FSHD Chapter 5
what is the difference between trans form and cis form in structure?
- cis form causes backbone of molecule to bend and hydrogen bonds are on the same side of the carbon - trans form has the hydrogen bonds on opposite sides
when are fatty acids used as the primary energy source by the muscles?
- during light activity - during rest
what are the advantages of using triglycerides to store energy in the body?
- energy dense - chemically stable - are space savers
what are the major functions of fatty acids and triglycerides in the body?
- energy storage - insulation - transportation of fat-soluble vitamins
what are symptoms of essential fatty acid defiency?
- flaky and itchy skin - diarrhea - wounds heal slowly - hair may fall out or lose pigment - growth restriction
what are the function of cholesterol?
- hormones : estrogen and testostrone - converted to bile - incorporated into cell membranes
Trans Fatty Acid Intake
- increases blood cholesterol - increases risk for Cardiovascular Disease - required to be on food labels (aim for 0g trans fat)
How to minimize intake of Trans Fat
- limit use of hydrogenated fats (margarines and shortening) - limit deep fried foods - limit high-fat baked goods - limit use of non-diary creamers (they replace milk fats with vegetables fats)
Which fatty acids are considered essential fatty acids?
- linoleic acid -alpha-linoleic acid
what are the positive attributes of dietary fat???
- many flavors are fat soluble, so fat enhances the flavor of foods - fat imparts a creamy texture to foods
what are the products of fat digestion?
- monoglycerides - fatty acids
Ways to raise HDL
- physical activity of at least 45min/day, 4 days a week - don't smoke - eat regularly - eat less total fat - moderate intake of alcohol
long chain fatty acids absorption
- reform into triglycerides - occurs in intestinal absorptive cells - not water soluble - enter the lymphatic system
Transportation of Dietary Fatty Acids
- reformed into triglycerides after absorption from small intestine - packing into chylomicrons - enter the lymphatic system and then bloodstream - lipoprotein lipase transports through blood
what has the biggest impact on blood cholesterol levels?
- saturated fat intake - trans fat intake
How to lower LDL
- see your doctor to assess other conditions - reduce dietary saturated fat and cholesterol - increase MUFA and PUFA - increase dietary fiber (soluble)
when is food considered low fat?
3 grams of fat or less per serving and, if the serving is 30 grams less or 2 tablespoons or less, per 50 grams of the food
what percent of total calories does the AHA recommend limiting transfat and saturated fat to?
5% - 6%
diglyceride
A breakdown product of a triglyceride consisting of two fatty acids bonded to a glycerol backbone
atherosclerosis
A buildup of fatty material (plaque) in the arteries, including those surrounding the heart.
alpha-linolenic acid
An essential omega-3 fatty acid with 18 carbons and 3 double bonds.
What are the 2 omega-3 fatty acids?
EPA and DHA
very-low-density lipoproteins
VLDL the lipoprotein created in the liver that carries cholesterol and lipids that have been taken up or newly synthesized by the liver
lipoprotein
a compound found in the bloodstream containing core of triglycerides and cholesterol surrounded by a shell of protein and phospholipids - serves as vehicles for transport of lipids from the small intestine and liver to the body tissues
emulsifiers
a compound that can suspend fat in water by isolating individual fat droplets, using a shell of water molecules or other substances to prevent the fat from coalescing - keeps mixtures of lipids and waters from separating
saturated fatty acid
a fatty acid containing no carbon-carbon double bonds - single bonds carbon-carbon bonds - mostly animal fats - solid at room temp
monounsaturated fatty acid
a fatty acid containing one carbon-carbon double bond - canola and olive oils - liquid at room temp
polyunsaturated fatty acid
a fatty acid containing two or more carbon-carbon double bonds - corn, soy bean, sunflower, and safflower oils - liquid at room temp
glycerol
a three- carbon alcohol used to form triglycerides
phospholipid
a type of lipid made of glycerol backbone, two fatty acids, and a phosphorus-containing group
AMDR
acceptable macronutrient distribution range
lipoprotein lipase
an enzyme attached to the cells that form the inner lining of blood vessels; it breaks down triglycerides into free fatty acids and glycerol
linoleic acid
an essential omega-6 fatty acid with 18 carbons and two double bonds
What food sources do we get saturated fatty acids?
animal fats
when is food considered to be reduced or less fat?
at least 25% less fat per serving than reference food
when is food considered to be reduced or less saturated fat?
at least 25% less saturated fat per serving than reference food
lipoprotein lipase breaks down triglycerides in the ____?
blood vessels
difference between the structure of the alpha-linolenic acid and linoleic acid?
both are polyunsaturated fatty acids but - alpha-linolenic acid has the first double bond of carbon on the 3rd carbon from the omega end (methyl group) - linoleic acid has the first double bond of carbon on the 6th carbon from the omega end (methyl group)
How can reduced fat change the foods?
can change texture or flavor
what is the leading cause of death in North American adults?
cardiovascular disease
what is elevated LDL strongly linked to?
cardiovascular disease risk - a build up of cholesterol in the blood vessels
LDL
carry cholesterol to cells - high levels in blood becomes plaque build up
what food sources do we get sterols>
cholesterol (animal foods only) eggs main dietary source
What are the roles of phospholipids and cholesterol in digestion and absorption?
cholesterol is a building block for bile acids - bile acids and phospholipids function as emulsifiers which help to break apart large droplets of fat into smaller droplets so that digestive enzymes
when is food considered to be saturated fat-free?
less than 0.5 gram of saturated fat per serving, and the level of trans fatty acids does not exceed 0.5 gram per servicing
which enzyme plays an important role in fat digestion?
lipase
what are oils at room temperature?
liquid
what are unsaturated fatty acids at room temperature?
liquid
fatty acids
long chains of carbons bonded together and flanked by hydrogens
what are examples of foods that are 40-60% as fat?
meats whole diary doughnuts
What are triglycerides broken down into?
monoglycerides fatty acids glycerol
Is there an RDA for fat?
no
are lean meats high in fat?
no
are phospholipids essential? why or why not?
no; because the body can create its own phospholipids
are sterols essential to the body? why or why not?
no; because the body can make it on its own
should we only consume high-fat foods?
no; we should balance some high-fat foods with low fat foods
what are examples of foods that are 80% as fat?
nuts bologna avocados bacon
which omega is in seafood?
omega 3
What are examples of foods that are 75% as fat?
peanut butter cheddar cheese
what makes up the structure of the lipid bilayer of cell membranes?
phopholipids
what food sources do we get unsaturated fatty acids?
plant oils
what type of oil do Dietary Guidelines recommend we use to prepare foods?
plant oils; to help decrease saturated fat intake (ex: lard, butter, etc)
HDl
synthesized by liver and intestine - high proportion of protein - picks up cholesterol from dying cells and other sources - transfer cholesterol to other lipoproteins and back to the liver
how is fat carried in the bloodstream?
taken in lipoproteins - chylomicrons - VLDL - LDL - HDL
triglyceride
the major form of lipid in the body and in food - composed of three fatty acids attached to a glycerol
monounsaturated, saturated, and polyunsaturated fats all provide the same number of calories: true or fasle?
true
To reduce heart attack risk, the American Heart Association (AHA) recommends eating fish how often?
twice a wekk
Types of fat
unsaturated, saturated, trans fat
can the body make chloesterol?
yes
is sirloin meat lean?
yes
short and medium chain fatty acid absorption
(< 12 carbons) - water soluble - diffusion - enter the portal vein system
VLDL absorption
*are high in triglycerides - once broken down the glycerol and fatty acids available and primary cholesterol is left - becomes LDLs
Benefits of a high HDL level
- Removes cholesterol from the bloodstream - HDL may block oxidation of LDL - Reduces risk of cardiovascular disease - Pre-menopausal women have higher HDL
Process of digestion of fats
- begins in stomach - gastric lipase acts on triglycerides, and short/medium chain fatty acids (<12 carbon chain) - minimal digestion occurs in stomach - then it goes to the small intestine which is the primary site of fat digestion - pancreatic lipase is released from pancreas and digests most triglycerides - bile is released to emulsify fat in water digestive juices - fat is broken down into monoglycerides and fatty acids
what is the process of making hydrogenated oil?
- take unsaturated vegetable oil and add hydrogen under pressure - created partially hydrogenated fat (semisolid)
which fatty acids are packaged into chylomicrons?
- triglycerides (85%) - phospholipids (6-12%) - cholesterol (1-3%) - protein (1-2%)
transportation of synthesized lipids
-made primarily by the liver -transport lipids from liver to the body - density = protein content
when is food considered low saturated fat?
1 gram of saturated fat or less per serving and not more than 15% of calories form saturated fatty acids
what amount of plant oil is good to maintain health?
2-4 tsp of plant oil
What is AMDR set by the Food and Nutrition Board for Lipids?
20% - 35%
What are the Dietary Guidelines for fat?
20-35% of total kcal from fat - < 10% of saturated fat - < 1% of trans fat - no limit for cholesterol
High-density lipoprotein
HDL The lipoprotein in the blood that picks up cholesterol from dying cells and other sources and transfers it to the other lipoproteins in the bloodstream or directly to the liver aka good cholesterol.
what does the layer of triglycerides beneath the skin do?
insulate the body
low-density lipoprotein
LDL the lipoprotein in the blood containing primarily cholesterol - role is to transport cholesterol to tissues - provides some of the building blocks necessary for cell growth and development (ex: synthesis of cell membranes and hormones) - may cause atherosclerosis aka bad cholesterol
hydrogenation of fatty acids
Process used to solidify an oil Addition of H to C=C double bonds Increases shelf life Formation of trans fatty acid (similar to shape of saturated fatty acid)
does HDL increase or decrease cholesterol level?
decrease
what are higher HDL levels associated with?
decreased risk for cardiovascular disease
What food sources do we get phopholipids?
egg yolk peanuts soy beans organ meat
what is the most common source of lecithin?
eggs
what are phospholipids often used as in foods?
emulsifiers
what deficiency would you suspect if a person has flaky and itchy skin, diarrhea, and poor wound healing with infection?
essential fatty acids either linoleic acid or alpha-linoleic acid
hidden fat ingredients
fat lard nut oils butter cream egg mayonnaise partially hydrogenated oils
when is a food considered fat free?
if it has less than 0.5 grams of fat per serving
methyl group (omega end)
in chemistry, a carbon atom that shares bonds with three hydrogen atoms
acid group (alpha end)
in chemistry, a functional group that consists of a carbon atom that shares bonds with two oxygen atoms - the site where fatty acids are linked to glycerol to form triglycerides
does LDL increase or decrease cholesterol?
increase
the presence of fat in foods ______ the absorption of fat-soluble vitamins from the small intestine
increases
what are examples of foods that are 100% fat?
salad oils butter maragrine mayonnaise
functions of fat in food
satiety, flavor, texture
saturated fatty acids vs unsaturated fatty acids
saturated: single carbon-carbon bonds unsaturated: double carbon-carbon bonds
what are fats at room temperature?
solid
what are saturated fatty acids at room temperature?
solid
what food sources are cholesterol found in?
sources of animal origin
what 3 organs/glands produce lipase?
stomach salivary glands pancreas
where are triglycerides broken down?
the small intestine
what are the latest guidelines from the Dietary Guidelines and AHA about dietary cholesterol intake?
there are none because it has little impact on blood cholesterol levels
what property do all types of lipid have in common?
they do not readily dissolve in water
in what form does the body mainly store energy?
triglycerides
What are the 3 classes of lipids?
triglycerides (fat), phospholipids (lecithin), sterols (cholesterol)