Chapter 6 Lipids

cholesterol

most well known sterol essential to health found in foods derived from animals (egg yolk, liver, meat, poultry, dairy products made from cream or whole milk are rich sources of the lipid)

embolus

- thrombus or part of plaque that breaks free and travels through blood stream - lodges in artery can create same serious consequences as stationary thrombus

The Dietary Guidelines for Americans (Acceptable Macronutrient Range - AMDR) recommends that adults should keep daily fat intake

between 20 and 35% of total calories

CVD

cardiovascular disease - heart disease, stroke, disease of blood vessels - 28% of deaths

Although considered the "silent disease," hypertension can increase the risk of ______.

heart failure stroke kidney disease

healthy arteries

smooth lining

lymphatic system

transports chylomicrons to thoracic duct where they enter bloodstream though left subclavian vein in chest

plant sterols and stanols

- structurally similar to cholesterol - lipids occur naturally in small amounts in grains fruits vegetables nuts seeds and legumes - compete with cholesterol for intestinal absorption - reduces amount of cholesterol absorbed - good to combats elevated blood cholesterol levels

thrombus

- when blood clots forms too easily - fixed bunch of clots that remain in place and disrupt blood flow - partially closes of artery's lumen

essential fatty acid

- linoleic acid and alpha-linolenic acid - body cannot synthesize these two essential fatty acids

which is easier to digest lipids or carbs

carbs because they are water soluble

omega-3 fatty acid

- PUFA (omega fat) - contains first c-c double bond at third carbon from omega end of the molecule

AI for alpha-linolenic acid

1.6 g/day for men and 1.1 g/day for women

AI for linolenic acid

17 g/day for men and 12 g/day for women

Which of the following tests should a doctor perform to determine a person's risk for developing atherosclerosis?

Check blood pressure Request lipoprotein profile Test triglyceride levels

lacteals

Chylomicrons are too large to be absorbed directly into the bloodstream and must pass through the larger openings of lacteals, which are lymphatic system vessels in each villus.

gallstones

Small crystals that form from bile in the gallbladder - main component is cholesterol

how are fatty acids transported through the bloodstream

as part of lipoproteins

what foods supply good sources of linoleic acid

pecans, almonds, avocado

bile salts

compounds in bile that aid in emulsification in the small intestine

CLA

conjugated linoleic acid

Compared to foods made with unprocessed plant oils, partially hydrogenated oils are less likely to go rancid because

contain fewer double bonds

tropical oils

contain more saturated than unsaturated fatty acids

fatty acids and cis fatty acids

most naturally occurring unsaturated fatty acids

fat malabsorption

poor absorption of fat soluble vitamins

steatorrhea

presence of lipid in stool - to prevent this and maximize fat absorption individual with missing or damaged gallbladder should eat smaller more frequent meals - avoid high fat meals

small intestine

primary site of lipid digestion and absorption

liver

produces bile

chylomicron

specific type of lipoprotein formed in enterocytes - transports the most triglycerides

gallbladder

stores bile

lipoproteins

water-soluble structures that transport lipids through the bloodstream

choline

water-soluble, vitamin-like compound; component of lecithin

sources of trans fat conjugated linoleic acid (CLA)

whole milk, butter, meat form grass-fed cows

high risk individuals of gallstones

women, over age 40, family history of gallstones, overweight, obese, those who lose weigh rapidly. American Indians and Mexican-Americans

low-density lipoprotein (LDL)

- VLDL becomes LDL - transports cholesterol and other lipids to tissues - cells remove LDL from bloodstream and use its lipids to make vital substances and structures - transports most cholesterol

what foods supply good sources of alpha linoleic acid

fatty fish, salmon, tuna

lipid storage diseases

genetic conditions that cause lipid accumulation in cells which damages tissues

end products of lipid digestion

glycerol, fatty acids, monoglycerides, cholesterol, and phospholipid fragments - later reassembled

pancrease

secretes lipase into small intestine to aid in digestion of fat

enterohepatic circulation

the process of recycling bile from the large intestine back to the liver to be reused during fat digestion 1. liver makes bile from cholesterol 2. stores bile until needed, then secretes bile into small intestine 3. duodenum receives bile from gallbladder, bile facilitates lipid digestion 4.ileum absorbs bile salts from bile, soluble fiber reduces absorption of bile salts 5. hepatic portal vein, bile salts return to liver bile salts absorbed in ileum of small intestine, bile salt travels through blood to liver, liver recycles used bile salts to make new bile - to reduce this soluble fiber

functions of lipids

- absorb fat soluble vitamins and phytochemicals - cushion body against bumps and blows - form/maintain cell membranes - participate in cell signaling - insulation - produce steroid hormones - provide and store energy (triglycerides) - enhance flavor, texture, and aroma of food

List the steps of dietary fat absorption from absorption in the small intestine and ending with entrance into the lymphatic system.

- absorption of glycerol, monoglycerides, and fatty acids into small intestinal cells - triglycerides are reassembled - triglycerides are packed into chylomicrons - chylomicrons enter lymphatic system

source of SFAs

- animal foods contain higher percentages of SFAs than most plant foods

gangrene

- artery to limb blocked tissue in extremity die

hypertension

- atheroscleosis contributes to hypertension - chronic condiiton - highe blood pressure even when person is relaxed - major risk factor in developing atherosclerosis and heart disease - work harder to circular blood through abnormally stiff arteries - elevated blood pressure can cause hardened arteries to tear/burst

lipases

- break down triglycerides and phospholipids - fat digesting enzymes because they can be absorbed

oxidation

- chemical process that alters compound's structure - saturated/trans fatty acids tend to go rancid because they are less likely to oxidizi

steps of atherosclerosis

- damage occurs in blood vessel lining - plaque deposited - plaque accumulates - pressure in artery increased - clot or spam in plaque clogged artery leads to heart attack

rich sources of lecithin

- egg yolks liver wheat germ peanut butter and soybeans - most abundant phospholipid in food - contains choline

source of MUFAs

- olive oil

high-density lipoprotein (HDL)

transports least triglycerides carries the most protein

functions of phospholipids in the body

needed for normal functioning of nerve cells aid in fat digestion and absorption form lipid bilayer of cell membranes

myocardial infraction

- heart attack - brain cells that are nourished by vessel die

fatty acids

- hydrocarbon chain - one end of the fatty acid has methyl group - other end is carboxylic acid

arterial plaques

- interferes with circulation because it narrows artery and block opening (lumen) - cause clots to form by roughening the smooth arterial surface and slowing blood flow. rupturing plaque causing a clot formation to repair rupture.

passages of fats in digestive system

- lipase in saliva mixes with food - food enters stomach - acidic stomach activates lipase - small intestine major site of digestion - fatty chime leaves stomach and enters small intestine simulates hormone secretion of CCK and secretin - secretin stimulates liver to produce bile and pancreas to secrete pancreatic juice to neutralize stomach acid - CCK signals pancreas to secrete digestive enzymes (pancreatic lipase) - CCK triggers gallbladder to release stores bile and sphincter that controls flow of bile and pancreatic juice and duodenum to opn

sources of polyunsaturated fats

corn oil and soybean oil

To meet the Dietary Guidelines for Americans recommendation for fat intake, an individual should ______.

emphasize foods such as fish, nuts, and vegetable oils balance intake of low-fat and high-fat foods

lipoprotein lipase

enzyme in walls of capillaries breaks down triglycerides in the chylomicron into fatty acids and glycerol

lipid digestion in small intestine

fatty chyme stimulates release of CCK, CCK signals pancreas to secrete digestive enzymes including pancreatic lipase, into duodenum, pancreatic lipase digests triglycerides and converts them into monoglycerides and 2 fatty acid molecules

According to the Dietary Guidelines, cholesterol intake should be ______.

limited

fat digestion occurs when

lipase breaks triglycerides down to monoglycerides bile from the gallbladder is present

production of bile via liver and storage of bile via gallbladder aids in what

lipid digestion by emulsifying lipids

triglyceride

lipid that has three fatty acids attached to three-carbon compound called glycerol

pancreatic phospholipase

removes fatty acid from second position of phospholipid molecule

pancreatic lipase

removes two fatty acids from each triglyceride molecule

The most common forms of cardiovascular disease in the US include ______.

stroke, heart disease

emulsifier

substance that keeps water-soluble and water-insoluble compounds mixed together

atherosclerosis

- lipid hardening - most cases of heart disease and stroke result from this - chronic process that affect artery function - caused by decreased aterial blood flow and arteriosclerosis - long-term disease process in which plaques build up inside the arterial walls - is a condition that can inhibit the blood flow and permanently damage the kidneys, eyes, legs, heart, and brain.

sterols

- lipid that have more chemically complex structure than triglyceride and phospholipid

triglycerides in foods

- mixture of unsaturated/saturated fatty acids - olive and cheeses - type of fatty acid (SFA, MUFA, and PUFA) often predominates

partial hydrogenation

- most of trans fat in processed food resulted from this - food manufacturing process that adds H atoms to some unsaturated fatty acids in liquid vegetable oil - converts cis to trans fatty acids - decrease rancidity (unappetizing odor and taste) - increase shelf life of a product - convert liquid oils to more solid fats

The major adverse health conditions associated with consuming high amounts of fat are _____.

- obesity - stroke - heart disease - certain cancers

PHOs

- partially hydrogenated oils - oils that contain these artificial fats - foods mad with PHOs can be stored for longer periods than foods that contain cis fatty acids because they have fewer double bonds

how does an emulsifier work?

- prevents fat from coalescing by using shell of water molecules - isolates individual fat droplets

arteriosclerosis

- reduced arterial wall flexibility - hardening of arteries - results from injury - ART IS SYMPTOM OF ATH - a loss of arterial flexibility or "hardening of the arteries"

classification of fatty acids

- saturated fatty acid - unsaturated fatty acid

classes of lipids

- triglycerides - phospholipids - sterols (ex. cholesterol)

ghee

- type of clarified butter - alternative to cooking oil - does not contain water or milk proteins - solid at room temp - higher smoke point

According to the Dietary Guidelines to reduce risk for cardiovascular disease, saturated fats should contribute

no more than 10% of total kilocalories.