triglycerides by abhishek jaguessar

8/4/2019 Triglycerides by Abhishek Jaguessar

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TRIGLYCERIDES

BY

ABHISHEK JAGUESSAR


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The Lipids: Triglycerides,Phospholipids and Sterols


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Lipids Objectives

1. Understand the chemical composition and differencesbetween fats

2. Explain the structural and functional processes of

triglycerides, phospholipids, and sterols 3. Describe the process of fat digestion and absorption

4. Discuss the different types of lipoproteins in the body

5. Clarify the recommended intakes of fat and essential fatty

acid requirements to meet daily nutritive needs 6. Describe the health-risk factors with over consumption of

lipids in the diet


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Fatty Acids

The Length of the Carbon Chain long-chain, medium-chain, short-chain

The Degree of Unsaturation saturated, unsaturated, monounsaturated,

polyunsaturated

The Location of Double Bonds omega-3 fatty acid, omega-6 fatty acid


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The Length of the Carbon Chain

Short-chain Fatty Acid

(less than 6 carbons)

Medium-chain Fatty Acid

(6-10 carbons)

Long-chain Fatty Acid

(12 or more carbons)


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Fatty Acids are Key Building Blocks

Saturated Fatty Acid

All single bonds between carbons


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Monounsaturated Fatty Acid

(MUFA)

One carbon-carbon double bond


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Polyunsaturated Fatty Acid

(PUFA)

More than one carbon-carbon double bond


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Location of Double Bonds

PUFA are identified by position of the

double bond nearest the methyl end (CH3)

of the carbon chain; this is described as a

omega number;

If PUFA has first double bond 3 carbons

away from the methyl end=omega 3 FA

6 carbons from methyl end=omega 6 FA


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Degree of Unsaturation

Firmness saturated vs. unsaturated

Stability oxidation, antioxidants

Hydrogenation advantages, disadvantages

Trans-Fatty Acids from hydrogenation


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HydrogenationHydrogenation


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Cis-fatty acid: Hs on same side of the double bond; fold intoa U-like formation; naturally occurring;

Trans-fatty acid: Hs on opposite side of double bond; more

linear; occur in partially hydrogenated foods;


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1. Shortening

2. Cube margarine:vegetable oil blend (partially

hydrogenated soybean oil and liquid

soybean oil), water, whey, etc

1 Tbsp: 9 g fat; 2 g SFA; 2 g PUFA;

2.5 g MUFA;

3. Light Tub Margarine:water, liquid and partially hydro-

genated soybean oil, maltodextrin,etc.

1 Tbsp: 6 g fat; 1 g SFA;


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But, is all Trans FatBad?

CLA

Conjugated Linoleic Acid


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Essential Fatty Acids (EFA)

Omega-3:Eicosopentaenoic acid (EPA)

Docosahexaenoic acid (DHA)

Alpha-linolenic acid (ALA) flaxseed--most, canola (rapeseed), soybean, walnut,

wheat germ

body can make some EPA and DHA from ALA

Omega-6 corn, safflower, cottonseed, sesame, sunflower

Linoleic acid

FISH


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Omega-3

Omega-6


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Omega-3 Fatty Acids

Associated with: anti-inflammatory, antithrombotic, antiarrhythmic,

hypolipidemic, vasodilatory properties

Inflammatory conditions

Ulcerative colitis, Crohns

Cardiovascular disease

Type 2 diabetes * Mental functionRenal disease * Growth and

development


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Essential Fatty Acid Deficiency

Classical symptoms include: growth retardation, reproductive failure, skin

lesions, kidney and liver disorders, subtle

neurological and visual problems

People with chronic intestinal diseasesDepression--omega-3

?inadequate intake alters brain activity or

depression alters fatty acid metabolism?

Attention Deficit Hyperactivity Disorder lower levels of omega-3--more behavioral problems


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Eicosanoids: made from EFA--derivatives of 20-carbon fatty acids;

--affect cells where they are made;--have different effects in different cells

--cause muscles to contract and muscles to relax;

--help regulate blood pressure, blood clotformation, blood lipids, and immune response;

--participate in immune response to injury and

infection, producing fever, inflammation, and

pain;

--include:prostaglandins, thromboxanes,

leukotrienes


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Triglycerides

StructureGlycerol + 3 fatty acids

Functions Energy source

9 kcals per gramForm of stored energy in adipose

tissue

Insulation and protection

Carrier of fat-soluble vitamins

Sensory properties in food


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Triglycerides: lipids composed of three fatty acids

attached to a glycerol


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TriglyceridesFood sources

fats and oils

butter, margarine, meat, baked goods, snack foods,

salad dressings, dairy products, nuts, seeds

Sources of omega-3 fatty acids

Soybean, canola, walnut, flaxseed oils

Salmon, tuna, mackerel

Sources of omega-6 fatty acids

Vegetable oils


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Fatty Acids in Common Food FatsFatty Acids in Common Food Fats


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PhospholipidsStructure

Glycerol + 2 fatty acids + phosphate

group

FunctionsComponent of cell membranes

Lipid transport as part of lipoproteins

Emulsifiers

Phosphatidylcholine

Food sources Egg yolks, liver, soybeans, peanuts


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Cell membranes are phospholipid bilayers


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Sterols: Cholesterol

FunctionsComponent of cell membranes

Precursor to other substancesSterol hormones

Vitamin DBile acids

Synthesis

Made mainly in the liverFood sources

Found only in animal foods


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Lipid Digestion

In the Mouth hard fats begin to melt; lingual lipase

In the Stomach gastric lipase--SCFA

In the Small Intestine release of CCK; bile-emulsifier; fat drawn into

surrounding watery fluids; intestinal lipases;

remove each TG fatty acid; leave glycerol;Bile Routes

reabsorbed or trapped by dietary fiber


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Olestra


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OlestraSucrose + fatty acids

Indigestible provides zero kcals

Reduces absorption of fat-soluble

vitaminsSo many fatty acid chains are crowded

around the core, the digestive enzymes

cannot find a breaking point

Orlistat (Xenical)* binds to active site of GI lipase and blocks its

activity; thus, lipase cant break TG down to

component parts; TG remains undigested

and unabsorbed

triglycerides by abhishek jaguessar

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