diet and nutrition chapter 6 lipids

monounsaturated fatty acid

has only one double bond linking two carbon atoms;

c reactive protein

he development of CVD involves chronic inflammation.34 The liver responds to infection and inflammation by producing and releasing high-sensitivity C-reactive protein (hs-CRP), simply referred to as C-reactive protein or CRP, into the bloodstream. People with elevated CRP are more likely to develop CVD and hypertension than people who have lower levels of the protein.35 Thus, elevated CRP may be a biomarker for atherosclerosis

high density lipoprotein

transports chlesterol away from tissues and to the liver where it can eliminated

lipid digestion

As the food enters the stomach, the organ's acidic environment activates the lipase, enabling some lipid breakdown to occur. The small intestine, however, is the primary site of lipid digestion. As the fatty chyme leaves the stomach and enters the small intestine, it stimulates certain intestinal cells to secrete the hormones cholecystokinin (kol'-e-sis'-toe-kye'-nin) (CCK) and secretin. Secretin stimulates the liver to produce bile and causes the pancreas to secrete bicarbonate-rich pancreatic juice, which is necessary to create an alkaline environment in the small intestine. CCK signals the pancreas to secrete digestive enzymes, including pancreatic lipase, into the duodenum of the small intestine. CCK also triggers the gallbladder to release stored bile and the sphincter that controls the flow of bile and pancreatic juice into the duodenum to open.

hydrogenation

Partial hydrogenation is a food manufacturing process that adds hydrogen atoms to some unsaturated fatty acids in liquid vegetable oil, which results in the formation of SFAs. Foods made with partially hydrogenated fat can be stored for longer periods of time—for some products, over a year—than foods that contain cis fatty acids. The reason is that trans fatty acids are less likely to undergo oxidation, a chemical process that alters the compound's structure. in the body, trans fatty acids raise "bad" blood cholesterol levels and lower "good" blood cholesterol levels, which may increase the risk of heart disease

lipid apsorption

The majority of lipid absorption occurs in the small intestine, particularly in the duodenum and jejunum. Glycerol, fatty acids, monoglycerides, cholesterol, and phospholipid fragments are the end products of lipid digestion.

dietary fat recommendations

Total fat 20-35% of total calories (45-75 g total fat for a 2000-kcal diet) Saturated fat Less than 10% of total calories (22 g saturated fat for a 2000-kcal diet) Linoleic acid 5-10% of total calories (11-22 g linoleic acid for a 2000-kcal diet) Alpha-linolenic acid 0.6-1.2% of total calories (1-3 g alpha-linolenic acid for a 2000-kcal diet) Cholesterol As little as possible while consuming a healthy diet Trans fat Keep intake as low as possible

trans fat

Trans fats are unsaturated fatty acids that have at least one trans double bond in opposite sides. Processed foods and margarines contribute the largest share of trans fatty acids in the American diet.

hydrocarbon chain

a chain of carbon atoms bonded to each other and to hydrogen atoms.

triglyceride

a lipid that has 3 fatty acid attched to a 3 carbon compund gycerol

emulsifier

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

sterols

are lipids that have a more chemically complex structure than a triglyceride or phospholipid.

chylomicrion

chylomicron (ky'-low-my'-kron) is a specific type of lipoprotein formed in enterocytes.

arteriosclerosis

condition that results from atherosclerosis and is characterized by loss of arterial flexibility

saturated fatty acid

each carbon within the chain is saturated, that is, completely filled with hydrogen atoms.

lipases

enzymes that break down lipids.

LIPIDS

include triglycerides (try-glis'-er-eyeds), phospholipids (fos-foe-lip'-ids), and sterols, such as cholesterol. Lipids dissolve in organic solvents such as alcohol and acetone, but most lipids are insoluble( do not desolve in water) in water. oil is less dense than water

cholesterol

lipid found in animal foods percursor for steroid hormones bile and vitamin d Cholesterol, however, is essential to health as it is an integral component of every cell membrane in the body. Although cholesterol is not metabolized for energy, cells use it to synthesize a variety of substances, including steroid hormones, such as vitamin D, cortisol, aldosterone, testosterone, estrogen, and progesterone

monoglyceride

lipid that has one fatty acid attched to a 3 carbon compound one fatty acid + gycerol

lipoprotein

lipoprotein lipase (LPL), an enzyme in the walls of capillaries, breaks down their load of triglycerides into fatty acids and glycerol.

very low density lipo protein (VLDL)

lipoprotein made in the liver that carries much of the triglycerides in the blood stream

arthersclerosis

long-term disease process in which plaque builds up inside arterial walls

Major functions of lipids

the body uses fats and other lipids to: Provide and store energy (triglycerides) Form and maintain cell membranes Produce steroid hormones Insulate the body against cold temperatures Cushion the body against bumps and blows Form body contours Absorb fat-soluble vitamins and phytochemicals

prostaglandins

produce a variety of important effects on the body, such as stimulating uterine contractions, regulating blood pressure, and mediating the immune system's inflammatory response.

lipid digestion and absoption

1. only minor digestion of fat takes place in the stomach 2. the liver produces bile which is stored in the gallbladder and released through the bile duct in to the small intestine. bile aid in lipid digestion and absorption by emulsifying lipids in digestive juices. 3. the pancreas secrets a mixture of enzymes including lipase in to the small intestine 4. the small intestine is the primary site for digestion and absorption of lipids once absorbed long chain fatty acids are packaged for transport through the lymph and blood stream 5 less than 5% of undigested fat is excreted in feces

diglyceride

2 fatty acids +gycerol

polyunsaturated

2 or more double bonds

gycerol

3 carbon alcohol the back bone of fatty acid

triglyceride

3 fatty acids +gycerol 95% of lipids in food and body

LOW DENSITY LIPOPROTEIN (LDL)

carries cholesterol into tissues, linked to increased risk of cardio vascular disease

Cardiovascular disease

group of diseases that affect the heart and blood vessels; includes coronary artery disease, stroke, and disease of the blood vessels

eicosanoids

group of long fatty chains with hormone like functions the body needs AA, EPA, and DHA to make eicosanoids.

unsaturated fatty acid

has at least two neighboring carbons within the chain that are missing two hydrogen atoms, and a double bond holds the two particular carbons together

fatty acids

hydrocarbon chain found in lipids. one end of the chain forms a carboxylic acid and the other end a methyl group ( the omega end) short-chain fatty acids have 2 to 4 carbons; medium-chain fatty acids have 6 to 12 carbons; and long-chain fatty acids have 14 to 24 carbons. Chemists identify a fatty acid by (1) its number of carbon atoms and (2) the type of bond between carbon atoms in the hydrocarbon chain. These two characteristics influence how fatty acids can affect health.

lipoproteins

Lipoproteins are water-soluble structures that transport lipids through the bloodstream

phospholipids

type of lipid needed to make cell membranes and for proper functioning of nerve cells. chemically similar to a triglyceride, except that one of the fatty acids is replaced by a chemical group that contains phosphorus and, often, nitrogen Phospholipids are naturally found in foods derived from plants and animals. Phospholipids have hydrophilic and hydrophobic portions. Unlike triglycerides, phospholipids are partially water soluble because the phosphorus-containing portion of the molecule is hydrophilic (hydro = water; philic = loving); that is, it attracts water A phospholipid molecule also has a hydrophobic (phobic = fearing) portion that avoids watery substances. As a result, a phospholipid can serve as an emulsifier. molecule that attracts water phosphate molecule that avoids water and attracts lipids is the fatty acid. Phospholipid deficiencies among adults are uncommon, because these lipids occur in a variety of foods and healthy adults synthesize these compounds. Egg yolks, liver, wheat germ, peanut butter, and soybeans are rich sources of lecithin (less'-eh-thin), the most abundant phospholipid in food. Lecithin contains choline (co'-leen), a water-soluble, vitamin-like compound that has many functions. Nerves, for example, use choline to form the neurotransmitter acetylcholine (ah-see'-till-co'-leen). A neurotransmitter is a chemical that transmits messages between the nerve cells