Chapter 5: Lipids

How does cholesterol affect digestion of fats in the small intestine

As a component of bile, it emulsifies fats

Why are the chemical structures of trans and saturated fatty acids similar?

Both have a straight shape

What do triglycerides and phospholipids have in common?

Built on a backbone of glycerol

Essential fatty acids _____ be synthesized in the body

Cannot

Cis fatty acid

Causes the carbon chain to bend

What deficiency would you suspect is a person has flaky and itchy skin, diarrhea, and poor wound healing with infections?

Essential fatty acids

Choose the fish species that are highest in mercury

-Swordfish -Shark -King mackerel

LDL function

Carries cholesterol made by the liver and from other sources to cells

Chylomicron function

Carries dietary fat from the small intestine to cells

VLDL function

Carries lipids made and taken up by the liver to cells

Fatty acid structure

Chain of carbons flanked by hydrogens

Myocardial infarction

Blood flow surrounding the heart is blocked resulting in damage to the heart muscle

Cerebrovascular accident

Blood flow to parts of the brain is blocked resulting in the death of brain cells

Immediately after a meal, newly digested and absorbed dietary fats appear in the lympt and then the blood as part of _____. a) Low-density Lipoproteins b) High-density Lipoproteins c) Chylomicrons d) Cholesterol

Chylomicrons

HDL function

Contributes to cholesterol removal from cells and excretion from the body

_____ is a phospholipid and a major component of cell membranes

Lecithin

Phospholipid definition

Lecithin is an example of this lipid

What enzyme breaks down triglycerides into free fatty acids and glycerol in the bloodstream?

Lipoprotein lipase

Triglyceride chemical structure

Three fatty acids attached to a glycerol backbone

Choose a lipid that can be synthesized by the body?

cholesterol

A compound containing a multi-ring structure and a hydroxyl group is a

sterol

Which of the following are types of lipoproteins?

-LDL -HDL -VLDL

Which of the following food ingredients indicate the presence of fat in a food product?

-Lard -Cream -Partially hydrogenated vegetable oil -Egg yolks -Shortening

What are some examples of foods that are considered high in fat?

-Margarine -Salad oils -Butter -Mayonnaise

Enzymes that digest fat are secreted by the ______.

-Stomach cells -Pancreas -Salivary glands

What happens to a food product when it becomes hydrogenated?

-The molecular shape of the fats in the food resembles saturated fats -Trans fatty acid content is increased

True statements about avocados

-They are rich in monounsaturated fatty acids -They can be substituted 1:1 for butter in recipes for baked goods

One bowl of chicken tortilla soup has 5 grams of fat, which means that the food provides _____ kilocalories from fat

45

Having an HDL level above _____ mg/dl and a total cholesterol to HDL below _____ is especially protective of cardiovascular disease

60; 3.5:1

LDL primary component

Cholesterol

Omega-3 effect on blood-clotting and inflammation

Decrease blood-clotting and inflammation

Polyunsaturated fatty acids effect

Decreases blood levels of cholesterol

People who have impaired fat absorption (e.g., cystic fibrosis patients) may be at risk for

Deficiency of fat-soluble vitamins

Three fatty acids combine with glycerol to form

a triglyceride

Lipoproteins are important for: a) Transport of fats in the blood and lympathatic system b) Synthesis of triglycerides c) Synthesis of adipose tissue d) Enzyme production

a) Transport of fats in the blood and lymphathic system

Primarily, fatty acids are transported through the bloodstream

as part of lipoproteins

Omega-6 Classification

Essential fatty acid; Linoleic acid

Cholesterol is an essential nutrient

False

Phospholipids do not contain fatty acids within their molecular structure

False

Long-chain saturated fat food sources

Fat in beef, pork, lamb, lard

Lipid-loaded white blood cells that have surrounded large amounts of a fatty substance, usually cholesterol, on the blood vessel walls are called

Foam cells

Phospholipid structure

Glycerol backbone with fatty acids and at least one phosphorus-containing group

Triglyceride structure

Glycerol backbone with three fatty acids

Omega-6 effect on blood-clotting and inflammation

Increase blood-clotting and inflammation

Saturated fatty acids effect

Increases blood levels of cholesterol

What does it mean when a fatty acid is considered essential?

It must be supplied by the diet in order to maintain health.

Phospholipid

Lecithin

The enzyme _____ plays an important role in fat digestion

Lipase

Due to their high energy density (9 kcal per gram) _____ are the ideal form of energy storage for the body

Lipids

_____-density lipoprotein is considered the "bad" cholesterol

Low

Trans fat food sources

Margarine, shortening

Triglyceride definition

Most fat in the body and in food

Omega-9 Classification

Nonessential fatty acid

Fatty fish provide eicosapentaenoic acid (EPA) and docosahexaenoid acid (DHA), which are two ______ that important for brain and heart health

Omega-3 fatty acids

The majority of fatty acids in the body and in foods are _____-chain fatty acids

long

The majority of fat digestion is accomplished by

Pancreatic lipase

In 2015, the FDA determined that _____ are no longer "generally recognized as safe" for use in human food products

Partially hydrogenated oils

What is one of the most important functions of the phospholipid molecule?

Phospholipids help form cell membranes

_____ is a cholesterol-rich substance deposited in the blood vessels

Plaque

Which type of treatment is typically used when only one artery is blocked?

Precutaneous transluminal coronary angioplasty (PTCA)

Choose a function of fat tissue

Protect organs from injury

Chylomicron remnant

Removed from circulation by the liver and recycled to make other lipoproteins and bile acids

______ fatty acids consist entirely of carbon-carbon single bonds

Saturated

Which class of lipids may serve as precursors for hormone synthesis?

Sterols

Which of the following is the body's most efficient form of stored energy?

Triglycerides

An omega-3 fatty acid is

Unsaturated

Essential fatty acids

must be obtained from the diet

According to the American Health Association, to reduce risk for cardiovascular disease, saturated fats should contribute

no more than 5% to 6% of total kilocalories

Fatty acid

omega-6, omega-3

Monounsaturated fatty acid structure

one carbon-carbon double bond

Most foods containing saturated fatty acids are _____ at room temperature

solid

When fat is removed from a food, most manufacturers add _____ in its place

sugar

Polyunsaturated fatty acid

two or more carbon-carbon double bonds

What are some health benefits associated with consuming a diet high in omega-3 fatty acids?

-Reduced inflammation -Decreased blood triglyceride levels -Reduced risk of heart disease

How are long chain fatty acids absorbed?

-Reformed into triglycerides -Enter circulation via the lymphatic system

What is added to reduced-fat foods to compensate for the loss of taste and texture when fat is removed?

-Salt -Sugar

People who use mineral oil as a laxative at mealtimes risk deficiencies of

-Vitamin E -Vitamin D

Which of the following are functions of phospholipids in the body?

-Formation of cell membranes -Absorption and transport of nutrients -Digestion of fats

What are some examples of foods that may contain partially hydrogenates (trans) fats?

-French fries -Shortening -Potato chips -Stick margarine

What are the structural components of a triglyceride?

-Glycerol backbone -Three attached fatty acids

The cholesterol manufactured by the body is used to make

-Hormones -Bile acids

How many Kilocalories are in one gram of fat?

9

Free fatty acids

Absorbed by cells within the vicinity and reform into triglyceride for storage or use

In foods, what are the major sources of omega-3 and omega-6 fatty acids, respectively?

Alpha-linolenic; lineoleic

What two chemical groups are found at the end of either side of the fatty-acid carbon chain?

An acid group (COOH) and a methyl group (CH3)

What is the structure and function of glycerol molecules?

An alcohol containing three carbons; it is the backbone of a triglyceride molecule

_____ act(s) to emulsify fats in the small intestine, suspending them in digestive juices to enhance the action of digestive enzymes

Bile acids

The main reason for hydrogenating fats is to:

Change a liquid fat to a solid fat

Cholesterol definition

Characterized with a multi-ring structure

Enzymes released from the pancreas break _____ down to free cholesterol and fatty acids

Cholesterol

Plant oils are always _____-free

Cholesterol

Sterol

Cholesterol

Glycerol

Circulates back to the liver

Sterol chemical structure

Multi-ring structure with a hydroxyl group

A saturated fatty acids contains:

No double bonds

Some plants contain natural cholesterol-lowering compounds called

Plant sterols

Omega-3 fatty acids effect

Reduces inflammation responses, blood clotting, and triglycerides

A(n) _____ is made of three fatty acids attached to glycerol.

Triglyceride

A(n) _____ is made up of a glycerol backbone attached to 3 fatty acids.

Triglyceride

Lipids in foods and in the body are mostly in the form of _____

Triglycerides

Megadoses of nicotinic acid, a form of a B vitamin, can lower

Triglycerides

About half of the energy our body uses at rest and during low-intensity exercise (or light activity) comes from fatty acids.

True

Saturated fatty acid structure

no carbon-carbon double bond

What are some of the positive attributes of fat in the diet?

-Fat imparts a creamy texture to foods -Many flavors are fat soluble, so fat enhances the flavor of foods

Counting from the methyl end of an omega-3 fatty acid, the first double bond occurs between the

Third and fourth carbons

Heart disease is the _____ leading cause of death among North American adults

#1

Which statements are true about a diglyceride?

-It consists of two fatty acids bonded to glycerol backbone -it is the breakdown product of a triglyceride

Choose the two approaches to treating heart disease that have been shown to cause a reversal of atherosclerosis in the body.

-Aggressive LDL-lowering medications -Vegan diet and lifestyle changes that are part of the Dr. Dean Ornish program

What are the two most common synthetic antioxidant additives in foods?

-BHA -BHT

Current cholesterol-lowering medications act to

-Bind to cholesterol in the GI tract -Reduce cholesterol synthesis in the liver

What are some ways to limit trans fat intake at home?

-Broil, pan-fry, or grill meats instead of deep-fat frying with shortening -Use vegetable oils or softer tub margarines instead of stick margarine or shortening -Use reduced-fat or fat-free milk instead of non-dairy creamers

What are some components of plaque?

-Calcium -Cholesterol -White blood cells

What are some examples of food sources that contain cholesterol?

-Chicken -Ice cream -Eggs

Which of the following substances are types of lipids?

-Cholesterol -Triglycerides -Saturated fatty acids

Which of the following are functions of HDL cholesterol in the bloodstream?

-Donates cholesterol to other lipoprotein for transport back to the liver for excretion -Picks up cholesterol from dying cells and other sources

What two food types contribute the most to raising the level of cholesterol in your blood?

-Eating trans fat -Eating saturated fat

What are the products of fat digestion in the small intestine?

-Fatty acids -Monoglycerides

Arrange the following foods from lowest percentage of kcal from fat to the highest percentage of kcal from fat

1) Bread 2) Whole milk 3) Cheddar cheese 4) Canola oil

List the steps of the development of atherosclerosis in the arteries starting with arterial damage and ending with a heart attack

1) Damage occurs in blood vessel lining 2) Plaque is deposited at the sit of initial damage 3) As plaque accumulates, arteries harden, narrow, and lose elasticity 4) Clot or spasm in a plaque-clogged artery leads to a heart attack

Place the steps of dietary fat absorption in the order they occur

1) Glycerol, monoglycerides, and fatty acids are absorbed from the lumen of the small intestine into the small intestinal cells. 2) Triglycerides are reassembled within the cells lining the small intestine. 3) Triglycerides are packaged into chylomicrons. 4) Chylomicrons enter the lymphatic system.

Long-chain fatty acids contain ____ or more carbon atoms

12

A healthy blood pressure is less than _____ mm Hg for the systolic pressure and less than _____ mm Hg for diastolic pressure.

120; 80

The Acceptable Macronutrient Distribution Range set by the Food and Nutrition Board for lipids is _____% to ______% of kilocalories.

20; 35

Triglyceride

3 fatty acids and 2 glycerol molecule

Low fat definition

3g of fat or less per serving (or, if the serving size is small, per 50 grams of food)

How do you convert a liquid oil to a solid fat at room temperature?

Add hydrogens to the liquid fat (hydrogenation)

Trans fatty acid

Allows the carbon chain to remain straighter

Reduced or less fat definition

At least 25% less fat per serving in comparison to the full-fat version of the food product

Chylomicron primary component

Triglyceride

A major function of phospholipids (e.g., lecithin) in foods is to act as a(n)

emulsifier

Compared to foods made with unprocessed plant oils, partially hydrogenated oils are less likely to go rancid because

they have fewer double bonds

The intake of ____ fat should be kept as low as possible as recommended by Dietary Guidelines for Americans, the American Heart Association, and the Food and Nutrition Board

trans

High levels of HDL in the blood tend to slow the development of cardiovascular disease because HDL

transports cholesterol from the bloodstream to the liver for excretion

A recipe may have to be adjusted when substituting reduced-fat margarines for regular margarine because of the added _____ in the reduced-fat margarine

water

If you witnessed a person experiencing shortness of breath, nausea and vomiting, irregular heartbeat, sweating, and radiating pain in the upper body, you would suspect that this person is having a(n) _____.

Heart attack

Butter and margarine have about the same amount of fat, but the types of fatty acids and are margarine are different. Compared to margarine, butter has a ____ proportion of saturated fatty acids.

Higher

What is the chemical structure of an omega-3 fatty acid?

It contains the first carbon-carbon double bond on the third carbon from the omega end of the carbon chain.

How does the body respond when it is attempting to store fat and the existing fat cells are "full"?

It forms new adipose cells

Fat free definition

Less than 0.5g of fat per serving

What are the values for HDL and total cholesterol, respectively, that serve as risk factors for development of cardiovascular disease?

Less than 40 mg/dL; greater than 200 mg/dL in fasting state

Glycerol, fatty acids, and phosphorus-containing parts are all byproducts of _____ digestion

Phospholipid

Working as emulsifiers, important to the proper functioning of the nervous system, and having the ability to be soluble in fat and water are all function of

Phospholipids

Systolic Blood Pressure

Pressure in the arterial blood vessels associated with pumping of the blood from the heart

Diastolic Blood Pressure

Pressure in the arterial blood vessels when the heart is between beats

HDL primary component

Protein

_____ occurs when the double bonds in unsaturated fatty acids in food products are broken down by ultraviolet light or oxygen.

Rancidity

_____ reduces the shelf life of a product creating a problem for the food industry and restaurants. To prevent the problem, manufacturers add partially hydrogenated plant oils to products.

Rancidity

Phytosterols are plant chemicals that

Reduce cholesterol absorption in the small intestine

______ serve to stop the damage down to cells by oxidation

Antioxidants

Monounsaturated and polyunsaturated fatty acids are typically liquid at room temperature

True

Monounsaturated, saturates, and polyunsaturates fats all provide the same number of calories

True

Once a fat cell is filled with fat, the body can form new adipose cells

True

The CLA or natural trans fats decrease the risk of heart disease, cancer, and obesity

True

The body is able to produce all of the phospholipids it needs in order to maintain normal physiological function.

True

The process of oxidation usually changes the shape and/or function of a substance

True

What are some of the risk factors for cardiovascular disease?

-Smoking -High blood cholesterol -Family history of cardiovascular disease -Hypertension

Phytosterols are plant chemicals that can reduce blood cholesterol. They can be found in

-Speciality margarines and salad dressings -Pistachios and sunflower seeds -Pill form

Typical warning signs of a heart attack include

-Irregular heartbeat -Shortness of breath -Intense, prolonged chest pain or pressure, sometimes radiating to other parts of the upper body.

Which statements are true about a monoglyceride?

-It consists of one fatty acid bonded to a glycerol backbone -It is one of the products of digestion of triglycerides

Which of the following food sources are high in saturated fat?

-Cheeseburger -Butter -Coconut oil

What is the function of an emulsifier?

Suspends fats in water

Why is LDL considered "bad" cholesterol?

-Buildup of LDL in blood vessels contributes to atherosclerosis, a process that increases the risk of developing cardiovascular disease. -If not cleared from the bloodstream, LDL cholesterol builds up in the blood vessels

Just because a food is high in fat does not mean it is unhealthy. Some high-fat foods, such as plant oils and nuts, should be included in the diet because they are sources of

-Essential fatty acids -Fat-soluble vitamins

Characteristics of cholesterol:

-It is used for making estrogen and testosterone -It is converted to bile -It is incorporated into cell membrane

What are some examples of foods that are cholesterol-free?

-Margarine -Vegetable oil -Peanut butter -Vegetable shortening

How are the different types of fatty acids distinguished?

-Number of carbon-carbon double bonds along the skeleton -Length of the carbon skeleton -Position of carbon-carbon double bonds along the skeleton

In the listing of ingredients on a food label, the presence of _____ is an indication that a product is a source of trans fat.

-Partially-hydrogenated oils -Margarine

Which statements are true about omega-6 fatty acids?

-They are also called unsaturated fatty acids -The first carbon-carbon double bond is on the sixth carbon from the methyl end of the carbon chain

Which statements are true about sterols?

-They contain a multi-ring structure -Cholesterol is a common example -They can be produced by the body

What are some food sources of EPA and DHA?

-Tuna -Sardines -Salmon

Which of the following are true in terms of triglyceride digestion and absorption?

-Two outer fatty acids are removed prior to absorption -Digestion primarily occurs in the small intestine via pancreatic lipase -Fatty acids and monoglycerides are absorbed by the intestinal cells

List the steps of fat digestion and absorption starting in the mouth (top of the list) and ending in the small intestine

1) Some lipase is released by the salivary glands and stomach 2) Salivary lipase and gastric lipase begin digesting short-chain fatty acids in the stomach 3) Bile emulsified the fats 4) Pancreatic lipase digests long-chain fatty acids and triglycerides 5) Triglycerides are broken down and absorbed in the small intestine

Polyunsaturated fat food sources

Corn oil, fish oil, sunflower oil, safflower oil

Omega-3 Classification

Essential fatty acid; alpha-linolenic acid

Linoleic acid and alpha-linolenic acid are both

Essential fatty acids

Phospholipids are essential parts of only a few types of cells, like adipose and liver cells

False

Which of the following has only carbon-carbon single bonds?

Saturated fatty acid

What is the primary health risk associated with a high intake of trans fat?

Increased risk of heart disease

Why are triglycerides ideal for fat storage?

-They are chemically stable -They are energy dense

In terms of HDL and LDL levels, risk for development of cardiovascular disease increases when _____ level are low and _____ levels are high in the bloodstream

HDL; LDL

Formed from the breakdown of triglycerides, a _____ consists of one fatty acid attached to a glycerol backbone

Monoglycerides

Sterol structure

Multi-ringed compound with a hydroxyl group

Quantity fat recommendation

Need not be altered to maintain a healthy diet

Quality fat recommendation

Needs to be increased by choosing fewer saturated and trans fatty acids

Monounsaturated fat food sources

Olive oil, canola oil, peanut oil

Considering their health effects, trans fatty acids are most similar to

Saturated fatty acids

A _____ is a lipid with a multi-ringed structure

Sterol

Omega-6 molecular structure

The first carbon-carbon double bond is located on the sixth carbon from the omega, or methyl, end of the structure

Omega-3 molecular structure

The first carbon-carbon double bond is located on the third carbon from the omega, or methyl, end of the structure