NTR Chapter 5: Lipids: Fats, Phospholipids, and Sterols
What happens when the chylomicrons enter the blood?
delivers triglycerides to body cells-first broken down to glycerol and fatty acids; fatty acids are either used to provide energy or turned back into triglycerides for storage.
chylomicron
a lipoprotein that transports lipids from the mucosal cells of the small intestine and delivers triglycerides to other body cells.
fatty acids
a molecule made up of chains of carbons linked to hydrogens, with an acid group at end of chain.
micelles
a particle that is formed in the small intestine when the products of fat digestion are surrounded by bile acids. It facilitates the absorption of lipids.
lipoprotein
a particle that transports lipids into the blood.
hydrogenation
a process used to make partially hydrogenated oils in which hydrogen atoms are added to the carbon-carbon double bonds of unsaturated fatty acids, making them more saturated. Trans fatty acids are formed during this process.
cholesterol
a sterol, produced by the liver and consumed in the diet, which is needed to build cell membranes and make hormones and other essential molecules.
phospholipids
a type of lipid whose structure includes a phosphorus atom.
sterol
a type of lipid with a structure composed of multiple chemical rings.
What is the function of phospholipids?
allows water and fat to mix, synthesizes the neurotransmitter acetylcholine, which activates the muscles and plays and important role in memory.
where can you find saturated fatty acids?
animal foods (most), and plants.
adipose tissue
body fat that lies under the skin and around internal organs
What are the risk factors for heart disease?
diabetes High BP obesity high blood cholesterol genetics lifestyle: smoking, exercise, and diet.
tropical oils
exception to plant oils being low in unsaturated fatty acids-includes palm oil, kernel oil, and coconut oil. Found in plants that are common in tropical climates
What must be processed further before going into the blood?
fatty acids, cholesterol, and other fat-soluble substances.
polyunsaturated fatty acid
contains more than one carbon-carbon double bond.
monounsaturated fatty acid
contains one carbon-carbon double bond. Ex.: canola, olive, and peanut oils, as well as nuts and avacados
What are some good food choices that decreases the risk of heart disease?
fish: high in omega-3 fatty acids nuts: high in monounsaturated fatty acids oatmeal: good source of soluble fiber soy: high in polyunsaturated fatty acids fruits vegetables: high in antioxidants
What is the function of omega-6 and omega-3 fatty acids?
formation of phospholipids that give cell membranes their structure and functional properties, essential for growth, development, and fertility, as well as more maintaining the structure of red blood cells in the skin and nervous system.
What decreases the risk of cancer?
fruits and vegetables- high in antioxidants fish (high in omega-3 fatty acids)
atherosclerosis
hardening of the arteries-building up of fatty materials in the walls of the arteries.
Where is cholesterol found?
only in animals
What kind of sterols do plants have?
plant sterols-helps form plant cell membranes. Helps reduce cholesterol levels in the body.
functions of triglycerides in adipose tissue?
provides light-weight energy storage molecule, cushions our internal organs, insulates us from changes in our temperature; triglycerides in oils: lubricate body surfaces, keeping the skin soft and supple.
Which fatty acid is solid at room temperature?
saturated fatty acids-found in beef, butter, and lard-increases risk of heart disease
Cancer
second-leading cause of death risk can be reduced with changes in the diet
Digestion of Lipids
start in the stomach (gastric lipase), liver produces bile (aides in the digestion), pancreatic lipase breaks down triglycerides into monoglycerides, formation of micelles in the small intestine, inside mucosal cells monoglycerides are reassembled into triglycerides and enters the lymph to be transported to the blood
lipids
substances that do not dissolve in water
feasting
when excess energy is consumed, it is stored as triglycerides in adipose tissue
fasting
when no food has been eaten for a while, triglycerides from adipose tissue are broken down, releasing fatty acids as an energy source.
omega-6 polyunsaturated fatty acid
when the first double bond occurs between the sixth and seventh carbon atoms (from omega end)-corn oil, safflower oil, soybean oil, and nuts
What is HDL cholesterol referred to as?
"good cholesterol"- high levels in the blood is associated with a reduction in the risk of heart disease.
phospholipid structure
2 fatty acids, 1 glycerol, and 1 phosphate group.
triglyceride structure
3 fatty acids and 1 glycerol
Why do food manufacturers add hydrogenated oils too foods?
Because they are more solid at room temperature, they can be stored longer without becoming rancid.
Why has the use of partially hydrogenated oils in the food industry been declining?
Consumption of synthetic trans fat increases risk of heart disease-FDA has been ruling the use of this unsafe use for food.
What in your diet decreases the risk of heart disease?
High fiber diets Consuming: fish, nuts, whole grains, fruits, and vegetables.
What in your diet increases the risk of heart disease?
High sodium saturated fat trans fat high red meat intake
Factors for heart disease with age
Men: >45 Women: >55
What happens after the micelles have been used?
The bile acids in the micelles are also absorbed and returned to the liver to be reused.
low-density lipoproteins
a lipoprotein that transports cholesterol to cells; contains higher portion of cholesterol than do chylomicrons or VLDL's.
essential fatty acid defiency
a condition characterized by dry, scaly skin and poor growth that results when the diet does not supply sufficient amounts of linoleic acid and alpha-linoleic acid.
saturated fatty acid
a fatty acid in which the carbon atoms are bonded to as many hydrogen atoms as possible; therefore contains no carbon-carbon double bonds.
unsaturated fatty acids
a fatty acid that contains one or more carbon-carbon double bonds; maybe either monounsaturated or polyunsaturated.
essential fatty acids
a fatty acid that must be consumed in the diet because it cannot be made by the body or cannot be made in sufficient quantities to meet the body's needs.
monoglyceride
a glycerol molecule with one fatty acid attached.
high-density lipoprotein (HDL)
a lipoprotein that picks up cholesterol from the cells and transports it to the liver so that it can be eliminated from the body.
What increases the risk of cancer?
high fats diet trans fatty acids-breast cancer
What kind of diets reduces blood cholesterol levels?
high-fiber diets
omega-3 polyunsaturated fatty acid
if the first double bond occurs between the third and fourth carbon atoms (from the omega end)-flaxseed, canola oil, and nuts, fish oild
What happens when the body absorbs lipids?
in the small intestine, bile acids in bile act as emulsifiers, and breaks down large lipid droplets into small globules. The triglycerides in the globules can then be digested by enzymes from the pancreas.
What do high levels of LDL's create?
increased risk of heart disease- referred to as "bad cholesterol"
What are considered "essential fatty acids?"
linoleic acid (omega-6), and alpha-linolenic acid (omega-3)
very-low density lipoproteins or VLDL's
lipoproteins that circulate the blood, and delivers triglycerides to body cells-once triglycerides are removed, a small particle remains. two-thirds are returned to the liver, and the rest is transformed in to low-density lipoproteins or LDL's.
Where do the chylomicrons pass through to get into the blood?
lymph-too large to enter the capillaries in the small intestine.
What gender is more susceptible for having a heart disease at an early age?
men
What is cholesterol needed for?
synthesizing other sterols, including vitamin D; bile acids, which are emulsifiers in bile; cortisol, which is a hormone that regulates our physiological response to stress; and testosterone and estrogen, which are hormones important for reproduction.
triglyceride
the major type of lipid in the food and the body; consisting of three fatty acids attached to glycerol molecule
What is fiber's function in the body?
traps the bile in the small intestine and does not allow bile to be to reabsorbed or recycled. Liver is then forced to pull cholesterol from the blood to make new bile- which lowers the blood cholesterol
Which fatty acid is liquid at room temperature?
unsaturated fatty acids-bent chains (corn, safflower, and sunflower oils), lowers risk of heart disease
Which fatty acid is susceptible to rancidity?
unsaturated fatty acids-easily damaged by oxygen
