StraighterLine Intro to Nutri 101 Quiz 5 Lipids

low-density lipoprotein (LDL)

"bad cholesterol"; transports cholesterol from the liver to the body tissues

high-density lipoprotein (HDL)

"good cholesterol" in the blood, which protects against cardiovascular disease

total parenteral nutrition

The intravenous feeding of all necessary nutrients, including the most basic forms of protein, carbohydrates, lipids, vitamins, minerals, and electrolytes.

very-low-density lipoprotein (VLDL)

The lipoprotein created in the liver that carries cholesterol and lipids that have been taken up or newly synthesized by the liver.

triglyceride

The major form of lipid in the body and in food. It is composed of three fatty acids bonded to glycerol, an alcohol

hydrogenation

The process of converting unsaturated fats to saturated fats by adding hydrogen

cholesterol

A waxy lipid found in all body cells. It has a structure containing multiple chemical rings that is found only in foods that contain animal products.

What are some compounds that are made from cholesterol in the body?

It forms part of some important hormones, such as estrogen, testosterone, and a precursor of the active vitamin D hormone. Cholesterol is an essential structural component of cells and the outer layer of the lipoprotein particles that transport lipids in the blood. The cholesterol content of the heart, liver, kidney, and brain is high, reflecting its critical role in these organs. Cholesterol is also the building block of bile acids, needed for fat digestion.

What enzyme is responsible for digestion of triglycerides?

In the small intestine, triglycerides are broken down by lipase into smaller products, namely monoglycerides (glycerol backbones with a single fatty acid attached) and fatty acids.

foam cells

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

What is the limit for cholesterol intake?

The recommended daily intake of dietary cholesterol for the average healthy person is about 300 milligrams per day with less than seven per cent of calories coming from saturated fat.

In what ways do fatty acids differ from one another?

They come in different chain lengths: -Short chain FA (SCFA), less than 6 carbons long. -Medium chain FA (MCFA), 6-10 carbons long. -Long Chain FA (LCFA), 12-22/24 carbons long.

What is the common property that all lipid compounds share?

They do not readily dissolve in water

monounsaturated fatty acid

a fatty acid containing one point of unsaturation

long-chain fatty acid

a fatty acid that contains 12 or more carbons

polyunsaturated fatty acid

a fatty acid with two or more points of unsaturation

phospholipid

a lipid that contains phosphorus and that is a structural component in cell membranes

Immediately after a meal, newly digested and absorbed dietary fats appear in the lymph and then the blood as part of which of the following?

chylomicrons

lipoproteins

clusters of lipids associated with proteins that serve as transport vehicles for lipids in the lymph and blood

atherosclerosis

hardening of the arteries

myocardial infarction

heart attack

Of the macronutrients, fats are the most significant dietary factor(s) associated with _________________.

heart disease

High blood concentrations of _____ decrease the risk for cardiovascular disease.

high-density lipoproteins

Margarine usually is made by a process called_____, in which hydrogen atoms are added to carbon-carbon double bonds in the polyunsaturated fatty acids found in vegetable oils.

hydrogenation

cis fatty acid

hydrogens are on the same side of the fatty acid backbone

What are the end products of fat digestion?

monoglycerides, diglycerides, glycerol, fatty acids

hemorrhagic stroke

occurs when a blood vessel in the brain leaks or ruptures; also known as a bleed

Essential fatty acids that cause a decrease in blood clotting are

omega-3

Which of the following groups of foods would be important sources of saturated fatty acids?

palm oil, palm kernel oil, coconut oil

lipase

pancreatic enzyme necessary to digest fats

The main problem with the fat replacer olestra is that it can bind

the fat-soluble vitamins and reduce their absorption.

systolic blood pressure

the pressure created when the heart contracts and forces blood out into the arteries

menopause

the time of natural cessation of menstruation; also refers to the biological changes a woman experiences as her ability to reproduce declines

oxidize

to combine with oxygen

Lipoproteins are important for

transport of fats in the blood and lymphatic system

The body stores excess protein as

triglycerides

One of the richest plant sources of omega-3 fatty acids, alpha-linolenic acid, and also a good source of plant sterols is

walnuts

Which foods are the most fat-dense (>60% total calories as fat)?

whole foods highest in fat include nuts, bologna, avocados, and bacon, which have about 80% of calories as fat. Next, peanut butter and cheddar cheese have about 75%. Marbled steak and hamburgers (ground chuck) have about 60%

saturated fatty acid

A fatty acid containing no carbon-carbon double bonds

docosahexaenoic acid (DHA)

A metabolic derivative of alpha-linolenic acid; together with EPA, it appears to reduce the risk of heart disease.

lecithin

A phospholipid manufactured by the liver and also found in many foods; a major constituent of cell membranes.

antioxidant

A substance that slows down oxidation, foods include blueberries and green vegetables.

glycerol

A three-carbon alcohol to which fatty acids are covalently bonded to make fats and oils.

Which of the following foods is the best source of omega-3 fatty acids?

fatty fish

rancid

(adj.) stale, spoiled

monoglyceride

A breakdown product of a triglyceride consisting of one fatty acid attached to a glycerol backbone.

diglyceride

A breakdown product of a triglyceride consisting of two fatty acids bonded to a glycerol backbone.

plaque

A deposit of fatty material on the inner lining of an arterial wall

emulsifier

An ingredient that brings two normally incompatible materials together and binds them into a uniform and fairly stable blend.

oleic acid

An omega-9 fatty acid with 18 carbons and one double bond.

omega-6 (ω-6) fatty acid

An unsaturated fatty acid with the first double bond on the sixth carbon from the methyl end (-CH3).

omega-3 (ω-3) fatty acid

An unsaturated fatty acid with the first double bond on the third carbon from the methyl end (-CH3).

Where do the LDLs originate and what is their destination?

As its triglycerides are released, the VLDL becomes proportionately denser. Much of what eventually remains of the VLDL fraction is then called low-density lipoprotein (LDL); this is composed primarily of the remaining cholesterol. The primary function of LDL is to transport cholesterol to tissues. LDL particles are taken up from the bloodstream by specific receptors on cells, especially liver cells, and are then broken down. The cholesterol and protein components of LDL provide some of the building blocks necessary for cell growth and development, such as synthesis of cell membranes and hormones.

What are the main functions of cholesterol in the body?

Cholesterol is essential for making the cell membrane and cell structures and is vital for synthesis of hormones, vitamin D and other substances.

Where is cholesterol found in the food supply?

Cholesterol is found only in animal foods. Some plants contain other sterols similar to cholesterol, but they do not pose the heart health risks associated with cholesterol. In fact, some plant sterols have blood cholesterol-lowering properties

How do fats become rancid, and how can this be prevented?

Decomposing oils emit a disagreeable odor and taste sour and stale. The double bonds in unsaturated fatty acids break down, producing rancid by-products. Ultraviolet light, oxygen, and heat (as in deep-fat frying) can break double bonds and, in turn, destroy the structure of polyunsaturated fatty acids.

What happens to unsaturated fats during the process of hydrogenation?

If oils with unsaturated fatty acids are used to replace solid fats, they often must be made more saturated (with hydrogen), as this solidifies the vegetable oils into shortenings and margarines. Hydrogen is added by bubbling hydrogen gas under pressure into liquid vegetable oils in a process called hydrogenation

How does the percent of calories as fat in the North American diet compare to recommendations?

In summary, the general consensus among nutrition experts suggests that limitation of saturated and trans fat intake should be the primary focus and that the diet needs to contain a balance of omega-3 and omega-6 fatty acids, if fat intake exceeds 30% of total calories, the extra fat should come from monounsaturated fat, primarily olive oil.

After chylomicrons leave the intestinal cells, they are transported via what system?

Lymphatic

Why are HDLs considered "good" cholesterol?

Many studies demonstrate that the amount of HDL in the bloodstream can closely predict the risk for cardiovascular disease. Risk increases with low HDL because little cholesterol is transported back to the liver and excreted.

Where are phospholipids found in the body?

Molecules of cell membranes

Which types of fat are used as emulsifiers, and what is their function in food?

Phospholipids such as lecithin, is used as an emulsifier in these and other products because of its ability to keep mixtures of lipids and water from separating

What are the four possible structural forms of lipid?

Phospholipids, triglycerides, sterols, and fatty acids/ triglycerides

diastolic blood pressure

Pressure in the arteries when the heart relaxes and ventricles fill with blood

What are the characteristics of the Mediterranean diet?

Reduction of cardiovascular disease has been one of the most consistent results of the Mediterranean diet. The major sources of fat in the Mediterranean diet include liberal amounts of olive oil compared to a small amount of animal fat (from animal flesh, eggs, and dairy products). In contrast, major sources of fat in the typical North American diet include animal flesh, whole milk, pastries, cheese, margarine, and mayonnaise. While dietary fat sources definitely play a role in prevention of chronic disease, it is important to remember that other aspects of one's lifestyle also contribute to disease risk. People who follow a Mediterranean diet also tend to consume moderate alcohol (usually in the form of red wine, which contains many antioxidants), eat plenty of whole grains and few refined carbohydrates, and are also more physically active than typical North Americans

What is the difference between a saturated and an unsaturated fatty acid, and between an omega-3 and an omega-6 fatty acid?

Saturated fatty acids lack double bonds between the individual carbon atoms, while in unsaturated fatty acids there is at least one double bond in the fatty acid chain. Saturated fats tend to be solid at room temperature and from animal sources, while unsaturated fats are usually liquid and from plant sources. The only difference is that the last double bond is six carbons from the omega end of the fatty acid molecule. Omega-6 fatty acids are also essential, so you need to obtain them from your diet.

What regulations are in place to educate and protect the public from trans fats in foods?

Since 2006, federal regulations have required the disclosure of trans fat content on food packages. In 2013, FDA proposed a change to the way trans fats are regulated in the United States. If approved, food manufacturers would no longer be able add trans fats to food products. One state (California) and several localities (e.g. New York City) have passed legislation to ban trans fat use in food service establishments FDA's recently proposed legislation would prevent restaurants from purchasing partially hydrogenated oils with trans fats.

scavenger cells

Specific form of white blood cells that can bury themselves in the artery wall and accumulate LDL. As these cells take up LDL, they contribute to the development of atherosclerosis.

What are the differences between the absorption of long- versus short-chain fatty acids?

The chain length of fatty acids affects the ultimate fate of fatty acids and monoglycerides after absorption. If the chain length of a fatty acid is less than 12 carbon atoms, it is water soluble and will therefore probably travel as such through the portal vein that connects directly to the liver. If the fatty acid is a more typical long-chain variety, it must be reformed into a triglyceride in the intestinal absorptive cell and eventually enter circulation via the lymphatic system

What are some strategies used to produce reduced-fat foods?

To lower the fat in foods, manufacturers may replace some of the fat with water, protein (Simplesse®, Dairy-Lo®), or forms of carbohydrates such as starch derivatives (Z-trim®), fiber (Maltrin®, Stellar™, Oatrim), and gums. Manufacturers also may use engineered fats, such as olestra (Olean®) and salatrim (Benefat®), that are made with fat and sucrose (table sugar) but that provide few or no calories because they cannot be digested and/or absorbed well.

What are the functions of triglycerides in the body?

Triglycerides are used for energy storage, insulation, and transportation of fat-soluble vitamins.

How do triglycerides differ from phospholipids?

a triglyceride contains three fatty acids attached to the glycerol backbone, while a phospholipid has two fatty acids plus a phosphate group attached to the glycerol.

sterol

a type of lipid with a structure composed of multiple chemical rings

cerebrovascular accident (CVA)

a.k.a. "Stroke". Lack of blood supply to the brain causing brain damage

Which fatty acids are essential?

alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid)

An essential omega-3 fatty acid with 18 carbons and 3 double bonds is called

alpha-linolenic acid.

lipoprotein lipase

an enzyme that sits on the outside of cells and breaks apart triglycerides, so that their fatty acids can be removed and taken up by the cell

alpha-linolenic acid

an essential omega-3 fatty acid

linoleic acid

an essential polyunsaturated fatty acid of the omega-6 family

Cholesterol is

an important part of human cell membranes and necessary to make some hormones.

eicosapentaenoic acid (EPA)

an omega-3 fatty acid available from marine foods and as a metabolic derivative of alpha-linolenic acid

arachidonic acid

an omega-6 fatty acid derived from linoleic acid

trans fatty acid

an unsaturated fatty acid in which the hydrogen atoms are on the opposite sides of the double bond

Phospholipids such as lecithin are used extensively in food preparation because they

are excellent emulsifiers

eicosanoids

biologically active compounds that regulate body functions

Lipoproteins contain all of the following components except

carbohydrate.

How are dietary fats packaged in the small intestine and transported?

digestion of dietary fats results in a mixture of glycerol, monoglycerides, and fatty acids. Once these products are absorbed by the cells of the small intestine, they are reassembled into triglycerides. Then, the intestinal cells package the triglycerides into chylomicrons, which enter the lymphatic system and eventually the bloodstream. Chylomicrons are the largest lipoproteins and contain dietary fat and originate only from the intestinal cells. Like the other lipoproteins, chylomicrons are composed of large droplets of lipid surrounded by a thin, water-soluble shell of phospholipids, cholesterol, and protein

chylomicrons

fat droplets covered in protein that diffuse into capillaries in small intestine

Pancreatic lipase digests

fats

essential fatty acids

fats needed by the body that must be consumed in the diet because the human body cannot manufacture them

solid fats

fats that are high in saturated fat and usually not liquid at room temperature. Some common solid fats include butter, beef fat, chicken fat, pork fat, stick margarine, coconut oil, palm oil, and shortening.

In the small intestine, the pancreas secretes ____________ to digest triglycerides.

lipase

How do lipids move through the bloodstream?

lipoproteins

To be transported throughout the body, fats are packaged in structures called

lipoproteins

Where are VLDLs made and what do they contain?

lipoproteins made by the liver are very-low-density lipoproteins (VLDL). These particles are composed of cholesterol and triglycerides surrounded by a water-soluble shell. VLDLs are rich in triglycerides and thus are very low in density. Once in the bloodstream, lipoprotein lipase on the inner surface of the blood vessels breaks down the triglyceride in the VLDL into fatty acids and glycerol. Fatty acids and glycerol are released into the bloodstream and taken up by the body cells.

The main form of lipid found in the food we eat is

plant sterols.

BHA, BHT

preservatives commonly used to slow the development of "off" flavors, odors, and color changes caused by oxidation