NUTR Exam 2

what are lipids?

* substances that are insoluble in water
* soluble in organic solvents (acetone and chloroform)

3 main categories of lipids

1. triglycerides
2. phospholipids (emulsifier)
3. sterols (ex. cholesterol, vitamin D, sex hormones)

what are lipids comprised of?

* carbon
* hydrogen
* oxygen

what is the difference between carbs and lipids?

* double bonds and twice as many hydrogens
* 9kcal/gram in lipids

what groups are on a fatty acid chain?

carboxyl group and methyl group

what does the carboxyl group do

hydrophilic

what does the methyl group do

hydrophobic

what are fatty acids components in?

phospholipids and triglycerides

if carbon chain is fully occupied by hydrogen atoms it is a

saturated fatty acid

unsaturated fatty acid

fatty acid with one or more double bond

monounsaturated fatty acid

fatty acid with one double bond

polyunsaturated fatty acid

two or more double bonds

what state is saturated fat at room temp

solid

what state us mono and poly saturated at room temp

liquid

essential fatty acids

cant be made by the body and need to be provided by diet

what are the two families of fatty acids

1. omega 6


1. linoleic acid
2. omega 3


1. linolenic acid

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omega 6 factors

* incorporated into cell membranes
* precursors to compounds involved in reproduction and blood flow
* ex. arachidonic acid

omega 3 factors

* in cell membranes
* help prevent tissue inflammation
* eicosapentanoic acid
* docosahexanoic acid
* may help prevent heart disease and blood clot formation

trans fatty acid (man-made/synthetic)

produced through addition of hydrogen atoms to double bonds of fatty acids

hydrogenation

* process of adding hydrogens to unsaturated fats
* making solid at room temp
* common dietary sources (cake, cookie, crackers)
* small amounts are found in (dairy milk and meat)

only some unsaturated fats converted to saturated fats via hydrogenation

partially hydrogenated (butter in a carton)

increased level of bad or low density lipoprotein

LDL

reduced levels of good or high density lipoprotein

HDL

chemical structure of a triglyceride

a three carbon glycerol backbone

three fatty acids

what do triglycerides in the body reflect

dietary fatty acids consumed

phospholipids

compounds that assist the body in transporting fat through watery substance

chemical structure of phspholipids

three-carbon glycerol backbone

two fatty acids bound to its first two carbons

third carbon has a phosphate group bound to it

properties of phospholipids

hydrophilic and hydrophobic

what do phospholipids function as

emulsifiers: blending of water and fat components

what body parts are phospholipids components of

cell membrane

lipoproteins

* transport particle of fat in the body (cholesterol (animal products) and triglycerides)

what are lipid function?

flavor and satiety

storage of energy as fat tissue

steroid hormone production

absorption of fat-soluble vitamins by small intestine

cell membrane structure

organ protection (fat around kidneys)

essential fatty acids (can protect heart)

lipids are the primary source of energy for

heart

what are the two essential fatty acids

linoleic acid and linolenic acid

what do eicosanoids do

relaxing blood vessels and promoting clotting

what is fat required for the absortion of?

fat-soluable vitamins (vitamins ADEK)

when does fat soluable vitamin absortion decrease?

when there is incomplete fat absortion or fat malabsorption

what does fat do for the body

protects and insultes vital organs

do males or femals have greated percentage body fat

females

what are major components of the cell membranes?

phospholipids and cholesterol

what are hormoe examples

estrogen

testosterone

aldosterone

what vitamine has ahorme-like function

vitamin D

what role does fat have in foods?

mouthfeel, texture, flavor compounds interact with fat molecules in food

why does fat cause you to feel full for a longer time?

satiety, fat slows stomach emptying, enhances flavor compounds, dietary fat and weight management?

examples of saturated fatty acids

* beef, prok, pultry with skin and other meat
* cheese, butter, and other dairy products
* palm and cocunt ouls (tropical oils)

examples of unsaturated fats

* vegtable oilds
* nuts and seeds
* fish

where is choleterol

animal products on the human diet

carbohydrate-based fat replacors

* add creaminess, bulkiness, and moistness
* maltodextrins, modified food starches, cellulose, and gums
* 1-4 kcal per gram

protein based fat replacers

* denature under high heat
* used in frozen desserts
* 4 kcal per gram

fat-based fat replacers

* non-digestible/partially digested
* contribute to taste, texture, and mouthfeel
* side effects
* reduced ADEK absorption
* loose stools
* abdominal cramps

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fat blockers

marketed as weight loss drugs

* disrupt intestinal fat absorption (inhibit digestive enzyme that breaks down triglycerides

side effects of fat blockers

anal leakage

reduced fat-soluble vitamin ADEK absorption

malabsorption of oral contraceptives

modifiable risk factors of heart disease

* high blood pressure
* high cholesterol
* cigarette smoking
* diabetes
* poor diet and physical inactivity
* overweight and obese

what is the leading cause of death in the US for men and women?

heart disease

what fat should decrease due to heart disease

saturated and trans fat

cardiovasular diease

primary type of heart disease linked with fat intake is atherosclerosis

* build up of fatty deposits and streaks in the ateries
* may reduce blood flow to areas in the heart caused ischemia

what is it called when artery is blocked?

myocardial infarction or heart attack

what is a stroke?

slockage of atery supplying blood to brain

what are lipoproteins?

spherical structure that are composed of lipids and proteins

* transport lipid particles in the body
* outer shell is monolayer

what property allows lipoproteins to transport lipids in the body?

shape!

* outer portion to associate with water portion (blood)
* inner incorporate cholesteral - to move fat soluable vitamins through the body

4 types of lipoproteins

1. cholymicrons
2. VLDL
3. LDL


1. HDL

chylomicrons

* made in cells of small intestine
* transport dietary lipids to the liver

very low-density lipoproteins

* synthesized in the liver
* contain both triglycerides and cholesterol
* deliver triglycerides to other tissue

low density lipoproteins

* formed after VLDLs deposit triglycerides to other tissue
* cholesterol rich
* deliver cholesterol to other tissues. including blood vessels
* “bad cholesterol”

high density lipoproteins

* made mostly in the liver but also in the small intestine
* removes excess cholesterol from cells
* return to liver for elimination
* “good cholesterol”

USDA’s 2015 dietary guidlines for americans (lipids/fats)

* 20-35% of daily calorites from fat
* fat intake below range not recommended
* decreased absorption of fat-soluable vitamins

Child under the age of 2 (lipids/fats)

* 30-35% calories from fat
* growth and nervous system development depend on adequate fat intake

redulce saturated fat to

less than 10%

what cna you replace sat fat with

plyunsaturated and monounsaturated fatty acids

minimized trans and hydrogenated fats examples

* crackers

snack foods

ready made cakes and cookies

margarine, shortening

eat less of:

* high fat meat, pork, lamb, pultry with skin on
* cheese and whole fat dairy
* processed meats
* butter, margarine

eat more of:

* fruits vegetable whole grains
* nuts seeds
* liquid veg oil
* lean meat, pork, lamb, poultry without skin and fatty fish

other risk factors

* 150 min of moderate of 75 min of vigorous activity each week
* maintain or attain a healthy weight
* stop smoking
* alcohol moderation
* 1-2 drinks for males daily
* 1 drink for females daily

is the obesity epidemic in the US connected with an increased fat intake?

* % of cal from fats in our diet has decreased over the last two decades
* low fat diets may promote weight loss
* those who follow Mediterranean diet are less obese
* diet is not lower fat
* 35% of calories from fat

what types of fatty acids influence the risk of cnacer?

* high levels of saturated fat
* breast, ovarian, colon and prostate cancer
* fatty fish and fish oil
* colon, breast, lung, esophageal, skin and pancreatic cancers

what are proteins made up of?

carbon

hydrogen

oxygen

nitrogen

how much energy goes protein supply

4 kcal/gram

is protein stored?

no

what are the building blocks of proteins?

amino acids

what are amino acids made up of?

amino group

carboxyl (acid) group

hydrogen group

r group (side chain) - unique part!

how many essential amino acids are there?

9

what is transamination?

transfer of amine group from one molecule to another to create an amino acid

conditionally essential amino acid

body cannot synthesize enough during infancy, growth or disease and become required

what bond creates amino acids?

peptide bonds

what is denaturation?

causes a protein to unfold - ex. cooking an egg denatures the proteins that we eat (allowing us to eat it)

cause in AA shape…

causes a change in a protein shape

what are the functions of protein in the body?

hormones

growth/maintenance/repair

body structure and blood

fluid balance

transport

acid base balance

immune function

enzymes

fluid balance

proteins in the blood maintain optimal balance between fluids inside and outside cells and blood vessels (homeostasis)

what is albumin?

most abundant protein in the blood

* helps protein concentration of blood similar to that of cells

what is edema?

develops when blood albumin is low

low intake of protein =concentration to be out of balance and water moves into tissues

what is an acid-base balance?

maintenance of pH in body 7.35-7.45

antigens

foregin substances that enter our bodies and trigger an immune response

antibodies (secreted by white blood cells)

proteins produced by immune system in response to an antigen

enzymes

conduct specific chemical reactions

* speed up chemical reactions
* strings of 100-1000 of enzymes
* have a unique shape

deficiencies in enzymes

* inborn error in metabolism (inherited)
* can’t break down food into energy
* non-genetic causes
* illness, inadequate nutrition, medications

hormones

messengers that help regulate the various systems and functions of the body

made of lipids or proteins

sodium potassium pump

transport substances across cell walls

retinol binding protein

transporter of nutrients through bloodtream

proteins have water-repelling and water-attracting ends

allows for interaction with fat and water (lipoproteins)

energy (proteins)

energy is the least efficient function of proteins

* proteins are a last resources for energy

what does protien turnover include?

protein synthesis and protein breakdown