PRESENTATIONS

9, 11, 16, 18, 23 MARCH

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Carbohydrate/lipid/protein/alcohol

4/9/4/7 kcal/gram17/37/17/29 kJ/gramNote alcohol = ethanol

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Last time we talked aboutdietary carbohydrate in sports

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Lecture 726 Jan. 2015LIPIDS

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OUTLINE OF LECTURE 7

1) LIPIDS DEFINED

2) STRUCTURES OF LIPIDS

3) LIPIDS IN FOODS

4) FUNCTIONS OF FATS IN FOODS

5) LIPID IDATME

6) FUNCTIONS OF LIPIDS

ESSENTIAL OR NOT? HEALTHY AND UNHEALTHY

METABOLISM

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1)LIPIDS defined

FAMILY OF COMPOUNDS THAT INCLUDES TRIGLYCERIDES (TG), PHOSPHOLIPIDS (PL) AND STEROLS

OTHER DEFINITIONWATER INSOLUBLE ORGANICCOMPOUNDS MADE UP OF C, H, AND O LIKE CARBOHYDRATES BUT LESS OAND THEREFORE 9 VS 4 KCAL/GM

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2)STRUCTURES OF LIPIDS

a) Triglycerides-fatty acids-structure, classification, in foods and function

StructureClassification

Organic acid

Saturated 14:0 Monounsaturated 18:1 Polyunsaturated 18:2 n-6 18:3 n-3

18:3 n-6 (gamma-linolenic) 18:3 n-3 (alpha-linolenic)

Glycerol Triglycerides

Mixed triglycerides

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REPLACE WITH FIG 5-2 ACETIC ACID

Fig. 5-1, p. 140

p. 134

p. 134

p. 135

p. 135

p. 135

p. 135

16

17

18

Fig. 5-4, p. 137

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TRIGLYCERIDES CONTINUED

TRIGLYCERIDES IN FOODProcessed fat-fat manipulated mechanically or

chemically

Hydrogenation-

-trans-fatty acids

Fig. 5-7, p. 138

Fig. 5-8, p. 139

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FUNCTION OF FATTY ACIDS IN FOOD

ESSENTIAL- LINOLEIC AND LINOLENIC

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B) Phospholipids- structure, classification, in foods and function

Structure- 2 FATTY ACIDS (FA) and polar head group-generally but exceptions

Classification

Choline-containing phospholipidsEthanolamine-containing phospholipidsPhosphatidylserinePhospatidylinositolSphingomyelin

Fig. 5-9, p. 140

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PHOSPHOLIPIDS CONTINUED

Foods- found naturally

FunctionMembranesLipoproteinsCell signalling

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C) Sterols- structure, classification, in foods and function

Structure- Ring structure

Classification-Sterols

Fig. 5-11, p. 141

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STEROLS CONTINUED

Foods- found naturally-cholesterol vs phytosterol

FunctionMembranes

LipoproteinsBile acidsHormonesVitamin D

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3)Lipids in foods

All lipid classifications we have discussed are in foods

Animals and plants have free fatty acids, triglycerides, and phospholipids

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LIPIDS IN FOODS CONTINUED

Animal have cholesterols (free and cholesterol esters)

Plants have phytosterols (free and esterified)

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LIPIDS IN FOODS CONTINUED

GRAINSBREADS/OATMEAL < 1 G FAT/SERVINGCROISSANT 10 G FAT/MEDIUM

VERY LITTLE FAT

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LIPIDS in FOODS CONTINUED

FRUITS AND VEGETABLES

BOILED POTATO –TRACE

HOMEMADE HASHBROWNS 11 G FAT/1/2 CUP

APPLE 0.4 G FAT/MEDIUM

AVOCADO 15 G FAT/MEDIUM

VERY LITTLE FAT OR NO FAT USUALLY

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LIPIDS IN THE FOODS CONTINUEDMILK, YOGURT AND CHEESE

WHOLE MILK 8 G/CUPREGULAR YOGURT 4 G/CUPREGULAR CHEESE 9 G/28G (1 OZ)

GENERALLY MORE FAT THAN GRAINS, FRUITS AND VEGETABLES BUT CAN ALSO GET FAT FREE, REDUCED FATAND WHOLE FAT VARIETIES

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LIPIDS IN FOODS CONTINUED

MEATS, POULTRY, FISH, PEAS, BEANS, LENTILS

GENERALLY MORE FAT THAN MILK, YOGURT AND CHEESE BUT CAN ALSO GET LEAN MEATS

CHUCK BLADE AND PORK 11 G/ 3 OZ (84 G)CHICKEN WITH SKIN 12 G/3 OZ (84 G)FISH – SALMON 5 G/3 OZ - COD 0.7 G/3 OZNUTS 14-21 G/3 OZ

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LIPIDS IN FOODS CONTINUED

MODIFIED FOODS

CARBOHYDRATE REPLACERS (PECTIN)

PROTEIN REPLACERS (EG DERIVED FROM A CORN PROTEIN)

FAT REPLACERS (EG OLESTRA)

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LIPIDS IN FUNCTIONAL FOODS MARGARINES- BENECOL

-BECEL-PRO-ACTIV -CORN OIL

-FLAX OIL -CANOLA OIL

CHICKEN FEED- OMEGA 3 AND OMEGA 6 FATTY ACIDS

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LIPIDS IN FUNCTIONAL FOODSCONTINUED

FISH CANOLA/FLAX

SEA BUCKTHORN OIL- MIX OF OMEGA 3 AND OMEGA 6 FATTY ACIDS

Fig. 5-6, p. 138

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4)FUNCTIONS OF FATS IN FOODS

•ABSORBING FLAVOURS AND AROMAS OF INGREDIENTS

•PROVIDING FLAVOUR OF ITS OWN

•CREAMY AND SMOOTH MOUTH TASTE

•TENDERIZING AND ADDING MOISTURE

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5) LIPIDS IDATME

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INGESTION OF LIPIDS

MOUTH-CHEWING

TUBE

INTRAVENOUS

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DIGESTION OF LIPIDS

goal of fat digestion

fats start out separated from enzymes in gi (gastrointestinal tract)-why?

mouth digestion of fat-sublingual lipase-minor in adults-triglycerides

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DIGESTION OF LIPIDS

Small intestine

-bile

-pancreatic and intestinal lipases – triglycerides-phospholipases -sterols not digested

Large intestine

- no digestion of lipids

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ABSORPTION OF LIPIDSsmall molecules

short chain fatty acidsmedium chain fatty acidsglyceroldirect to blood

larger molecules monoglycerideslong chain fatty acidsmicelles formed in intestinemicelles into intestinal wall cellschylomicrons formed and released into lymph

file:///D:/Media/Animations/chapter5/Absorption_of_Fat/0517.html

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TRANSPORT OF LIPIDS lipoproteins- chylomicrons (CM)

(POST-PRANDIAL ONLY) - very low density lipoprotein (VLDL) - low density lipoprotein (LDL)

- high density lipoprotein (HDL) - ALBUMIN

density change due to 2 factors

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LIPOPROTEIN METABOLISM

Chylomicrons- made in small intestine – acted on by lipoprotein lipase in blood to giveremnant particle which is taken up liverVLDL (very low density lipoprotein) made VIA LIVER

VLDL acted on by lipoprotein lipase in blood to give remnant particle (intermediate density lipoprotein or IDL) which is taken up by liver- liver puts out low density lipoprotein (LDL)

HDL ( high density lipoprotein) and albumin made by liver

Fig. 5-4, p. 137

Fig. 5-4, p. 137

Fig. 5-4, p. 137

FATTY ACIDS METABOLISED VIA KREB’S CYCLE TO GIVE LOTS OF ATP

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LIPID EXCRETION

-faeces-e.g. bile and undigested/unabsorbed lipid

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6) FUNCTIONS OF LIPIDS- ESSENTIAL OR NOT?- HEALTHY AND UNHEALTHY METABOLISM

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LIPIDS ESSENTIAL OR NOT ?

YES-WHY ?HEALTHY ROLES

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LIPIDS- ESSENTIAL OR NOT? YES - HEALTHY ROLES

1)INSULATION- HEALTHY ROLES

Protective layer in body to helpkeep heat losses down

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LIPIDS- ESSENTIAL OR NOT? YES

HEALTHY ROLES

2)SUPPORT AND PROTECTION FOR INTERNAL ORGANS AND BONES

Fat acts as support and cushioning for organs and cushioning for bones

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LIPIDS- ESSENTIAL OR NOT? YES

- HEALTHY ROLES

3)ABSORPTION OF FAT SOLUBLE VITAMINSFat soluble vitamins cannot be absorbed without fat in the diet

Why?

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LIPIDS- ESSENTIAL OR NOT? YES

- HEALTHY ROLES4)CELL MEMBRANES

Cholesterol and phospholipids are important in maintaining the structure and hence function of cell membranes

What is a cell membrane?

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LIPIDS- ESSENTIAL OR NOT? YES

- HEALTHY ROLES

5) GIVES STRUCTURE TO MOLECULESFatty acids give rise to triglycerides and phospholipids and cholesterol fatty acid complexes

Structure of lipids in part dictates their function

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LIPIDS- ESSENTIAL OR NOT? YES

- HEALTHY ROLES

6)METABOLICALLY

FAT STORED AS FAT- VERY EFFICIENTMAKING FAT FROM CARBOHYDRATE AND PROTEIN IS NOT VERY EFFICIENT

ENERGY SOURCE-CAN STORE HUGE QUANITIES OF FAT

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LIPIDS- ESSENTIAL OR NOT? YES

- HEALTHY ROLES

7) IMPACT ON NUTRIENT ABSORPTION-GUT MOTILITY IS SLOWED-SLOWER RATE OF DIGESTION

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FATS UNHEALTHY ROLES

FAD DIETS

NO FAT OR LESS THAN 10 % OF CALORIES AS LIPID IN DIET

WITH ALL OR MOSTLY ALL OF ENERGY DIFFERENCE MADE UP WITH CARBOHYDRATE

AVOID !!!

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UNHEALTHY ROLES

FAT TO FAT- OBESITY

-OBESITY- TOUGH ON JOINTS, -MAY CONTRIBUTE TO ARTHRITIS

-ELEVATES BLOOD PRESSURE- WHICH MAY GIVE ATHEROSCLEROSIS AND HEART ATTACKS AND STROKE

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UNHEALTHY ROLES OBESITY CONTINUED

-ELEVATES FREE FATTY ACIDS IN THE BLOOD WHICH MAY GIVE INSULIN RESISTANCE

-IF EXCESS FAT IN THE DIET THIS MAY CROWD OUT OTHER NUTRIENT CLASSES

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SUMMARY OF LECTURE 7

1) LIPIDS DEFINED

2) STRUCTURES OF LIPIDS

3) LIPIDS IN FOODS

4) FUNCTIONS OF FATS IN FOODS

5) LIPID IDATME

6) FUNCTIONS OF LIPIDS

ESSENTIAL OR NOT? HEALTHY AND UNHEALTHY

METABOLISM

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NEXT TIME

DIETARY LIPIDS IN SPORTS