The Good the FAT the Ugly Pauline Williams

The Good, the FAT, & the Ugly Pauline Williams, MPA, RD, CD Nutrition and Food Science Workshop 2008

The body needs fat Insulation Protection Energy Storage Muscle fuel Hormone Synthesis Nerves Cell Membranes

Fats look and act different in the body Number of carbons in chain – Short, medium, or long Placement and number or double bonds Structure – chain, round, bent

Fatty Acids

Saturated versus Unsaturated Fatty Acids Saturated fatty acid – filled to capacity with hydrogen atoms Unsaturated fatty acid – missing hydrogen – Monounsaturated – one point of unsaturation – Polyunsaturated – two or more points of unsaturation (PUFA)

Saturated Fats C C C C C solid at room temperature – Exception: coconut and palm oil Usually from animal sources – lard, butter, bacon, fatty red meat, cream, chocolate, cream cheese, sour cream high intake – increase risk for heart disease C Acid C

Monounsaturated C C C C Acid C C C liquid at room temperature, cloudy in fridge Food sources – Avocado – Nuts (almonds, cashews, hazelnuts, peanuts, pecans, pistachios) – Oil (olive, canola, peanut, sesame) – Olive may be protective against heart disease

Polyunsaturated C C C C Acid C C C liquid at room temperature plant sources – soy, safflower, corn oils, nuts may decrease risk for heart disease

Omega-3, Omega-6 fatty acids types of polyunsaturated fats Essential fats need in diet C C Ω C C 1 2 C C C 4 3 C 5 6 C C 7… C 2 3 C 1 4 C C 5 6 C C 7… C C id Ac C Ω Acid C

Omega 6 fats Linoleic acid omega-6 – Margarine – Mayonnaise, salad dressing – Nuts (walnuts) – Oils (corn, safflower, soybean) – Seeds (pumpkin, sunflower)

Omega 3 fats Linolenic acid omega-3 – Fatty fish (salmon, tuna) – Flax seed – nuts – Linolenic acid can be converted to EPA and DHA

EPA and DHA EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) – lower blood pressure – prevent blood clot formation (large amounts may cause bleeding, bruising) – protect against irregular heartbeats – may reduce inflammation – essential for normal infant growth and development – may support immune system – may inhibit cancers

How much Omega-3? For health benefits balance between omega 3 and omega-6 fatty acids – Americans get mostly omega-6 from • vegetable oils, salad dressings, and margarine and – Americans need more omega-3 • Fish 2 times a week • Average U. S. intake of EPA and DHA is 150 mg/day • Recommended is 500 mg/day (about 2 fatty fish meals per week)

Hydrogenation Adds Hydrogen C H C C C Acid More saturated C C H H C C H C H C C H H C C C H H Acid C H

Trans-fatty acids Trans double bond C C C C Acid H C C C C H C id Ac C Cis double bond C

Trans fatty acids Affects blood cholesterol similar to saturated fat Soft or solid at room temperature Created when oils are hydrogenated What foods have them? (Processed) – Baked goods (cookies, pie, cakes) – Fried foods (especially fast food) – Margarine – Processed snacks, crackers, chips, microwave popcorn

Looking at the label One serving crackers No trans fat 30% daily limit saturated fat

Why Hydrogenate? Reduce rancidity and increase shelf life Change to more solid texture – spreads more easily – makes baked goods flaky and tender

Butter or Margarine Soft or liquid margarines – made from unhydrogenated oils – mostly unsaturated Solid margarine – Hydrogenated oils Butter – Saturated fat Choose any sparingly

Types of fat in oils

Saturation continuum More saturated Beef fat Stick margarine Tropical oils (exception to the rule) Chicken fat (less solid) Tub margarine Squeeze margarine Less saturated Fish oils (exception to the rule) Vegetable oils

Cholesterol/Lipid Transport Lipoproteins Chylomicrons (mostly fat; neutral for risk CVD) VLDL=very low density lipoprotein LDL =low density lipoprotein HDL=high density lipoprotein

Good and Bad Cholesterol LDL – “lousy” – Higher LDL increase risk for heart disease HDL – “Healthy” – Higher HDL protective against heart disease

Cholesterol effect Diet Saturated fat and Trans fat – Increases LDL, decreases HDL Polyunsaturated fat – Decreases LDL, decreases HDL Monounsaturated fat – Decreases LDL, keeps HDL same Cholesterol intake (very little impact)

Cholesterol effect other Genetics Health behaviors – Smoking – Exercise can help lower LDL and raise HDL

Fats and Healthy Eating 20 -35% calories from fat Limit saturated and trans-fat – Less solid fat Choose oils not solids fat – Monounsaturated fat – omega-3 fats (good sources 2 -3 times/weei) Minimize cholesterol intake – Not a large effect on heart disease

How many grams/day? 20 -35% of total kcals = fat kcals 2000 kcals x. 20 = 400 fat kcals 2000 kcals x. 35 = 700 fat kcals Fat kcals / 9 = fat grams 400 kcals / 9 = 44 g fat 700 kcals / 9 = 78 g fat

Fat Replacers Olestra – most common – Not digested – Sucrose polyester (fatty acid bonded to a sugar) – Mimics texture and quality of fat Whip air or water into product to decrease fat Use less fat – May add carbohydrate to get texture

Pros and Cons of Olestra

Questions?