Unit 5: The Lipids: Fats, Oils, Phospholipids and Sterols

What are Lipids?

organic compounds soluble in organic solvents, but not water

Functions of fat in body:

1. stores fat

2. secretes hormone for appetite

3. protects internal organs by absorbing shock

4. insulates body from extreme temps

5. part of cell membrane

6. can be converted to other compounds: hormones, bile, vit D

Functions of fat in foods":

1. provides essential nutrients like essentail fatty acids, fat soluble vit

2. provide E and raw material to make products

3. Provides tase, smell, and tender texture

4. stimulates appetite

5. Feel full

What is the DRI for fat

20-35% E

DRI for saturated fat

<10% E

lowering what kind of fats reduce blood cholesterol and heart disease risk?

saturate and trans fat

Which fat helps with blood clotting reduction

unsaturate fat

DRI of polyunsaturated fatty acids in linoleic acid and which omega is it

5-10% E (omega 6)

DRI of polyunsaturated fatty acids in linolenic acid and which omega is it

0.6-1.2% (omega-3)

What is the DRI for cholesterol

minimize intake depending on healthy diet

how many populationresponds to lowering dietary cholesterol intake?

1/3

which foods does it say about lowering dietary cholestroy intake that we should limit

lmit:

• eggs

• liver

  • shellfish

classes of lipids

1. triglycerides

2. phospholipids

3. sterols

what is the major form of lipid found in the body and in foods

tryglycerides

what is the tryglycerides made up of

made up of 3 fatty acids and a glycerol backbone.

where are fatty acids usually incorporated and where are they found in few?

• tryglycerides

  • in body or in foods

What is glycerol made up of

organic compound 3 carbons long

what and why affect the type of glycerides made

fats in the diet because dietary fats are incorporated into tryglcerides in the body

What are the fatty acids classified by

1. chain length

   1. degree of saturatation (double bonds)

what are the different chain lengths and how many

1. short: </ 10 C

2. medium 12-14 C

   1. Long: /> 16 C

Whats significant about short chain fatty acids

softer

melt more readily at rm temp

what is saturation

refers to the number of hydrogen atoms a fatty acid chain is holding.

what does it mean if the fatty acid is attached to more H atoms?

the more saturated the fatty acid is

What is unsaturation? what forms?

no H attached

• double bond forms

where do double bond usually occurs in the fatty acid?

fatty acids of plants and fish

What is saturated fatty acid? describ

no points of unsaturation

• solid at rm temp

  • animal fat (butter, lard), tropical oils (conconut and palm oil)

What is monounsaturated fatty acid (MUFA)

provide example

1 point of unsaturation

• vegetable oils (canola and olive oil)

what are polunstaturated fatty acid PUFA? describe state at rm temp? whre is it usually in

2 or more unsaturation

• liquid at rm temp

• vegetable and fish oil

What does the degree of saturation affects?

1. the temp at which fats melt

   1. the more unstaturated the fat, the more liquid it tends to be at rm temp

whats generally the most saturated and hardest fat?

animal fats

What is recommended by researchse to replace sat and trans fat with?

with mono and/or poly unsaturated fats

diff between sat fat and trans fat

Saturated fat can increase your ‘bad’ blood cholesterol level (LDL)

trans fat can increase your ‘bad’ blood cholesterol level (LDL) and decrease your ‘good’ blood cholesterol level (HDL), therefore may increase the risk for heart disease.

What is an example of unsat fat?

margarine

how margarine made? and what does it mean

Hydrogenation - H add to unsat fatty acids to make it more solid

How does hydrogenation work

H attatch to the unsaturated fatty acid or double bond, and makes the fatty acid saturated (no more double bond), overall making the fatty acid more solid at room temp and increases shelf life

why do we store cooking oil in tightly sealed containers?

because points of unsaturation is vulnerable to oxidation

• so when oxygen mixes with the fat, causing it to go rancid or taste “off

which fats can resist oxidation fats? what else are resistant to? and whats their shelf life like? what else is signifacnt?

hydrogenated fats as it has no points of unsat

• breakdown of high cooking temps

• longer shelf life

• higher smoking point and more suitable for frying

what heppsn to unsat fatty acid when H is added?

1. unsaturated fatty acids become more saturated and the oil hardens and becomes easier to spread, and lose their health benefits

What is the problem w hydrogenation?

• affects fatty acids in fats

• vitamins: decreases vitamin K in body

what does the DRI committee recommend ppl when it comes to trans fat?

consume it as little as possible because it risks heart health and arteries by raising bad levels of chol, and lower good levels of chol in body

• also produces inflammation

What happens when the change shape instead when unsaturated fatty acids are hydrogentatd and not become saturated?

• creates unusual shaped unsaturate FA that look like sat FA

what are trans fatty?

unusual shaped unsaturate FA that look like sat FA

What did health canada ban in 2018 

using partially hydrogenated oils in foods sold in Canada (both Canadian and imported foods), which has significantly reduced trans fat intake in Canada.

Whats a way to make soft non hydrogenated margarin? what does this process avoid? example of soft margarine?

Blending diff oils 

• avoid creating trans fatty acids is through a process of blending oils together

  • becel

What is soft non-hydrogenated marg like?

not solid at rm temp

fats are unsaturated

What are the clasffication of phospholipids?

• Glycerol backbone + 2 fatty acids + phosphorus containing molecule

• Water and fat soluble

• Can serve as emulsifier

• structure of cell membranres

Whats lecithin? how does it work in mayo? what special health abiltiy does it promote?

phospholipid found in egg yolk

• lecithin blends the vinegar with the oil and keeps it from separating

• doesnt promote any special health abilities

what makes phospholipid soluble in water

phosphorus molecule

claims about lecithin supplemetns? is it non essential or essential?

allegedly lowers blood chol

• its non essential ( body can make it)

What are sterols?

large molecules consisting of interconnecting rings of carbon atoms, with side chains of CHO

Whats an example of sterol? whats it imp in?

CHOlesterol

• in the structure of cell membranes, therefore is part of every cell and is necessary for optimal body functioning.

What is neccesary to make with chol?

1. Bile – important for fat digestion

2. Vitamin D

3. Sex hormones, e.g., estrogen, testosterone

   1. Stress hormones, e.g., epinephrine

Whats bad about cholesterol..? is it essential or not

forms the plaques that narrow the arteries in atherosclerosis

• not essential because body can make it

What is atherosclerosis

underlying cause of heart attacks and strokes

What happens to fat when we eat it in the mouth then stomach

small amounts of fat digestion occurs in the mouth (specifically milk fat).

• Once the fat enters our stomach, the fat separates from the watery chyme and floats on top of it. Because fat does not mix with the watery stomach contents, little fat digestion occurs in the stomach.

What happens to fat in the small int → bile

• as sson as fat enters in the small int, the gallbladder puts the stored bile in the int

• then bile emulsifies fat with watery digestive fluids, because one end attracts and holds fats, while the other end is attracted to and held by water

• bile also emulsifies it so fat digesting enzymes from pancrease can split into smaller partciles to be absorbed

What happens if a person removes their gall bladder?

lvier will stop producing bile

• bile will continously release into sm it in sm ammounts

• overall, only small amounts of fat is handled at a time

what happens after int contents are emulsified?

fat-splitting enzymes work on triglycerides to free the fatty acids from the glycerol backbone

what happens to the free fatty acids from the glycerol backbone?

glycerol and monoglycerides (glycerol molecule with 1 fatty acid) cling together in balls surrounded by bile.

• The bile helps to move the fats across the watery layer of mucus that coats the absorptive lining of the digestive tract.

What happens to small lipids at the lining of digestive tract

• small lipid particles enter directly into the capillary network and travel unassisted to the liver.

what happens to large lipid molecules at the linign of the digestive tract

• large lipid molecules are re-formed into triglycerides in the intestinal cells and are packaged together with proteins and phospholipids to form chylomicrons, which can safely travel in the watery blood

whats an example of lipid transport? what does it do

lipoproteins move lipids in blood and lymph

examples of lipoproteins?

1. chylomicrons

2. Very Low Density liporpotein

3. Low desnity lipoprotein

4. high desnity lipoprotein

What are chylomicrons

clusters formed when dietary lipids combine with carrier proteins in the cells of the intestinal tract. They transport dietary fat through the water body fluids to the liver and other tissues

What are Very low density lipoprotein (VLDL)

transport triglycerides and other lipids from the liver to various tissues in the body for use.

What are Low desnity lipoprotein?

transport cholesterol and other lipids from the liver to other tissues (muscle, fat). LDL are made from VLDL after they have donated most of their triglycerides to body cells.

what are high desnity liporptein?

are critical in the process of carrying cholesterol away from body cells to the liver for disposal

cmpare high desnity and low density liprotein

LDL

• larger, lighter and richer in cholesterol

• assocaited with risk for heart disease

HDL

• smaller, denser and packaged with more protein.

• associated with low risk for heart disase

What happens when body starts to rubn out of fuel from food?

turns to body stores

1. Fatty acids are used for energy by many organs: typical fuel mix at rest is 50/50 carbohydrate/lipid for liver and muscle

2. Any time fat is broken down for energy, carbohydrate must be available

3. Otherwise ketones develop (products of incomplete fat breakdown) and build up in blood and urine

Factors that increase the risk of heart disease?

1. High LDL cholesterol

2. Low HDL cholesterol

3. High blood pressure (hypertension)

4. Diabetes

5. Obesity

6. Physical inactivity

7. Smoking

8. high saturated and trans fats, and low in vegetables, fruits and whole grains diet

Chol is an important sterol in?

brain and nerve cells

how mcuh % of blood chol is synthesize in the body or de novo

75-80%

People vs chol tell me about it

limited amount of chol foods isnt a risk of increased levels of blood chol, since their body adapts to slow its own chol syntehsis when the diet provides more amounts

some ppl, have genetic tendencies towards high blood chol and need to limit foods that are high in sat and trans fat, and need meds to reduce the de novo (in the bodY) syntehsis of chol

food choles vs blood chol

Food cholesterol has less of an impact on blood cholesterol levels than most people think.

dietary chol vs sat and trans fat

Dietary cholesterol plays a lesser role than saturated and trans fat in cardiovascular disease

how many % exhibits lilittle increase in blood cholesterol with high cholesterol diet

60%

examples of dietary chol foods? 

eggs, meats, cheese, animal derived foods)

What is atherosclerosis

• Most common form of heart disease

• Characterized by plaque development along artery walls

• Starts with accumulation of soft fatty streaks, especially at points where the arteries branch.

• Soft fatty streaks gradually enlarge and harden to form plaque

  • Damage the artery walls by narrowing the passage through them and making them inelastic.

What are plaques

Mounds of lipid materials mixed with smooth muscle cells and calcium.

what are the complex inflammarotry response to tissue damage in atheroscelrosis

• White blood cells (macrophages) are sent to the site of damage

• LDL particles become trapped in blood vessel walls

• Free radicals oxidize the LDL

• Macrophages engulf oxidized LDL and become foam cells (filled with lipid) – these foam cells become a source of oxidation

• Muscle cells in artery walls proliferate to try to heal damage

• Muscle cells combine with foam cells

  • Fibrous plaques form (scar tissue)

What are ways to increase high density lipoproteins?

maintain a healthy body weight
- engage in regular physical activity
- quit smoking

What are ways to lower low density liporptoeins

maintain a healthy body weight
- increase intake of soluble fibre
- reduce intake of saturated and trans fat