PH BIO SCI 21 - 3A. LIPIDS

Triacylglycerols

Triacylglycerols

Energy-storage lipids

Glycogen

the most widespread energy-storage material within cells is the carbohydrate _________; present in small amounts in most cells.

Triacylglycerols

Known is the body’s energy storage materials; concentrated primarily in special cells (known as adipocytes) that are nearly filled with it.

Adipose tissue

These are found in various parts of the body; under the skin, abdominal cavity, mammary glands, and various organs

Triacylglycerols

- more efficient at storing energy than is glycogen because large quantities of them can be packed into a very small volume
- energy storage lipids, and the most abundant type of lipid present in the human body

Triesters

Triacylglycerols, in terms of functional groups present, are ______, meaning there are three ester groups present.

Glycerol

The alcohol involved in triacylglycerol formation is always ___________, a three-carbon alcohol with three hydroxyl groups.

Esterification

In the ____________ reaction producing a triacylglycerol; wherein a single molecule of glycerol reacts with three fatty acid molecules; each of the three hydroxyl groups are esterified.

Glycerol and three fatty acids with three ester linkages

A triacylglycerol contains ______________.

Triacylglycerol

A _________ is a lipid formed by esterification of three fatty acids to a glycerol molecule.

Acyl group

A portion of a carboxylic acid that remains after the -OH group is removed from the carboxyl carbon atom.

Triacylglycerols

___________ molecules contain three fatty acid residues(three acyl groups) attached to a glycerol residue.

Triglyceride

The older name for a triacylglycerol is ________.

Simple Triacylglycerol

__________ is a triester formed from the esterification of glycerol with three identical fatty acid molecules.

Mixed Triacylglycerol

If the reacting fatty acid molecules are not at all identical, then the result is a _________________.

Mixed Triacylglycerol

A ___________ is a triester formed from the esterification of glycerol with more than one kind of fatty acid molecule.

Fats and Oils

naturally occurring mixtures of triacylglycerol molecules in which there are many different kinds of triacylglycerol molecules present

Fat

triacylglycerol mixture that is a solid or a semi-solid at room temperature

Fat

obtained from animal sources

Oil

triacylglycerol mixture that is a liquid at room temperature

Fats

saturated fatty acids dominate; and a higher melting points due to “linearity”

Oils

mono and polyunsaturated fatty acids dominate; and a lower melting point due to “bends”

Pure Fats and Pure Oils are:

colorless, odorless, and tasteless.

naturally occuring substances present in the plant during processing

The taste, odor, and colors associated with plant oils are ________________________, considered desirable.

unsaturation

A higher degree of fatty acid _________ is associated with oils than with fats; except with coconut oil which is highly saturated.

Coconut oil

The exception of the generalization that oils are unsaturated, as this is very saturated due to lauric acid.

high dietary intakes of triacylglycerols (fats and oils) tend to have _____________

higher incidences of heart disease and certain types of cancers.

In the Mediterranean and Inuits, dietary triacylglycerol intake and risk factors for disease involve more than simply the total amount of triacylglycerols consumed, but also the ________.

kind of triacylglycerol consumed.

30%

Current dietary fat recommendations are that people limit their total fat intake to _________ of total calories.

15%

Percent of Monounsaturated Fats that should be in our diet

10%

Percent of Polyunsaturated Fats that should be in our diet

<10%

Percent of Saturated Fats that should be in our diet

Which fat is termed as “bad fat”?

Saturated Fats

Which fat is termed as “good fat"?

Monounsaturated Fats

Which fat is both “good fat” and “bad fat”?

Polyunsaturated Fats

Saturated fat can ________ heart disease risk.

increase

Monounsaturated Fat can __________ both heart disease and breast cancer risk

decrease

Polyunsaturated fat can _____________ heart disease risk

reduce

promote

Polyunsaturated fats can _____________ the risk of certain types of cancer

Dietary fats high in “good” monounsaturated fatty acids include

olive, avocado, and canola oils

Monounsaturated Fatty Acid

This fatty acid reduces stickiness of blood platelets and prevent the formation of blood clots and may also dissolve clots once they form

Tree nuts and peanuts

These are good sources of MUFAs

The _____________ is high in omega-3 fatty acids (from fish)

Inuit Diet

The _____________ is high in omega-6 fatty acids (from plant oils)

U.S. Diet

_______________, also called fatty fish because of the extra fat they have for insulation contains more omega-3 acids compared to leaner, warm-water fish

Cold-water fish

Albacore tuna, salmon, and mackarel

Examples of fatty fish (cold-water fish)

Wild salmon

primary source for omega-3 fish oil supplements

Fish do not make the omega-3 fatty acids, they obtain the fatty acids from the _______ they feed on.

algae

A fatty acid that is needed in the human body that must be obtained from dietary sources because it is not synthesized within the body, in adequate amounts, from other substances

Essential fatty acid

Linoleic acid

primary member of the omega-6 acid family

Linoleic acid (shorthand notation)

18:2

Linolenic acid

primary member of the omega-3 acid family

Linolenic acid (shorthand)

18:3

Importance of Essential Fatty Acids

- proper membrane structure
- starting materials for the production of several nutritionally important longer chain omega 3 and 6 acids.

What happens when linoleic and linolenic acids are missing from the diet?

The skin reddens, infections and dehydration, and liver abnormalities

___________ contains more essential fatty acids than cow’s milk

Human breast milk

Linoleic acid is the starting material for the biosynthesis of ________________.

Arachidonic acid

Arachidonic acid is the major starting material for _________________

eicosanoid substances

______ help regulate blood pressure, clotting, and several other important body functions

eicosanoid substances

The eicosanoids are considered as they act on cells close to their site of production and are rapidly degraded.

autacoids

These have both intercellular signaling, and intracellular signal cascades

Eicosanoids

Selective COX-2 Inhibitors

Celecoxib
Rofecoxib

Non-Selective COX 1&2 Inhibitors

Aspirin
Acetaminophen
Ibuprofen
Naproxen
Nabumetone
Diclofenac

Glucocorticoids (Corticosteroids)

Beclomethasone
Dexamethasone

Leukotriene Inhibitors

Montelukast
Zafirlukast
Zileuton

Linolenic acid is the starting material for the biosynthesis of these two omega-3 fatty acids

EPA (Eicosapentaenoic acid)
DHA (Docosahexaenoic acid)

What does EPA (20:5) mean

Eicosapentaenoic acid

What does DHA (22:6) mean

Docosahexaenoic acid

What are EPA and DHA important for?

-constitutes of the communication membranes of the brain, and are necessary for normal brain development
-active in the retina of the eye

DHA and EPA Omega 3’s on MOOD

increases neural phospholipids
involved in brain cell signaling for dopamine and serotonin

DHA and EPA Omega 3’s on HEART HEALTH

aids regulating of lipid metabolism
lowers triacylglycerides
lowers gene expression for heart disease

DHA and EPA Omega 3’s for COGNITION/BEHAVIOR

essential for neurological functioning
aids formation and maintenance of learning and memory
Increases brain plasticity

DHA and EPA Omega 3’s for INFLAMMATION

precursor for anti-inflammatory metabolites
lowers gene expression for inflammation

Biochemically Important Omega-3 Acids consist of:

Linolenic acid
Eicosapentaenoic acid
Docosahexaenoic acid

Biochemically Important Omega-6 Acids consist of:

Linoleic acid
Arachidonic acid

Artificial fats

Food scientists developed this due to a demand for low-fat, low-calorie foods.

Two types of fat substitutes

Simplesse and Olestra

Simplesse

calorie-reduced fat substitutes

Olestra

calorie-free substitutes

Simplesse

This is the best-known calorie-reduced fat substitute that received FDA marketing approval in 1990.

Microparticulation

Simplesse is made from the protein of fresh egg whites and milk by a procedure called this.

Simplesse is used only to replace fats in foods such as salads, dressings, cheeses, sour creams, and other dairy products.

formulated foods

Simplesse is not used for?

frying and baking, as it turns rubbery or gel-like when heated

Olestra

best known calorie-free fat substitute, received FDA marketing approval in 1996.

Olestra

produced by heating cottonseed and/or soybean oil with sucrose in the presence of methyl alcohol

Uses of Olestra

dietary fats and can substitute for fats and oils in foods such as shortenings, oils, margarines, snacks, ice creams, and other desserts, and has the same cooking properties as fats and oils

Olestra

interferes with the absorption of both dietary and body-produced cholesterol, thus it may lower total cholesterol levels

Fat Soluble Vitamins

Vitamins A,D,E, and K.

Olestra

interferes with the absorption of fat-soluble vitamins A, D, E, and K; and can cause gastrointestinal irritation and/or diarrhea

Fat-free

meaning less than 0.5 g of fat per servings

Low-fat

meaning 3g or less fat per 50g serving

Reduced fat or less fat

at least 25% less fat per serving than the “regular” food

Calorie-free

means less than 0.5 kilocalories per serving