Download 2107lecture 7

PRESENTATIONS
15, 20, 22 MARCH
Carbohydrate/lipid/protein/alcohol
4/9/4/7 kcal/gram
17/37/17/29 kJ/gram
Note alcohol = ethanol
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Last time we talked about
dietary carbohydrate in sports
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Lecture 7
25 Jan. 2017
LIPIDS
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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 DEFINITION
WATER INSOLUBLE ORGANIC
COMPOUNDS MADE UP OF
C, H, AND O LIKE
CARBOHYDRATES BUT LESS O
AND THEREFORE 9 VS 4
KCAL/GM
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2)STRUCTURES OF LIPIDS
a)
Triglycerides-fatty acids-structure, classification,
in foods and function
Structure
Classification
Organic acid
Saturated
14:0
Monounsaturated 18:1
Polyunsaturated 18:2 n-6
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
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Fig. 5-1, p. 140
p. 134
p. 134
p. 135
p. 135
p. 135
p. 135
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Fig. 5-4, p. 137
TRIGLYCERIDES CONTINUED
TRIGLYCERIDES IN FOOD
Processed fat-fat manipulated mechanically or
chemically
Hydrogenation-
-trans-fatty acids
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Fig. 5-7, p. 138
Fig. 5-8, p. 139
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 phospholipids
Ethanolamine-containing phospholipids
Phosphatidylserine
Phospatidylinositol
Sphingomyelin
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Fig. 5-9, p. 140
PHOSPHOLIPIDS CONTINUED
Foods- found naturally
Function
Membranes
Lipoproteins
Cell signalling
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C) Sterols- structure, classification, in foods and
function
Structure-Ring structure
Classification-Sterols
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Fig. 5-11, p. 141
STEROLS CONTINUED
Foods- found naturally-cholesterol vs phytosterol
Function
Membranes
Lipoproteins
Bile acids
Hormones
Vitamin 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
GRAINS
BREADS/OATMEAL < 1 G FAT/SERVING
CROISSANT
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 CONTINUED
MILK, YOGURT AND CHEESE
WHOLE MILK
REGULAR YOGURT
REGULAR CHEESE
8 G/CUP
4 G/CUP
9 G/28G (1 OZ)
GENERALLY MORE FAT THAN GRAINS,
FRUITS AND VEGETABLES BUT CAN ALSO
GET FAT FREE, REDUCED FAT
AND 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
CHICKEN WITH SKIN
FISH – SALMON
- COD
NUTS
11 G/ 3 OZ (84 G)
12 G/3 OZ (84 G)
5 G/3 OZ
0.7 G/3 OZ
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 FOODS
CONTINUED
FISH
CANOLA/FLAX
SEA BUCKTHORN OIL- MIX OF
OMEGA 3 AND OMEGA 6 FATTY
ACIDS
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Fig. 5-6, p. 138
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 LIPIDS
small molecules
short chain fatty acids
medium chain fatty acids
glycerol
direct to blood
larger molecules
monoglycerides
long chain fatty acids
micelles formed in intestine
micelles into intestinal wall cells
chylomicrons 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 give
remnant particle which is taken up liver
VLDL (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
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Fig. 5-4, p. 137
Fig. 5-4, p. 137
FATTY ACIDS METABOLISED VIA
KREB’S CYCLE TO GIVE LOTS OF ATP
Fig. 5-4, p. 137
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 help
keep 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 VITAMINS
Fat soluble vitamins cannot be absorbed
without fat in the diet
Why?
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LIPIDS- ESSENTIAL OR NOT? YES
- HEALTHY ROLES
4)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 MOLECULES
Fatty 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 EFFICIENT
MAKING 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
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