Nutrition Exam - Fats

- a family of compounds insoluble in water.

- Fat is solid at room temp

- Oils are liquid at room temp

- Some fatty acids are essential nutrients

- carry fat soluble vitamins

- provide energy

- increase satiety value of foods

- enhance taste and aroma

- provide moisture

- serve as energy source especially for muslces

- contribute to a feeling of fullness at a meal by slowing digestion

- enhance foods aroma and falvour

- cushion the vital organs

- prtoect the body from extreme temperature

- carry fat soluble vitamins ADEK

- provide essential fatty acids as part of fat

- Provide the major material of which cell membranes are made

- Provide compact energy reserves

- major consitituent of cell membranes

- cushion organs

-assist in temperature regulation

- Visceral: surrounds organs. affected by diet and excersise

- Subcutaneous: thin layer beneath the layer of skin

Gynoid: fat distributed more around hips and but

Android: fat distributed around stomach.

- store fat

- can vary in number and size

- LPL: lipoprotein lipase

- HSLPL: hormone sensitive lipoprotein lipase

1. Triglycerides (TG) - fats and oils . 95% of lipids in foods and humans are TG. energy reserves.

2. Phospholipids - lecithin in one phospholipid. cell membranes, many special functions (eyes, nerve sheath)

3. Sterols - Cholesterol is best known. cell membranes, steroid hormones, bile salts, vitamin D.

- 95% of fat in food and body

- Made up of glycerol and 3 fatty acids (3 C's)

- The length: the more carbon atoms a fatty acid contains the longer it is. 8-22 carbons. usually even. can be saturated, monounsaturated, and polyunsaturated.

- The degree of saturation: the more hydrogen atoms a fatty acid contains the more saturated it is.

1. Saturated - every body from carbons is holding a hydrogen.

2. Unsaturated - a fatty acid in which a bond from a carbon has an empty spot where hydrogens are missing. Mono: one point of unsaturation. Eg olive oil or canola. May have heart benefits. Poly: two or more points of unsaturation.

- animal fat is saturated

- vegetable and fish are unsaturated with the exception of coconut (heart harm) and palm oil

- soft fats consist of fatty acids that are shorter and more unsaturated which melt more easily or have a low melting point

- hard fats consist of fatty acids that are long and more saturated and have a higher melting point.

- Some fatty acids must be obtained in food. We canoot make them or we cannot make them in sufficient quanitites to meet out bodys needs.

- Linoleic acid = omega 6 fatty acid = C:18:2 w-6

- arachiconic acid = C20:4 w-6

- Linolenic acid = omega 3 fatty acid = C18:3 w-3

- EPA = 20:5 w-3

- DHA = 22:6 w-3

- Regulate blood pressure, blood clot formation, blood lipids, immune response

- body can make longer chain members of either family if the 18 carbon form is available.

- the body cannot convert from one family to another.

- used to make eicosanoids which are biologically active compounds involved in the above things.

- makes unsaturated fats more saturated

- makes liquid fats more chemically stable (useful for making stable fats and deep frying)

- males liquif fats more solid which is useful for making fats you can spread and useful for making vegetable shortening.

- tend to be cis in nature

- process of hydrogenation can create trans double bonds

- a class of lipids with complicated structure similar to cholesterol.

- cholesterol plays roles as part of the emulsifier called BILE and is used to make other sterols like vitamin D and steroid and sex hormones.

- cholesterol is part of brain cells and nerve cells

1) Mouth: particle size decreases. lingual lipase (in stomach and infants) converts triglycerides to diglyercides and fatty acids.

2) Stomach: TG enter where very little digestion takes place.

3) Small intesine LUMEN: bile salts released to emulsify fat. (also recirculation of bile salts). Pancreatic lipase released to digest fat into monoglycerides and 2 fatty acids.

- glycerol

- monoglycerides

- Individual fatty acids: some long chain, some medium chain, and some short.

- Intestinal cells absorb fats but they must get across the watery mucus membrane.

- small lipids can travel alone in the blood after absorption. glycerol and short and medium (10-12 or less) go directly in blood.

- LARGE lipids must be incorperated into transport molecules in order to pass across cell membranes.

- collectively, transport molecules for fats are called lipoproteins. MICELLS AND CHYLOMICRONS

- get surrounded by bile and form a MICELLE to get into the intestinal cell

- inside the cell they are bonded to glycerol and reassemble into triglycerides.

- now they join with other fats such as cholesterol, phospholipids and also protein (attract both fat and water becuase they are emulsifiers) to form a lipoprotein

- the lipoprotein formed into the intestinal cell is a CHYLOMICRON

- monoglycerides and long chain fatty acids.

- instead go into lymphatics or lymph

- go through the thoracic duct.

- transport triglycerides, cholesterol, phospolipids and protein,

- first in lymphatics

- then into the blood circulation at the thoracic duct at the back of the heart where the lymphatic circulation system joins the blood circulation system.

- special lipoprotein that carries fat from the small intestine to the body cells and liver.

- some is absoribed into the blood and resused

- some is excreted in feces.

- they carry lipids in the blood

- made up of a phospholipid coat, proteins in coat act as identifying markers, have a TG and Cholesterol core.

- the higher the protein content of the lipoprotein the higher the density.

- cholymicrons.

- very low density lipoprotein VLDL

- intermediate density lipoprotein IDL

- low density lipoprotein LDL

- high density lipoprotein HDL

- large particles

- mainly triglycerides

- formed in the intestinal cell

- found in high concentrations after a high fat meal

- cleared from the blood within 12-14 hours

- as they pass by, body cells remove fat from chylomicrons - LPL

- remnants picked up by the liver cells.

- made by liver cells

- largely composed of triglycerides 55-65%

- smaller quantities of cholesterol, phospholipids and protein

- breakdown into IDL before becoming LDL

- formed in the plasma during the conversion of VLDV to LDL

- contain considerable amounts of triglyceride and cholesterol.

- Derived from the conversion of CLDL to IDL as body cells remove triglycerides from them.

- Around half of LDL is composed of cholesterol

- The contents of LDL is available to all cells

- More lipid, less protein.

- Synthesized in the liver and intestine.

- picks up cholesterol from tissues and sens it to the liver

largely composed of protein, and less lipid

- increased amounts of HDL protect against atherosclerosis

- high density

- raise LDL in blood

- lower HDL in blood

- Increase oxidation of fat in LDL so increase heart disease.

- inflammatory process causing plaques to accumulate on and in the walls of blood vessels

- it changes the functional capacity of the blood vessels (blood flow and elasticity: arteriosclerosis (hardening of arteries))

- a thrombus is a blood clot. if it blocks a vessel in the heart can cause a heart attack of myocardinal infarction.

- if blockage occurs in the brain = stroke

- Simplesse: digested and absorbed and contributes on 4 calories per gram

- Olestra (sucrose plus eight fatty acids): not digested and absorbed. 0 calories. has side effects causing cramps, and pooing. binds vitamin E and K, so not approved in Canada.

- Long term effects unknown.

- when low on fuel and cells need energy, the cells call on stored fat for energy

- TG stored in cells break down to FA and glycerol and on to CO2 and H20 and ENERGY (beta oxidation)

- glucose is necessary for complete breakdown of fat. Fat fragments combine with fragments of glucose

- without carbs, ketosis occurs.

- to control blood cholesterol with diet:

- lower total fat in diet

- lower saturated fat in diet

- lower trans fat

- lower cholesterol

- eat foods that contain Vitamin D and E as these are antioxidants (control for the oxidation of fat in LDL)

- Saturated fats in foods raise blood cholesterol more than cholesterol.

- having moderate fat consumption

- too high = increased body fat leading to increased LDL cholesterol

- too low = decreases intake and absorption of fat soluble vitamins. decreases essential fatty acids. possibly decreases HDL cholesterol.

- reducing saturated fat = high intake of LDL cholesterol

- Reducing trans fats = do it. they are horrible.

- want moderate PUFA intake: most chemically reactive fats. (n6 and n3) pufas are the efas.

- recommended: no more than 35% of energy from fat and no more than 10% of energy from saturated fat.

- LDL - contains little protein and mostly cholesterol. transports cholesterol and fats from liver to cells. BAD because when high increases risk of heart attack

- HDL - high protein. brings cholesterol from teh cells back to liver. GOOD becuase lowers risk of heart attack.