Lipids: Fats and Oils All Food Fats Were Not Created Equal!

Lipids: Fats and OilsLipids: Fats and Oils

All Food Fats Were Not Created All Food Fats Were Not Created Equal!Equal!

Classification of LipidsClassification of Lipids

Triglycerides-A glycerol and 3 fatty acidsTriglycerides-A glycerol and 3 fatty acids• Saturated Fatty acidsSaturated Fatty acids-carries maximum number of -carries maximum number of

hydrogen atomshydrogen atoms

• Unsaturated Fatty AcidsUnsaturated Fatty Acids-one or more points of -one or more points of unsaturation occurunsaturation occur

– Monounsaturated (MUFA)-contains one point of unsaturationMonounsaturated (MUFA)-contains one point of unsaturation

– Polyunsaturated (PUFA)-contains two or more points of Polyunsaturated (PUFA)-contains two or more points of unsaturationunsaturation

– Omega 6 (linoleic)-leafy veggies, seeds, nuts, grains, oilsOmega 6 (linoleic)-leafy veggies, seeds, nuts, grains, oils

– Omega 3 (linolenic)- oils, nuts, seeds, soybeansOmega 3 (linolenic)- oils, nuts, seeds, soybeans

Classification (con’t)Classification (con’t)

PhospholipidsPhospholipids-similar to a triglyceride, but having -similar to a triglyceride, but having

a phosphorus-containing acid in place of one of a phosphorus-containing acid in place of one of

the fatty acids (lecithin)the fatty acids (lecithin)

SterolsSterols-most common is -most common is cholesterol, which is a , which is a

soft waxy substance made by the liver and found soft waxy substance made by the liver and found

in animal foods, but not an essential nutrientin animal foods, but not an essential nutrient

Lipid StructuresLipid Structures

The Fatty AcidsThe Fatty Acids

Fatty Acid Structure Fatty Acid Structure (Fig. 5-1-A)(Fig. 5-1-A)

omega end alpha

end degree of saturation

H H H H H H H H H H H H H H H H H O

H-C--C--C--C--C--C--C--C--C--C--C--C--C--C--C--C--C--C-OH

H H H H H H H H H H H H H H H H H

Saturated Fatty Acid Structure Saturated Fatty Acid Structure (Fig. 5-1-A)(Fig. 5-1-A)

omega end alpha

end degree of saturation: single carbon

bond


H-C--C--C--C--C--C--C--C--C--C--C--C--C--C--C--C--C--C-OH


Monounsaturated Fatty Acid Monounsaturated Fatty Acid Structure Structure (Fig. 5-1-B)(Fig. 5-1-B)

omega end alpha

end One double bond

H H H H H H H H H H H H H H H O

H-C--C--C--C--C--C--C--C--C=C--C--C--C--C--C--C--C--C-OH


Polyunsaturated Fatty Acid Polyunsaturated Fatty Acid Structure Structure (Fig. 5-1-C)(Fig. 5-1-C)

omega end alpha

end > 2 double bonds

H H H H H H H H H H H H H O

H-C--C--C--C--C--C=C--C--C=C--C--C--C--C--C--C--C--C-OH


Carbon Chain Length of Fatty Carbon Chain Length of Fatty AcidsAcids

Long chain FA Long chain FA • >> 12 Carbons 12 Carbons

Medium chain FAMedium chain FA• 6 - 10 Carbons6 - 10 Carbons

Short chain FAShort chain FA• << 6 Carbons 6 Carbons

Comparing Dietary FatsComparing Dietary Fats

Healthful OilsHealthful Oils

Fat in the USDA PyramidFat in the USDA Pyramid

Processed Fats and Processed Fats and HydrogenationHydrogenation

Hydrogenation is adding hydrogen atoms Hydrogenation is adding hydrogen atoms under pressure to solidify an oilunder pressure to solidify an oil

Forms trans fatty acidsForms trans fatty acids Try to avoid hydrogenated and partially Try to avoid hydrogenated and partially

hydrogenated fats in foodshydrogenated fats in foods• Increases blood cholesterol levelsIncreases blood cholesterol levels• Decrease HDL’s and increases LDL’sDecrease HDL’s and increases LDL’s

Check labels (i.e.margarines)Check labels (i.e.margarines)

Minimize Intake of Trans Fatty Minimize Intake of Trans Fatty AcidAcid

Limit use of hydrogenated fatsLimit use of hydrogenated fats Limit deep-fried foodsLimit deep-fried foods Limit high fat baked goodsLimit high fat baked goods Limit use of non-dairy creamersLimit use of non-dairy creamers

RancidityRancidity

Decomposed oilsDecomposed oils Breakdown of the C=C double bonds by Breakdown of the C=C double bonds by

ultraviolet rays, Oultraviolet rays, O22

Yields unpleasant odor and flavorYields unpleasant odor and flavor PUFA more susceptible PUFA more susceptible Limits shelf lifeLimits shelf life

Prevention of RancidityPrevention of Rancidity

Hydrogenation (Not recommended)Hydrogenation (Not recommended) Addition of vitamin EAddition of vitamin E Addition of Butylated hydroxyanisol (BHA) Addition of Butylated hydroxyanisol (BHA)

and Butylated hydroxytolune (BHT)and Butylated hydroxytolune (BHT) RefrigerateRefrigerate Consume in a reasonable timeConsume in a reasonable time

Digestion and Absorption of FatsDigestion and Absorption of Fats

DigestionDigestion• Liver makes bileLiver makes bile

• Gallbladder stores bile, then Gallbladder stores bile, then releases into small intestinereleases into small intestine

• Bile Emulsifies fatBile Emulsifies fat

• Pancreas releases enzyme Pancreas releases enzyme Lipase splitting splitting triglycerides into triglycerides into Monoglycerides, Glycerol, Monoglycerides, Glycerol, and FAand FA

AbsorptionAbsorption• Monoglycerides, Glycerol, Monoglycerides, Glycerol,

and FA absorbed through and FA absorbed through wall of small intestinewall of small intestine

• Smaller fats absorbed into Smaller fats absorbed into blood and carried as blood and carried as lipoproteinslipoproteins

• Larger fats absorbed into Larger fats absorbed into lymphatic system as lymphatic system as chylomicronschylomicrons

Fat Digestion and AbsorptionFat Digestion and Absorption

Functions of FatFunctions of Fat Stores energyStores energy Cushion vital organsCushion vital organs Insulates the body and maintain body temperatureInsulates the body and maintain body temperature Transports essential fatty acids and fat soluble Transports essential fatty acids and fat soluble

vitaminsvitamins Part of cell membrane structurePart of cell membrane structure Offers satiety in mealsOffers satiety in meals Enhances food flavor and aromaEnhances food flavor and aroma

Metabolism of LipidsMetabolism of Lipids

Chylomicrons Transport dietary fat

VLDL Transport lipids made by the liver

Metabolism of LipidsMetabolism of Lipids

Lipoprotein CarriersLipoprotein Carriers• High-density LipoproteinsHigh-density Lipoproteins

– Contains a large percentage of proteinContains a large percentage of protein

– Returns cholesterol from storage places to the liver for Returns cholesterol from storage places to the liver for dismantling and disposal dismantling and disposal

– ““Good cholesterol”Good cholesterol”

• Low-density LipoproteinsLow-density Lipoproteins– Contains a large percentage of cholesterolContains a large percentage of cholesterol

– Transfers lipids from liver to tissuesTransfers lipids from liver to tissues

– ““Bad cholesterol”Bad cholesterol”

Structures of LipoproteinsStructures of Lipoproteins

How much Fat Do We Need?How much Fat Do We Need?

RequirementsRequirements• 3% of Calories from 3% of Calories from

linoleic acidlinoleic acid

• .3% of Calories from .3% of Calories from linolenic acidlinolenic acid

RecommendationsRecommendations• Govt. Recs.Govt. Recs.

– No more than 30% total No more than 30% total fat, < 65 grams/dayfat, < 65 grams/day

– No more than 10% No more than 10% saturated fatsaturated fat

– Less than 300mg from Less than 300mg from cholesterolcholesterol

• WHO Recs.-WHO Recs.-lower limit 0%lower limit 0%

• McDougall, Ornish, Pritikin McDougall, Ornish, Pritikin Recs.Recs.

– 10-15% total fat10-15% total fat

Essential Fatty AcidsEssential Fatty Acids

Body can’t make itBody can’t make it Needed for immune function, vision, Needed for immune function, vision,

cell membrane, and production of cell membrane, and production of hormone-like compoundshormone-like compounds

Essential Fatty Acid- Omega-3 (alpha-Essential Fatty Acid- Omega-3 (alpha-linolenic acid)linolenic acid)

omega end alpha

end 1st double bond is located on the 3rd

carbon from the omega end


H-C--C--C=C--C--C =C--C--C=C--C--C--C--C--C--C--C--C-OH

H H H H H H H H H H H

Omega-3 Fatty AcidOmega-3 Fatty Acid

Primarily from fish, canola, and soybean oilPrimarily from fish, canola, and soybean oil Found also in flax seeds and walnutsFound also in flax seeds and walnuts Eicosapentaenoic acid (EPA) and Eicosapentaenoic acid (EPA) and

docosahexaenoic acid (DHA) are related docosahexaenoic acid (DHA) are related Metabolized to form eicosanoidsMetabolized to form eicosanoids Recommended to eat fish 1-2 x per week or Recommended to eat fish 1-2 x per week or

consume the plant sources givenconsume the plant sources given Decreases blood clot formationDecreases blood clot formation Lowers risk of heart diseaseLowers risk of heart disease

Essential Fatty Acid- Omega-6 (alpha-linoleic Essential Fatty Acid- Omega-6 (alpha-linoleic

acid)acid)

omega end alpha

end 1st double bond is located on the 6th

carbon from the omega end

H H H H H H H H H H H H H O

H-C--C--C--C-- C--C =C--C--C=C--C--C--C--C--C--C--C--C-OH


Omega-6 Fatty AcidOmega-6 Fatty Acid

Found in vegetable oilsFound in vegetable oils Only need ~ 1 tablespoon a dayOnly need ~ 1 tablespoon a day Increase blood clotIncrease blood clot Increase inflammatory responsesIncrease inflammatory responses

Signs and Symptoms of Essential Fatty Acids Signs and Symptoms of Essential Fatty Acids DeficiencyDeficiency

flaky, itchy skinflaky, itchy skin diarrheadiarrhea infectionsinfections retarded growth and wound healingretarded growth and wound healing anemiaanemia

Heart DiseaseHeart Disease

Symptoms take years to developSymptoms take years to develop Plaque build-up can begin in childhoodPlaque build-up can begin in childhood Myocardial infarction (heart attack)Myocardial infarction (heart attack) StrokeStroke

Risk Factors for Heart DiseaseRisk Factors for Heart Disease

Age, Family History, SexAge, Family History, Sex Smoking, StressSmoking, Stress High blood pressureHigh blood pressure High blood cholesterol (hyperlipidemia)High blood cholesterol (hyperlipidemia)

• >200 mg/dl of total cholesterol>200 mg/dl of total cholesterol• HDL < 35 mg/dlHDL < 35 mg/dl• Cholesterol/HDL Ratio >4.5 Female, >5.0 MaleCholesterol/HDL Ratio >4.5 Female, >5.0 Male

DiabetesDiabetes Lack of regular exercise and obesityLack of regular exercise and obesity

The National Cholesterol The National Cholesterol Education ProgramEducation Program

Reduce fat intake to 7% of total energy intake Reduce fat intake to 7% of total energy intake from saturated fat if elevated LDL does not from saturated fat if elevated LDL does not respond to previous reductionrespond to previous reduction

PUFA up to 10% of CaloriesPUFA up to 10% of Calories MUFA 10-15% of Total CaloriesMUFA 10-15% of Total Calories Limit cholesterol to ~300 mg/dayLimit cholesterol to ~300 mg/day Reduce cholesterol to 200 mg/day if LDL remains Reduce cholesterol to 200 mg/day if LDL remains

highhigh Increase Soluble Fiber to 15-25 grams/dailyIncrease Soluble Fiber to 15-25 grams/daily

American Heart Association’s American Heart Association’s

RecommendationsRecommendations

No RDA for fatNo RDA for fat Eliminate smokingEliminate smoking << 30% of total energy intake (TEI) from all fats 30% of total energy intake (TEI) from all fats 8% -10% of TEI from saturated fat8% -10% of TEI from saturated fat << 10% of TEI from PUFA 10% of TEI from PUFA << 15% of TEI from MUFA 15% of TEI from MUFA << 300 mg cholesterol/day 300 mg cholesterol/day << 2400 mg sodium/day 2400 mg sodium/day Not recommended for children under 2 years oldNot recommended for children under 2 years old

Dr. Dean Ornish’s Program for Dr. Dean Ornish’s Program for Reversing Heart DiseaseReversing Heart Disease

10% of Total Fat Calories10% of Total Fat Calories Almost no Saturated FatAlmost no Saturated Fat Half of Fat Intake Each MUFA and PUFAHalf of Fat Intake Each MUFA and PUFA 5mg/day of Cholesterol5mg/day of Cholesterol 70-75% Carbohydrate70-75% Carbohydrate 10-15% Protein10-15% Protein

Dr. Nathaniel Pritikin’s ProgramDr. Nathaniel Pritikin’s Program

10% of Total Fat Calories10% of Total Fat Calories Almost no Saturated FatAlmost no Saturated Fat Low MUFA and PUFALow MUFA and PUFA <100mg/day of Cholesterol<100mg/day of Cholesterol 75-85% Carbohydrate75-85% Carbohydrate 10-15% Protein10-15% Protein >35 grams/daily Fiber>35 grams/daily Fiber <1600 mg/daily Sodium<1600 mg/daily Sodium

The Mediterranean DietThe Mediterranean Diet

Abundant in plant foodsAbundant in plant foods Olive oil and nuts are the most abundant Olive oil and nuts are the most abundant

sources of fatsources of fat Saturated fat <7% of total caloriesSaturated fat <7% of total calories Wine consumed in low to moderate Wine consumed in low to moderate

amountsamounts Physical activity encouragedPhysical activity encouraged Heart disease rates are lowHeart disease rates are low

Review of Lifestyle Habits to Review of Lifestyle Habits to Reduce Risk of Heart DiseaseReduce Risk of Heart Disease

Fat mayFat may Heart Disease Heart Disease Saturated Fat may Saturated Fat may Heart Disease Heart Disease Hydrogenated Fats may Hydrogenated Fats may Heart Disease Heart Disease Phytochemicals may Heart Disease Phytochemicals may Heart Disease Omega 3’s and MUFA may Heart DiseaseOmega 3’s and MUFA may Heart Disease Fiber IntakeFiber Intake Physical ActivityPhysical Activity

Avoid a Heart AttackAvoid a Heart Attack

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Lipids: Fats and Oils All Food Fats Were Not Created Equal!