NUTR 202 Exam 2 PART 1

Lipids (are what)

category of compounds containing carbon, hydrogen, and oxygen that are hydrophobic

what does hydrophobic mean

insoluble in water

Fats serve multiple functions in foods:

▪ Give flaky texture to baked goods

▪ Make meats tender

▪ Provide flavor and aromas

▪ Contribute to satiety

Fat is the common name for just one type of lipid, known as a

triglyceride

Fats and other lipids perform important functions in the body such as

– Energy storage

– Insulation

– Transport of compounds in blood

– Cell membrane structure

What are the three types of lipids found in foods and in your body

Triglycerides (fats), phospholipids, and sterols

What is the basic unit of triglycerides and phospholipids

fatty acid

Fatty acids (structure)

chain of carbon and hydrogen atoms with acid group (COOH at one end)

What are the three main types of fatty acids?

-Saturated fatty acids

-Monounsaturated fatty acids (MUFAs)

—Polyunsaturated fatty acids (PUFAs)

Saturated fatty acids

all carbons bonded to hydrogen

▪ For example, stearic acid, 18 carbons, solid at room temperature

Monounsaturated fatty acids (MUFAs)

one double bond

▪ For example, oleic acid, 18 carbons (olive oil), liquid at room temperature

Polyunsaturated fatty acids (PUFAs)

more than one double bond

▪ For example, essential fatty acids linoleic acid and alpha-linolenic acid (soybean oil)

Triglyceride (structure)

three fatty acids connected to glycerol “backbone”

_____ is the most ____ lipid found in foods and body

triglyceride; common

Oils are fats that are

liquid at room temperature

Phospholipids (structure)

have glycerol backbone, but two fatty acids and a phosphorus group

Phosphorus-containing head is

hydrophilic

Major phospholipid in cell membrane

lecithin

Lecithin used as an

emulsifier in foods such as salad dressings to keep oils and water mixed together

lipids usually refer to

fats (solids at room temp)

oil

Sterols are composed mainly of

Sterols are composed mainly of

Cholesterol is an example of what

a STEROL

Important role in cell membrane structure

▪ Precursor of important compounds in body

– Converted into vitamin D and other substances

Is cholesterol required in your diet?

Not required in diet since body makes all cholesterol needed

Lecithin is an example of what kind of lipid

an example of a phospholipid

Fat digestion (mouth)

chewing and lingual lipase start digestion

Fat digestion (stomach)

gastric lipase breaks down fat into diglyceride and one fatty acid

most digestion of fat occurs where?

in the small intestine

fat digestion (small intestine)

-Bile acids: emulsify fat, break fat globules into smaller pieces

– Cholecystokinin is the hormone that stimulates the pancreas

– Pancreatic lipase: two fatty acids and monoglyceride

– Lecithin in bile is packaged with monoglycerides and fatty acids to create micelles (small carriers) for absorption

– Short-chain fatty acids enter bloodstream and travel to liver

– Long-chain fatty acids enter lymph and need transport carriers

After the stomach, short0chain fatty acids go where

enter the bloodstream and travel to the liver

After the stomach, long-chain fatty acids

enter the lymphatic system, lymph and need transport carriers

Fat digestion (liver)

produces bile

Fat digestion (pancreas)

produces pancreatic lipase, which is then secreted in the small intestine to turn fats into two fatty acids and monoglyceride

What Happens to the Fat You Eat? (Lipoproteins)

transport fat through the lymph and blood

What Happens to the Fat You Eat? (Chylomicrons; a type of lipoprotein)

carry digested fat through lymph into bloodstream

What Happens to the Fat You Eat? (Very low-density lipoproteins VLDL; a type of lipoprotein)

deliver fat made in liver to cells

What Happens to the Fat You Eat? (Low-density lipoproteins LDL; a type of lipoprotein)

AKA BAD CHOLESTEROL

deposit cholesterol on walls of arteries

What Happens to the Fat You Eat? (High-density lipoproteins HDL; a type of lipoprotein)

AKA GOOD Cholesterol

remove cholesterol from body and deliver to liver for excretion

What two polyunsaturated fatty acids are essential? and their function

-linoleic acid (an omega-6 fatty acid)

-alpha-linolenic acid (an omega-3 fatty acid)

The essential fatty acids help maintain healthy skin cells, nerves, and cell membranes and are precursors to eicosanoids, eicosapentaenoic acid, and docosahexaenoic acid

Eicosanoids

hormone-like substances made from essential fatty acids, which are involved in inflammation, blood clotting, blood pressure

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)

two omega-3 fatty acids that are heart-healthy

EX: Fatty fish such as salmon, herring, and sardines are rich sources

Cholesterol has many important roles

– Part of cell membranes

– Precursor for vitamin D, bile acids, sex hormones

AMDR of DRI (for fat)

20 to 35 percent of total daily calories should come from fat

Saturated fat consumption recommendation

For heart health, you should consume less than 10 percent (ideally less than 7 percent) of your calories from saturated fats

calculating grams of fat intake based on AMDR (20-35%)

ask chat for some examples

You should minimize _____ fat and _____ fat in your diet

saturated; trans

Trans fats are created through the process of

hydrogenation

▪ They resist randicidity (the breakdown or spoiling of fats and oils that causes a bad smell and foul taste) and increase shelf life

Which is worst, trans fat or saturated fat

Trans;

▪ Raise LDL (bad) cholesterol and lower HDL (good) cholesterol

▪ The FDA banned partially hydrogenated oil in processed foods..

Does you NEED to consume cholesterol in your diet?

no, Your body makes all the cholesterol it needs.

-also food cholesterol DOES NOT determine blood pressure

Foods that contain unsaturated fats (both monounsaturated and polyunsaturated fats) are

better for your health than foods high in saturated fat, and/or cholesterol

Which fat is the BEST

Monounsaturated fats are the best

Sources of monosaturated fats

peanut oil, canola oil, and olive oil as well as nuts and avocados

Fat substitutes are designed to

provide all the creamy properties of fat for fewer calories and total fat grams

Because fat has more than double the calories per gram of carbohydrates or protein, fat substitutes have the potential to reduce calories from fat by more than 50 percent

Fat substitutes can be carbohydrate-, protein-, or fat-based

The majority are carbohydrate-based and use plant polysaccharides

Heart disease begins with

a buildup in the arteries

Atherosclerosis

narrowing of coronary arteries due to buildup of plaque (hardened debris of cholesterolladen foam cells, platelets, and other substances)

atherosclerosis increases the chance of

blood clots blocking the vessel, causing heart attack or stroke

risk factors for heart disease (you can’t control)

age

gender

family history

type 1 diabetes

risk factors for heart disease (you can control)

– Regular exercise can help lower LDL and raise HDL – Losing excess weight and quitting smoking can help increase HDL levels.

Metabolic syndrome

group of risk factors that increase the risk of heart disease

– Insulin resistance, high blood pressure, centralized obesity, low HDL, and high triglycerides

What Can You Do to Maintain Healthy Blood Cholesterol Levels to Reduce Your Risk of Heart Disease?

1. Minimize saturated fats, trans fats, cholesterol in diet

2. Include fish in your weekly choices

3. Eat plenty of plant foods

4. Select foods rich in antioxidants and phytochemicals

5. Strive for plenty of exercise and manage your weight

6. Moderate use of alcohol may reduce risk of heart disease, but some should avoid alcohol

7. The whole is greater than the sum of its parts

Fabulous! Keep up the good work level of TOTAL cholesterol

less than 200

Traditional diet of Mediterranean region is associated with

lower risk of heart disease and cancer

– Plant-based diet of whole grains, fruits, vegetables, legumes, and nuts

▪ With olive oil, low-fat dairy, water

▪ Occasional, poultry, eggs, meat, sweets, wine

Methylmercury is a

toxic chemical especially harmful to the nervous systems of unborn children

Methylmercury is found in larger fish with a longer life span such as

swordfish

shark

king mackerel

tilefish

Who should avoid the fish high in Methylmercury (swordfish, shark, king mackerel, tilefish)

Women of childbearing age and young children

Canned albacore tuna has more

mercury than light tuna

What is one of the easiest ways to decrease LDL

Eating more plant foods high in soluble fiber

Although all plant foods are cholesterol free, they do contain

phytosterols, which are plant sterols similar to cholesterol found in the plant's cell membranes

Plant sterols can help lower LDL cholesterol levels by

competing with cholesterol for absorption in the intestinal tract

Sources of sterols include

soybean oil

many fruits

vegetables

legumes

sesame seeds

nuts

cereals and other plant foods

Flavonoids are

phytochemicals found in fruits, vegetables, tea, nuts, and seeds that may offer some antioxidant protection as well as potentially inhibiting platelet aggregation, which can perpetuate a blood clot

To Decrease Excess LDL Cholesterol

read this

Is Coconut Oil Healthy for You? (cons)

– Olive oil also has phytochemicals and is heart-healthy

– Coconut oil is high in saturated fat

Olive oil is a better option

Proteins are the predominant

structural and functional materials in every cell

what differentiates protein from carbohydrates and fats

they contain Nitrogen

(protein) Each amino acid has

▪ Acid group (COOH)

▪ Amine group (NH2)

▪ Side chain (unique)

All proteins consist of a chain of some combination of 20

unique amino acids

An acid group and amine group are connected by

peptide bonds to create dipeptides

Nine essential amino acids

– Cannot be made by the body

– It is “essential” to obtain them from the diet

Eleven nonessential amino acids

Can be synthesized in the body from other amino acids or by adding nitrogen to carbon-containing structures

Conditionally essential amino acids

Under certain conditions, some nonessential amino acids cannot be synthesized and must be consumed in the diet

What is the basic building block of protein

amino acids are the basic building block

Denaturation:

the alteration (unfolding) of a protein's shape, which changes the structure and function of the protein

examples of denaturation

-cooking meat, eggs changing texture

– Stomach acid untangles proteins to aid in digestion

Protein digestion (stomach;HCL)

denatures protein and activate pepsin

Protein digestion (stomach; pepsin)

enzyme in stomach that begins breaking down protein

Protein digestion (small intestine; Cholecystokinin)

stimulates the release of pancreatic enzymes

Protein digestion (small intestine; Proteases)

(from the pancreas) digest polypeptides to form shorter remnants for absorption

In the small intestine, polypeptides are broken down into

tripeptides, dipeptides, and amino acids

– Amino acids travel to the liver

Amino acids come from

– Diet

– Breakdown of proteins in the body

– A limited supply is stored in amino acid pools in blood and cells for needed protein synthesis

Protein turnover

process of continuous breakdown and synthesis of protein from its amino acids

amine groups are removed/ converted to

urea, excreted in urine

fter amine groups are removed (converted to urea, excreted in urine), amino acids can also be: (BSM)

– Burned for energy

– Stored as fat

– Made into glucose

Gene

DNA segment that codes for specific protein

Messenger RNA (mRNA) and transfer RNA (tRNA) perform

very specific roles during protein synthesis

When abnormalities occur during protein synthesis, serious medical conditions may result such as

sickle-cell anemia

What is sickle cell anemia

Illness that results from malformation of red blood cell because of an incorrect structure in part of its hemoglobin protein chains

Proteins provide structural and mechanical support and help maintain

body tissues (such as collagen and connective tissue)

Collagen:

a ropelike, fibrous protein that is the most abundant protein in your body

Connective tissue

the most abundant tissue type in the body; made up primarily of collagen, it supports and connects body parts as well as providing protection and insulation