Fundamentals of Nutrition Ch. 5 The Lipids: Fats, Oils, Phospholipids, Sterols

What percentage of the resting body’s energy does fat provide?

80-90%

Fat provides much of the energy used to fuel ________ work

muscular

True or false: fats are the body’s chief form stored energy.

true

In what situation does fat serve as an emergency fuel supply?

In times of severe illness and starvation

What does fat protect from shock?

internal organs

How does fat protect internal organs?

cushioning the organs with fat pads inside the body cavity

How does fat insulate?

the layer of fat underneath the skin insulates the internal tissues against cold temps.

True or false: fats form a minor material of cell membranes

false, fats form the major material of cell membranes

Lipids are converted to their compounds, such as:

compounds, such as hormones, bile, and vitamin D as needed

What do lipids affect in cellular signaling pathways?

cell functioning

What are some essential nutrients in lipids?

fatty acids, fat-soluble vitamins, and other needed compounds

True or False: foods low in fat provide a concentrated energy source

false, foods that are high in fat

how do fats contribute to sensory appeal?

fats contribute to aroma, flavor, and physical sensation in the mouth

True or False: fats do not stimulate the appetite

false, they do

Fats make fried food crisp and other foods tender

just a fact

True or False: Fats in foods contribute to feelings of fullness

true

What are the 3 classes of dietary fats/lipids?

triglycerides, sterols, phospholipids

What is another name for triglycerides (TG)?

triacylglycerol

What is the primary dietary lipid?

triglycerides

what are triglycerides composed of?

glycerol + 3 fatty acids

True or False: fatty acids do not vary length.

false, they do vary in length

What are the lengths of the different fatty acids?

long chain, medium chain, short chain

How do fatty acids vary in degree?

of saturation or carbons with hydrogen

How many carbons are in short-chain fatty acids?

<6

how many carbons are in medium chain fatty acids?

6-12

how many carbons are in long chain fatty acids?

>14

what are the degrees of saturation?

saturated and unsaturated

what are saturated fatty acids?

carbons are saturated with hydrogen

what are unsaturated fatty acids?

not all carbons saturated with hydrogen

What are the two types of unsaturated fats?

monounsaturated FA and polyunsaturated FA

what are monounsaturated FA?

one double bond between carbons

what are polyunsaturated FA?

2 or more double bonds between carbons

saturated fatty acids remain _______ at room temp, while unsaturated fatty acids are _____ at room temp

solid; liquid

unsaturated FA are further identified based on the __________ of the first double bond relative to the ______ carbon.

location; omega

What are the 2 omega carbons?

omega-3 PUFA

omega-6 PUFA

What are 2 essential fatty acids?

alpha-linolenic acid (ALA)

linoleic acid (LA)

What is alpha-linolenic acid?

an essential omega-3 PUFA

precursor to other omega- 3FA

what is a linoleic acid (LA)?

an essential omega- 6 PUFA

precursor to other omega- 6 FA

What are trans-fatty acids?

partially hydrogenated oils

How are trans FA produced?

by added hydrogen to liquid veggie oils

________ hydrogenation creates trans fats and ________ hydrogenation creates saturated fats

partial; full

When were trans fats banned in the US?

2015

Why are trans fats bad?

raise LDL (“bad cholesterol”) and lowers HDL (“good cholesterol”)

increase risk of heart disease

used primarily in processed foods

Which oil replaced trans fats since being banned?

palm oil

What are some food high in Saturated FA?

fatty beef cuts, fatty pork cuts, fatty lamb cuts, poultry with skin, cream (heavy cream, half and half), cheese, whole milk, yogurt, palm oil, coconut oil

Where does the digestion of triglycerides start?

in the mouth

What enzyme is found in the mouth during the digestion of TG?

lingual lipase

What does the digestion of TG continue after the mouth?

the stomach

What enzyme is found in the stomach during the digestion of TG?

gastric lipase

Where does digestion of TG primarily occur?

The small intestine

True or False: the steps of digesting TG are more important in adults; less relevant in infants?

False, more important in infants; less in adults

What is the goal of TG digestion?

to cleave 2 of the FA from the glycerol backbone

What are the primary components in the SI that aid in the digestion of lipids?

bile, pancreatic lipase

How many phases can digestion in the SI be considered?

2

What is the first phase of Digesting TG?

the gallbladder contracts and releases bile into the SI

Bile causes the emulsification of lipid

What is emulsification?

the process by which large lipid globules are broken down and stabilized in to smaller droplets

What is phase 2 of digesting TG?

pancreatic lipase is released into the SI from the pancreas

pancreatic lipase reacts with TG to split FA from their glycogen backbones

What are the end products of TG digestion in the SI?

free FA (not attached to the glycerol backbone)

glycerol

monoglycerides (one FA still attached to a glycerol)

The end products of TG digestion are absorbed into the _________

enterocytes

What are the chylomicrons?

lipoproteins formed when lipids from a meal cluster with carrier proteins in the cells of the intestinal lining?

What are lipoproteins?

clusters of lipids associated with protein, which serve as transport vehicle for lipids in blood and lymph

_________ and _________ FA travel in the bloodstream unassisted while chylomicrons are released from the enterocytes into the _________ _________

Glycerol; short chain; lymphatic system

The process of TG digestion, absorption, and transport into the _________ can take _________ _________ after consuming dietary lipids

blood stream; several hours

Most body cells can store only limited fat, but some cells are specialized for fat storage

fact

Where are TG primarily stored?

adipose tissue

What are the cells of adipose tissue called?

adipocytes

Where is most of the adipose tissue in the body located?

just below the surface of the skin

What kinds of fat is located just below the skin?

subcutaneous fat

The American Heart Associated recommends all adults at what age should have a blood lipid profile

20 or older

How often should adults get a blood lipid profile?

every 4-6 years

what is checked for in a blood lipid profile?

tr density lipoprotein cholesterol

low density lipoprotein cholesterol

total cholesterol

blood triglycerides

What are the major lipoproteins?

chylomicrons

very-low density lipoproteins (VLDL)

low density lipoproteins (LDL)

high density lipoproteins (HDL)

What does VLDL do?

transport TG and other lipids made in the liver to the body cells for their use

What does LDL do?

transport cholesterol and other lipids to the tissues for their use

LDL are what is left after VDL have donated many of their _____ to body cells

TG

what does HDL do?

pick up cholesterol from body cells and carry it to the liver for disposal

What is dyslipidemia?

is a condition in which the blood stream contains abnormal levels of lipids

abnormal levels in dyslipidemia include:

high LDL-C

low HDL-C

high TG

High total cholesterol

What percent of adolescents have dyslipidemia in the US?

20%

What are the most common causes of dyslipidemia in teens and children?

obesity, unhealthy eating, and a sedentary lifestyle

When LDL- C is too high, it contributes to ______ ________ in tissues, particularly in the linings of _______, that can trigger ________ and lead to heart disease.

lipid buildup; arteries; inflammation

HDL-C opposes the effects of high LDL-C, and when HDL-C in the blood ______ _______ the recommended level, heart disease risks ______ in response

drops below; rise

What are 2 major risk factors for heart disease?

high blood LDL-C and low blood HDL-C

What factors have a negative impact on our blood lipid profile?

saturated fat and trans fat elevate LDL-C

excessive alcohol intake elevates bood TG

dietary cholesterol may increase LDL-C.

What can have a positive impact on our blood lipid profile?

exercise raise HDL-C and lowers TG

maintaining a healthy body weight lowers TG

consuming omega-3 PUFA containing foods lowers TG (fish or fish oil supplement)

replacing saturated and trans fat w/ PUFA and/or MUFA lowers LDL-C

high fiber foods lowers LDL-C

What are some healthy fats?

monounsaturated

polyunsaturated (especially omega-3 PUFA)

What are some unhealthy fats?

saturated, trans