDL) High-density lipoproteins (HDL)

“Good” vs. “Bad” Cholesterol Atherosclerosis Narrowing of arteries due to cholesterol- containing plaque build-up Oxidized LDL-cholesterol (o-LDL) Foam cells LDL = bad HDL = good

Fat in the Diet DGA: total fat - 20%-35% of calories Saturated fat - <10% of calories Replace saturated fat with monounsaturated But control total energy intake Visible vs. invisible fat

Oh, Nuts! You Mean Fat Can Be Healthy? When more fat might be better Mediterranean diet = 30%-35% of calories from fat What’s so special about olive oil? High in monounsaturated oleic acid Something’s fishy here! Oily fish are high in omega-3 fats

Oh, Nuts! You Mean Fat Can Be Healthy? Nuts to you! Omega-3 sources: soybeans, pecans, walnuts, & flaxseed What’s your meal mentality? Slower-paced meals in pleasant environment

The Trans Fatty Acid Controversy-- Is Butter Better? Trans fats raise LDL & lower HDL Hydrogenation results in trans fats Trans fats must be listed on food labels as of January 2006 “Trans fat free” = <0.5 g/serving Butter is not better You should avoid sat. & trans fats

Understanding Fat Substitutes Fat-reduction ingredients Egg whites, nonfat milk Starches, gums, & gels Fat substitutes Simplesse Olestra

Choosing Fats Sensibly Use nonstick sprays Reduce fat in recipes gradually Reduce oils used for sautéing Refrigerate broths to skim off fat Prepare lean cuts of meat & trim visible fat Use herbs, spices, & other seasonings Use fruit jams or whipped spreads

Nourish the Heart Become a savvy supermarket shopper Read food labels

Nourish the Heart Keep blood cholesterol at or below the recommended levels Replace saturated fats with monounsaturated & polyunsaturated Replace sat. & trans fats with unsaturated from healthful foods Add fiber Increase fruit & vegetable intake

Nourish the Heart Balance energy intake with energy needs Maintain healthy body weight Keep physically fit At least 30 minutes of moderate exercise per day

Diet & Heart Disease No one is free of atherosclerosis Increases blood pressure Restricts blood flow Risk factors for atherosclerosis Modifiable vs. non-modifiable High LDL/low HDL = strong correlation with heart disease

Diet & Heart Disease To reduce total & LDL-cholesterol: Reduce saturated & trans fat intakes Plant stanols or sterols Cholesterol: <300 mg/day HDL increased by: Female gender Not smoking Regular exercise

Diet & Heart Disease Homocysteine Product of protein breakdown High levels linked to heart disease & strokes Moderate alcohol intake protective Garlic may be beneficial Evidence is conflicting