chapter 5 notes

trends in fat intake

- 1950s --> 1996 - americans made changes in food choices with the goal to decrease fat intake - number of kcal we eat increased and number of grams to drop from 37% in 1971 to ~34% today. but overall calorie intake is higher causing an obesity epidemic.

translating recommendations in healthy diets

- Calculating percent of energy from fat: Fat provides 9 kcal/g, Multiply grams of fat by 9 kcal/g, Energy kcal from fat = grams fat x 9kcal/g fat, Calculate % energy from fat, % of energy from fat = kcal from fat/total kcal x 100 - using exchange lists to estimate fat content - how to choose fat and cholesterol: limit your intake of cholesterol, trans fat and saturated fat, increase the proportion of polyunsaturated and monounsaturated fats, up you omega-3 intake including flax seeds, fish, leafy green vegetables, and walnuts

using food labels to make healthy choices

- Fat free: contains less than 0.5 g of fat per serving - Low fat: contains less than 3 g or less of fat per serving - Reduced: contains at least 25% less fat per serving than original product. - Saturated fat free: contains less tan 0.5 g of saturated fat per serving - Cholesterol free: contains less than 2 mg of cholesterol - Low cholesterol: contains 20 mg or less of cholesterol - Lean: contains less than 10 g of fat - Extra lean: contains less than 5 g of fat

using MyPlate to make healthy choices

- Generally, grains, fruits, and vegetables are low in total fat and saturated fat, and they contain no cholesterol However, choices form these groups need to be made with care to avoid fats that are added in processing or preparation - Smart choices from the protein and dairy groups can reduce your intake of unhealthy fats and boost healthy ones. - Choosing legumes as protein will add fiber without adding total fat, saturated fat, or cholesterol, choosing nuts and seeds. - Limiting oils, butter, margarine, fatty sauces, and salad dressings used in cooking.

fat and cholesterol recommendations:

- Infants: need a diet with 40-55% of energy as fat to get enough calories - Children and adolescents: Because children and teens need more total fat in their diets to meet their needs for growth, the AMDRs for fat are higher for these groups: 30-40% of energy for ages 1-3 years, and 25-35% of energy for ages 4-18 years. These amounts meet the needs for growth and are unlikely to increase the risk of chronic disease. - Adults and Older Adults: recommendations for lipid intake are the same for older and younger adults. Fat intake must be carefully balanced with other nutrients in the elderly to reduce the risk of malnutrition. - Pregnancy and Lactation: the AMDRs for fat intake are not increased during pregnancy or lactation, but the AIs for essential fatty acids are slightly higher than those for nonpregnant women.

an egg a day

- Majority of epidemiological studies have no relationship between dietary cholesterol or egg consumption and CVD - Eggs are low in saturated fat - Eggs are good sources of zinc, B vitamins, Vitamin A, and iron - Dietary guidelines concluded: eating one egg per day is not harmful and doesn't increase risk of CVD

triglyceride energy production

- Only glucose catabolism can proceed without enough oxygen. - During high intensity exercise is main time when anaerobic metabolism of glucose occurs - Catabolism of fatty acids requires presence of adequate oxygen and is called aerobic. 1. Fatty acids are broken down into acetyl CoA when needed as a source of energy. - Fat catabolism (oxidation) produces a lot more ATP than glucose catabolism (predictable based on 9kcal/g vs. 3 kcal/g) this is based on more carbons. - Fatty acids are transported inside mitochondria. - Beta oxidation splits the C chain into 2 C-C units that form acetyl CoA and high-energy electrons 2. Acetyl CoA combines with oxaloacetate to enter the citric acid cycle - Citric acid cycle produces 2 molecules of CO2 and releases high energy electrons that are shuttled to the electron transport chain 3. Energy from the high-energy electrons released from beta-oxidation and the TCA cycle pumps hydrogen ions across the inner mitochondrial membrane - As the hydrogen ions flow back, the energy is used to convert ADP to ATP. The electron are combined with oxygen and hydrogen to form water 4. Glycerol molecules, from triglyceride breakdown, contain 3 carbon atoms. These carbons can be used to produce small amounts of ATP or form glucose.

lipoproteins

- are created by combining water-insoluble lipids, phospholipids, and protein. - help transport triglycerides, cholesterol, and fat-soluble vitamins from the small intestine (chylomicrons) and stored lipids from the liver (VLDL and LDL) - remember that short and medium chain fatty acids are absorbed into the portal blood then go to the liver and liver released them into the blood to circulate to cells of the body.

Eicosanoid synthesis and function

- The American Diet has too few omega-3 fatty acids - getting enough essential fatty acids in your diet will prevent deficiency, but the ratio of dietary omega-6 to omega-3 fatty acids also affect your health. - eicosanoids help regulate blood clotting, blood pressure, immune function, an other body processes. The effect an eicosanoid has on these functions depends on the fatty acid from which it is made. - since inflammation play a role in the progression of heart disease; a nutrient with anti-inflammatory properties would protect against heart disease. The anti-inflammatory properties of omega-3 fatty acids have also been shown to be of benefit in other chronic disease that involve inflammatory processes such as rheumatoid arthritis, inflammatory bowel disorders, and cancer

sterols: cholesterol

- a compound of great importance: structural component of cell membranes part of myelin precursor of sex hormones and vitamin D needed to synthesize cholic acid - cholesterol is necessary in the body but not an essential nutrient because the liver and other tissues can synthesize it - egg yolks and organ meat such a liver and kidneys are high in cholesterol - lean red meats and skinless chicken are low in total fat but still contain some cholesterol - cholesterol is NOT found in plants

sterols

- a type of lipid found in plants and animals. - do not dissolve in water. Their structure consists of multiple chemical rings. - cholesterol is a type of sterol found only in animals. (diets high in cholesterol can increase their risk of heart disease, more than 90% of cholesterol in the body is found in cell membranes) - plant sterols can help reduce cholesterol in the body. - soluble fibers (cholesterol lowering effects)and plant sterol and stannous (reduced risk of heart disease) can be part of health claims on food labels. - dietary guidelines for Americans and Daily value on food labels have a limit of no more then 300 mg of cholesterol per day. - however, some argue that this should only be for individuals who do not decrease cholesterol synthesis when they consume dietary cholesterol.

heart disease risk factors:

- age: increased risk in men age 45 and older and in women age 55 and older - gender: men an women are both at risk for heart disease but men are generally affected a decade earlier than women. the difference is due in part to the protective effect of the hormone estrogen in women. - genetic background: African americans have a higher risk of heart disease than the general population, in part due to their higher incidence of high blood pressure. Mexican Americans, native Americans, and Hawaiians have higher risk, due in part to higher incidence. - high blood pressure: can damage blood vessel walls, contributing to atherosclerosis. Forces the heart to work harder causing it to enlarge and weaken over time. - diabetes: high blood glucose damages blood vessel walls. - obesity: obesity increases blood pressure, blood cholesterol levels, and the risk of developing diabetes.

trans fatty acids

- an unsaturated fatty acid in which the hydrogen atoms are on opposite sides of the double bond. - trans fatty acids are found in small amounts in nature (dairy and maybe meat) , but most of the transfers we eat come from products that have undergone hydrogenation or processing. - hydrogenation causes one double bond to become saturated. - trans fatty acids have been show to raise blood cholesterol levels and increase the risk of heart disease; and may be worse than saturated fatty acids. - info about trans fats is included on food labels. - trans fatty acid is an unsaturated fatty acid, but has the spatial shape and actions of a saturated fatty acid. - partial hydrogenation causes most or many double bonds to become saturated, but some develop transfiguration - complete hydrogenation means that all the carbon-carbon double bonds are gone. the carbons now have single bonds with hydrogen. - while many manufacturers have reformulated to reduce trans fatty acids , trans fatty acids may still be in the margarines, vegetable shortening, and shelf-stable baked goods. - Cis fatty acid has each hydrogen on the same side which produces a "kink" in the molecule.

very low density lipoproteins

- are smaller than chylomicrons but still contain a high proportion of triglycerides - the liver is the major lipid-producing organ in the body. - triglycerides/lipids produced in the liver are incorporated into entities called VLDLs

how cholesterol is eliminated

- because most body cells have no system for breaking down cholesterol, it must returned to the liver to be eliminated from the body. this reverse cholesterol transport is accomplished by the densest of the lipoprotein particles, called HDLs. - these particles originate form the intestinal tract and liver and circulate in the blood, picking up cholesterol from other lipoproteins and body cells - they function as a temporary storage site for lipids. Some of the cholesterol in HDLs is taken directly to the liver for disposal and she is trasnferred to organ that have a high requirement for cholesterol, such as those involved in steroid hormone synthesis. - high levels of HDL in the blood help prevent cholesterol from depositing in the artery walls and are associated with a reduction in heart disease risk.

changes in fat and energy intake

- between 1970 and today, the average man increased his kilocalorie intake by 168 and the average woman increased her kilocalorie intake by 335 kcal per day. - most of the increase in kilocalories was due to greater consumption of carbohydrates. - while percentage of kilocalories from fat decrease in the diet, the grams of fat consumed changed very little. - more pizza, french fries, high fat snacks, mac and cheese, cheeseburgers, and burritos - larger portion sizes - more "away from home" prepared foods.

dietary fat and cancer

- cancer is the second leading cause of death in the United States. Can be reduced with changes in the diet and activity patterns. Populations consuming diets high in fruits and vegetables tend to have a lower cancer risk.

lipid function in the body: 2. lipids regulate body processes

- cholesterol and fatty acids are both used to synthesize regulatory molecules in the body. cholesterol is used to make steroid hormones (sex hormones and stress hormones) - essential polyunsaturated fatty acids: Linoleum acids and alpha-linoleic acid are used to make hormone-like regulation molecules (blood pressure, blood clotting, immune function) - essential fatty acids are important for: formation of the phospholipids the give cell membranes their structure and functional properties; growth, development, fertility, maintaining structure of red blood cells and cells in the skin and nervous system; brain development in infants and young children; regulators of glucose and fatty acid metabolism through their role in gene expression.

dietary factors that may help reduce the risk of heart disease

- consuming omega-3 and omega-6 polyunsaturated ; lowers LDL cholesterol, more omega-3 reduces blood clotting - consuming plants foods including fruit and vegetables, whole grains, and legume (fiber, vitamins, minerals, and phytochemical [antioxidants]) - soluble fibers reduce blood cholesterol

low density lipoproteins

- contain a higher proportion of cholesterol than do other lipoproteins - approximately 2/3 of LDLs return to the liver; the remainder are transformed in the blood into LDLs - LDLs contain less triglyceride and more cholesterol and VLDLs. LDL deliver cholesterol to the cells. - if the amount of LDL cholesterol in the blood exceeds the amount that can be used by the cells, the result is a high level of LDLs. High levels of serum LDLs have been associated with an increased risk for heart disease.

saturated fatty acids

- contain carbons in a chain that are each bound to two hydrogens. - all carbons are completely surrounded by hydrogen (only single bonds) - most animal fats and tropical oils contain saturated fatty acids. - diets high in saturated fatty acids have been shown to increase the risk of heart disease - oxygen damage is rancidity. - 2 examples of animal sources of saturated fatty acids: Palmitic acid (16C) and stearic acid (18C) - 2 examples of plant sources of saturated fatty acids: palm oil, palm kernel out, coconut oil. these are often called tropical oils because they are found in plants common in tropical climates. - roast beef, butter, cheddar cheese, milk, chocolate, coconut oil.

monounsaturated:

- contain one carbon-carbon double bond. - canola, olive, peanut oils, as well as nuts and avocados are high in monounsaturated fatty acids such as oleic acid.

phospholipids

- contain two fatty acids (lipids) + a phosphate group attached to a variety of other molecules. - have a water-loving and fat-loving part. - very important in cell membranes and as transport molecules. - phosphoglycerides such as lectin, are the major class of phospholipids. they can act as emulsifiers because it is soluble in both water and fat. - ex: egg yolks contain phospholipids and serve as an emulsifier in cake batter allowing water and oil to mix and stay together. - phosphoglycerides form a lipid bilayer in cell membranes helping to regulate what can pass in and out of the cell. the specific functions depend on the molecule that is attached to the phosphate group.

how fat is stored and retrieved: fat storage - feasting or "fed" state

- excess energy = fat storage in adipose tissue - packaged in chylomicrons - transported directly from intestines to adipose tissue - limitless storage

lipids are the chemical term for fat. they are groups of organic molecules, most of which do not dissolve in water:

- fatty acids and triglycerides - phospholipids - sterols

cardiovascular disease: inflammation

- first there is an initial injury. injury attracts monocytes. monocytes allow LDL particles to pass into the arterial wall. - once inside the wall, LDL is modified. oxidized LDL which is pro-inflammatory. - oxidize LDL attracts more monocytes, promotes differentiation of monocytes to macrophages, promotes macrophages to take up the oxidized LS --> foam cells - foam cells eventually burst causing fatty steaks on walls of arteries. - accumulation of cholesterol and proteins form plaque. inflammation continues and plaque builds up. Arteries narrow and lose its elasticity. Prices continues and fibrous cap of smooth muscle cells and fibrous proteins form over the plaque. - cap is like a scab on a cut but can rupture. ruptured caps can lead to blood clots. Blood clots can block artery where they originate or travel and block artery elsewhere.

lipoproteins: chylomicrons

- formed in the mucosal cells of the small intestine - a combination of diet-derived triglycerides, cholesterol, and phospholipids and a small amount of proteins - helps to transport long chain fatty acids, dietary cholesterol, and fat-soluble vitamins into the lymphatic system and into the blood stream without passing through the liver - deliver triglycerides into the body's cells

high density lipoproteins

- high in cholesterol and are the densest lipoproteins due to their high protein content. - most cells cannot break down cholesterol - HDLs pick up cholesterol from the cells and return it to the liver for reuse or elimination in the bile. - HDLs are formed by the liver and the intestines - high levels of HDL in the blood help precent cholesterol from depositing in the artery walls - high levels of HDL are associated with a reduction in heart disease risk.

lipid transport

- how lipids are absorbed and transported through the body depend on their solubility in water. - short and medium chain triglycerides are water soluble. they are easily digested and the resulting short and medium chain length fatty acids don't require micelles to be absorbed. Once absorbed, they pass directly into the blood and travel to the liver and other cells throughout the body. - lipids that are not soluble in water, such as long chain fatty acids, cholesterol, and fat-soluble vitamins cannot enter the bloodstream directly so they must be packaged for transport They are covered in a water-soluble envelope of proteins, phospholipids, cholesterol to form lipoproteins. - long chain fatty acids and cholesterol cannot enter the blood stream directly but must be incorporated into lipoproteins called chylomicrons different types of lipoproteins transport dietary lipids from the small intestine to body cells, from the liver to body cells , and from body cells back to the liver for disposal.

essential fatty acid deficiency

- if adequate amounts of fatty acids are not consumed, a deficiency can result. - symptoms: dry and scaly skin, liver abnormalities, poor wound healing, growth failure in infants, and impaired hearing and vision.

how fat is stored and retrieved: fat retrieval - fasting

- if consume less energy than needs then you have to use up fat. - when no food has been eaten for a while, triglycerides from adipose tissue are broken down, releasing fatty acids as an energy source - hormone-sensitive lipase (in adipocytes) breaks down stored triglyceride - fatty acids + glycerol releases directly into blood for use by cells throughout body to produce ATP. - if there is not enough carbohydrate to allow acetyl CoA form fat breakdown to enter the citric acid cycle , it will be used to make ketones. Ketones can be used as an energy source by muscles and adipose tissue. During prolonged starvation, the brain can adapt to use ketones to meet about half of its energy needs. For the other half it must use glucose. - even a lean man can have thousands of kcal stored as TGs in adipose tissue

lipids in the digestive tract (2)

- in healthy adults, most of digestion of dietary fat takes place in the small intestine due to the action of lipid digestion enzyme calle lipase. - A small amount of triglyceride digestion also occurs in the stomach due to the action of gastrin lipase, an enzyme that can act in the acidic environment of the stomach. Gastric lipase is particularly important in infants because it helps digest fat in milk - the pancreas produces the enzyme pancreatic lipase, which is released into the small intestine to aid int he digestion and absorption of fat. - in the small intestine, bile stored in the gall bladder (produced by the liver) helps break fat into small globules. The triglycerides in the globules are digested by lipase from the pancreas, which breaks them down into fatty acids and monoglycerides. These products of triglyceride digestion, cholesterol, another fat-soluble substance, including fat-soluble vitamins, mix with bile to form smaller droplets called micelles. - micelle have a fat soluble center surrounded by a coat of bile acids. They facilitate the absorption of lipids into the mucosal cells of the small intestine by allowing these substance to get close enough to the microvilli to diffuse. - inside the mucosal cells, fatty acids and monoglucerides are reassembled into triglycerides and incorporated into lipid transport particles which enter the lymph. - since fat absorption in the small intestine is efficient, very little fat is normally lost in the feces. - gastric lipase acts on triglycerides with short and medium chain fatty acids. - fat soluble vitamins are absorbed with fat.

lipid function in the body: 1. lipids provide structure and lubrication

- most lipids in the body are triglycerides stored in adipose tissue. - deposits of adipose tissue: help to define body shape (adipose tissue under the skin), provide stored energy, insulate the body from temperature changes, protect internal organs against the physical shock (adipose tissue surrounds organs). - lubricate body surfaces, such as the mucous membranes of the eyes. - needed for absorption of fat soluble vitamins. - cholesterol: making hormones including sex hormones (estrogen, testosterone) and stress hormones (cortisol), makes bile acids, makes myeline (insulates nerves), part of structure of cell membranes - essential fatty acids: omega 6 (linoleum acid), omega-3; important for growth, integrity, fertility, and the structure and function of cell membranes - eicosanoids: hormone-like molecules, made form long chain omega-3 and omega-6 fatty acids, help regulate blood clotting, blood pressure, and immune function. effects can be different depending on which "family;" omega-6 family promotes blood clotting, omega-3 has to opposite effect.

cardiovascular disease

- over 83 million Americans suffer from some form disease affecting the heart or food vessels. - studies show that diet and lifestyle affect the risk of developing CVD: Giets high in cholesterol, saturated fat, transfer have been linked to CVS - atherosclerosis: disease in which lipids and fibrous materials are deposited in artery walls. Reduces elasticity of vessels. contributes to blockage of blood flow.

Lipids contribute ____, ____, and ____ to foods. They are known as "____"

- texture, taste, aroma - feel good foods

fatty acids: chain length

- the carbon chain of fatty acids vary in length from a few to 20 or more carbons. Most fatty acids in plants and animals including humans, contain between 14 and 22 carbons. - the chain length affects the characteristics of the fatty acid. - short chain fatty acids are fairly soluble in water - with increasing chain length, the fatty acids become less and less soluble in water - short chain fatty acid: range from 2-7 carbons and remain liquid at colder/refrigeration temperature (i.e. milk) - medium chain fatty acids: 8-12 carbons long, solidify in the refrigerator but remain liquid at room temperature (i.e. coconut oil) - long chain saturated fatty acids: greater than 12 carbons, usually sold at room temperature (i.e. beef fat)

sources of fat in our diet

- the typical American diet includes about 34% of its energy from fat. - a high fat diet can make it easier to consume excess energy and be in positive energy balance. - most of the fat that is naturally present in foods is round in meats, dairy products, nuts, seeds, and vegetable oils. - processed foods and baked goods are sources of less visible fats - in general, fruits, vegetables, and grains are low in fat unless we add them. - ex: french fries start as potatoes (low in fat) but when immersed in hot oil for frying, they soak up fat. - you would have to add 4 pats of butter to met the same fat value as french fries

how lipids are transported from the liver?

- these lipoproteins transport lipids within the body. - even when you have not recently eaten, these molecules are circling and transporting lipids. - very low density lipoproteins, low density lipoproteins, high density lipoproteins,

how lipids are transported from the small intestine

- to be transported from the small intestine, long-chain fatty acids and monoglycerides must first be assembled into triglycerides by the mucosal cell. these triglycerides are then combined with cholesterol, phospholipids, and a small amount of protein to form lipoproteins called chylomicrons - chylomicrons are too large to enter the capillaries in the villi of the small intestine, so they pass from the intestinal mucosa into the lymphatic system, which then delivers them to the blood without first passing through the liver. - as chylomicrons circulate in the blood, the enzyme lipoprotein lipase, present on the surface of the cells, lining the blood vessels, breaks the triglyceride down into fatty acids and glycerol, which enter the surrounding cells. the fatty acids can be either used as furl or resynthesizes into triglycerides for storage. What remains of the chylomicron is a chylomicron remnant composed mostly of cholesterol and protein. this goes to the liver and is disassembled.

heart disease risk factors: blood lipid levels

- total cholesterol should be lower than 300. High risk would be greater than 240. - LDL cholesterol should be less than 100 or less than 70 in high risk individuals. High risk would be greater than 160. - HDL cholesterol should be greater than 60. high risk would be less than 40. - triglycerides should be less than 150

how dietary fat affects health

- transfat may be worse than saturated fat - foods that we should eat less of are high in saturated fat and cholesterol (big problem) - cholesterol is an animal sterol - foods that we should eat more of are low in saturated fat and cholesterol, high in unsaturated fat, plant products that contain no cholesterol. We should be eating more whole grains, fruits, and vegetables.

chylomicrons and VLDLs

- transport and deliver triglycerides to body cells - to enzyme lipoprotein lipase (LPK) present on endothelial cells lining blood capillaries, break down and remove triglycerides from chylomicrons and VLDLs

lipid absorption

- triglycerides are absorbed int the mucosal cells as monoglycerides and fatty acids . -once inside the mucosal cell, long-chain fatty acids, cholesterol and other fat-soluble substances require further processing before they can be transported through the blood.

types of lipids: 1. triglycerides and fatty acids

- triglycerides are the major form of lipids in food and in the body. - triglycerides consist of three fatty acids attached to a glycerol molecule. - monoglyceride: when only one fatty acid is attached to the glycerol - diglyceride: when two fatty acids are attached to the glycerol - fatty acids added to the glycerol = condensation reaction. the acids are "neutral" after attachments because they are no longer an acid

how triglycerides provide energy

- triglycerides serve as your energy source through metabolism - fatty acids and glycerol can be used to produce energy in the form of ATP. - BETA oxidation of fatty acids: begins in the metabolic pathway to produce ATP, occurs within the mitochondria of the cell. Splits the carbon chains into 2 chains into 2 carbon units that form acetyl CoA and high energy electrons - Acetyl CoA entering the Krebs Cycle: requires adequate oxygen and oxaloacetate from CHO. Results in production of CO2 and high energy electrons/ - electron transport glycerol molecules: used to produce small amounts of ATP or converted to glucose

unsaturated fatty acids:

-contain some carbons that are not saturated with hydrogen atoms. The carbon pairs within the chain that are bound to only one hydrogen form carbon-carbon double bonds. - plant products = major source of unsaturated fatty acids - products rich in unsaturated fatty acids = liquid at room temperature and cooler temperatures (ex: vegetable oils) - monounsaturated and polyunsaturated fatty acids are unsaturated fatty acids - the essential fatty acids omega-3 and omega-6 are unsaturated fatty acids. - trans fatty acids are also unsaturated fats

lipid transport and delivery

1. Chylomicrons formed in the mucosal cells pass first into the lymph, which drains into the blood. They circulate in the blood, delivering triglycerides to body cells. 2. The enzyme lipoprotein lipase, which is present on the surface of cells lining the blood vessels, breaks down the triglycerides in chylomicrons into fatty acids and glycerol. These can then enter the surrounding cells. 3. The chylomicron remnants that remain after the triglycerides are removed travel to the liver to be dissembled. 4. VLDLs are made in the liver and transport lipids away from the liver. They function similarly to chylomicrons because both particles deliver triglycerides to body cells with the help of enzyme lipoprotein lipase. 5. The IDL particles that remain after the triglycerides are removed wither returned to the liver or transformed in the blood into LDL particles. 6. To deliver cholesterol, LDL particles bind to LDL receptors in the cell membrane. This allows the LDL particle to enter the cell, where the cholesterol and other components can be used. 7. HDL particles pick up cholesterol from other lipoproteins and body cells and return it to the liver. Some of this cholesterol is broken down and some is transferred to organs with high requirements for cholesterol, such as those that synthesize steroid hormones.

lipids and cardiovascular disease

1. Normal artery: The wall of a normal, healthy artery is lined with a layer of endothelial cells that are surrounded by smooth muscle. 2. Damaged artery: damage to the lining of an artery causes inflammation and begins the process of plaque formation. The injury attracts white blood cells, which mature into macrophages and makes the lining more permeable to LDL particles. Inside the artery wall LDL is oxidized to form oxidized LDL cholesterol 3. Plaque formation: Inside the artery wall, macrophages fill up with oxidized LDL cholesterol and are transformed into foam cells. These cells get so full that they burst, depositing cholesterol. The accumulation of cholesterol and proteins forms a plaque. 4. Plaque enlargement: As inflammation continues, plaque builds up, causing the artery to narrow and lose its elasticity. A cap of smooth muscle cells and fibrous proteins forms over the plaque , walling it off from the lumen of the artery. 5. Plaque Rupture: If the inflammation continues, the fibrous covering the plaque degrades. If the cap ruptures or erodes, blood clots can rapidly form around it. The blood clots can completely block the artery at the spot or break loose and block an artery elsewhere. 6. heart attack: if blood flow in a coronary artery is blocked, a heart attack results. Heart muscle cells are cut off from their blood supply ad die, causing pain and reducing heart's ability to pump blood.

dietary fat and obesity 1. factors that increase risk 2. factors that decrease risk 3. factors that decrease the risk (2)

1. cholesterol, saturated fat, trans fat, sodium, excess sugar, excess energy 2. polyunsaturated fats, monounsaturated fats, B vitamins, antioxidants, moderate alcohol. 3. whole foods -fish is high in omega-3 fatty acids, which reducethe risk of heart disease. Lowers LDL by decreasing blood clotting and lowering blood pressure - nuts are a good source of monounsaturated fat, which lowers LDLcholesterol. Nuts are also high in omega-3 fatty acids, fiber, vegetable protein, and antioxidants - oatmeal and brown rice are good sources soluble fiber, which have been shown to reduce blood cholesterol levels. Whole grains also provide omega-3 fatty acids, B vitamins, and antioxidants. - plant sterols reduce cholesterol absorption, lowering total and LDL cholesterol levels. Plant sterols are found in vegetable oils, nuts, seeds, cereals, legumes, and many fruits and vegetables and are added to special margarines, salad dressings, and orange juice. - moderate consumption of dark chocolate is associated with reduced risk of heart disease - moderate alcohol consumption reduces blood clotting and increases HDL cholesterol. - soy can lower the risk of heart disease

polyunsaturated:

2 or more unsaturated links (2 or more double bonds) contain more than one carbon-carbon double bond.

dietary fat and obesity

Dietary guidelines for Americans 2010 recommendations - saturated fatty acids should be less than 10% of calories. less than 7% reduces risk of CVD further. replace with poly and monounsaturated fatty acids (not with sugar or refined grain) - trans fat --> low as possible - cholesterol --> less than 300 mg per day

the role of reduced fat foods and fat replacers

Reduced fat foods either have fat removed, have fat replaced (mimic taste and texture) or contain fats that cannot be digested or absorbed. - Depending on the food may or may not increase the nutrient density of diet. Fat substitutes can be carbohydrate-, protein-, or fat-based. Using too much can increase energy in the diet Fat based fat substitutes such as Olestra (sucrose polyester [fatty aids attached to a molecule of sucrose]), can reduce the absorption of fat-soluble vitamins - Olestra cannot be digested and provide no calories - Polysaccharides such as pectin and gums are often used in baked goods, salad dressings, sauces and ice cream. These thicken foods and mimic the slippery texture that fat provides. They reduce the amount of fat in a product and at the same time add soluble fiber. - The sugar sucrose is usually added to low fat and nonfat baked goods to improve flavor and add volume. Sucrose adds 4 kcalories per gram, - Protein based fat replacers are made from milk and egg proteins processed that mimic a creamy texture of fat. Used in frozen desserts, cheese foods, and other products but cannot be used for frying because they break down at high temperatures

Guidelines for prevention of certain diseases

To reduce risk of heart disease - <7% of calories should be saturated fat - cholesterol should be <200 mg/day - Total fat should be 25-35% of calories Diets to reduce cancer risks - Choose mostly plant foods, limit red meats and processed meats - Choose more whole grains, nuts, and seeds - Eat plenty of fruits and vegetables - Maintain a healthy weight throughout life - Avoid sugary drinks, choose energy dense foods, exercise portion control - Be physically active for at least 30 minutes a day - Limit alcohol drinks to 2 for men and 1 for women a day - Limit consumption of salty foods and foods processed with salt.