Nutrition Chapter 4: Lipids

What are the essential tasks performed by adipose tissue? (7)

1. storage source of energy 2. thermal insulation 3. protection of vital organs 4. transmission of nerve impulses 5. form membrane structure 6. carrier of fat-soluble materials (lipoproteins) 7. precursor of other substances (brain tissue and retina)

Health concerns r/t dietary fat focus on which two issues?

1.) the high energy content of fat 2.) the negative effects of certain fatty acids.

What are the functions of food lipids? (5)

1. Provide energy (9kcal/g),2. supply essential fatty acids, 3.support absorption of fat soluble vitamins (DEAK), 4.add to food palatability (flavor) 5. promote satiety

Saturated fats

comes from two oil plants (coconut oil and palm kernal oil) all others come from animal origin (meat, butter, and whole milk dairy products

How are lipids transported?

compounds called phospolipids located in the cell membranes help lipid molecules move from the circulatory system into the cell.

What role does arachidonic acid and docosahexaenoic acid play in infant development (both found in breastmilk)

ensure brain and neural development

What is the only gastric secretion specific to lipids?

enzyme gastric lipase (tributyrinase), which acts on emulsified butterfat.

a-linolenic acid

essential fatty acid for human; an n-3 polyunsaturated fatty acid

Linoeic acid

essential fatty acid for humans; an n-6 polyunsaturated fatty acid

What are the roles cholesterol plays for normal body function? 4

1. precursor to steroid hormones (estrogen and testosterone), 2.formation of bile acids 3. component of brain and nerve tissue 4. component of cell membranes

What roles do the essential fatty acids play in our body? (7)

1. skin integrity 2.regulation of blood cholesterol 3. gene expression 4. immune function 5. aggregation of blood platelets 6. synthesis of hormone-like agents

What happens when inappropriate high intakes of fish oil supplements are consumed?

excessive bleeding and interfere w/ other aspects of fatty acid metabolism

Lipids

fats and fat-related compounds such as cholesterol, lipoproteins, and phospholipids

What are the adequate Intake (AI)s of the two essential fatty acids? women, men

For linoleic acid: 17g/day for men and 12g/day for women ages 19-50 yrs. over 51, 14g/day for men and 11g/day for women. For a-linoleic acid: 1.6g/day all adult men and 1.1g/day for all women

Where are glycerides found?

food and also formed in the body (most natural lipids from animal or plant sources are triglycerides).

How does the body store fatty acids?

in the form of triglycerides made from three fatty acids attached to a glycerol base.

How do lipoproteins function in the body?

liver is the body's clearinghouse for fatty acids and cholesterol (supplied or produced in body tissues), when they are received by the liver they are packaged into lipoproteins and then released into the circulation for transport to cells.

Lipoproteins

major carriers of lipids in the plasma, combination of fat surrounded by protein makes possible the transport of fatty substances in a water medium such as plasma

Give examples of polyunsaturated and monosaturated fats.

mono, generally from plant sources (canola and olive oil) poly, plant sources often used in cooking (corn, safflower and vegetable oils)

essential fatty acids

must be supplied in diet b/c the body can't make them or can't make in sufficient amounts

Eicosapentaenoic acid

n-3 polunsaturated fatty acid synthesized by the body in limited amounts from a-linolenic acid and can be obtained from fish oil, helps lower the risk of heart attack or stroke

docosahexaenoic acid

n-3 polyunsaturated fatty acid synthesized by the body obtained from fish oil: important for brain and neural development in infants and helps lower the risk of heart attack or stroke

What are the food sources of cholesterol?

only in animal foods: egg yolk, meat, whole milk, cheese, and organ meats

Which fats have positive effects on the body?

polyunsaturated and monosaturated

Hydrogenation

process used to produce margarine and shortening from vegetable oils are exposed to hydrogen atoms are added at many of the double bonds of the polyunsaturated fatty acids, forming a solid fat.

Where are trans fats found?

produced in the commercial processing of lipids (best if eliminated from diet, very bad)

Where are saturated fats and cholesterol found?

saturated found primarily in animal sources, cholesterol found only in animal foods

Where are unsaturated fats found?

vegetable oils and fatty fish

What are the best sources of the two essential fatty acids?

vegetable oils: corn oil, safflower oil, soybean oil, cottonseed oil, sunflower oil and peanut oil all contain linoleic acid. a-linolenic acid found in canola oil, linseed oil, rapeseed oil, and dark-green leafy vegetables.

What are the 3 sources for lipid breakdown in the small intestine?

1.)Bile from the liver and gallbladder: presence of fat releases CCK, which causes gallbladder to contract releasing bile ,2. enzymes from the pancreas: pancreatic lypase breaks off the fatty chains, 3. enzyme fro the small intestine: Lecithinase acts on lecithin a phospholipid!

What are the Acceptable Macronutrient Distribution Range (AMDR) for fat?

20% to 35% of total kcalories

How much does the American Heart Association recommend?

300 mg/day or less

What are the 5 classes of lipoproteins?

Chylomicrons, Very low-density lipoproteins (VLDLs), Intermediate-density lipoproteins (IDLs), LDLs , HDLs

Where and what begins the process of lipid digestion?

Mouth, with lipase from the salivary secretions

Which fats add to health risks?

Saturated and Trans fats

Tryglycerides

a neutral fat synthesized from carbohydrate and stored in adipose tissue, it releases free fatty acids into the blood when needed for energy

Cholesterol

a sterol normally found in bile (contributes to gallstones), synthesized by the liver and is a precursor of various steroid hormones, such as estrogen, and testosterone, and of the vitamin D molecule produced by the action of UV light on the skin. found in animal tissues such as meat, egg yolk, and milk fat

What are some major sources of hidden fats?

bakery items such as cakes, muffins, cookies, crackers and even frozen entrees such as lasagna

Fatty Acids

building blocks or structural components of fats

Organic

carbon-based chemical compounds

Adipose

cells and tissues that store fat