lecture 12-14 - Fats and Lipids

Question 1

Lipids

Answer 1

Any of a class of organic compounds that are fatty acids of their derivatives and are insoluble in water but soluble in organic solvents (include many natural oils, waxes and steroids)

Question 2

Lipids functions

Answer 2

Energy, structural, signalling (metabolism), provides insulation, cushions internal organs

Question 3

Triglycerides (Glycerol + 3 fatty acids)

Answer 3

90% of dietary lipid, energy storage, fatty acid storage, structural component of lipoproteins

Question 4

Fatty acids

Answer 4

Chains or carbon molecules with a methyl group at one end of the chain and a carboxyl group at the other end

Question 5

Fatty acids types

Answer 5

Saturated (no double bonds), monounsaturated (1 double bond) polyunsaturated (more than one double bond), Double bonds affect melting point (Cis vs trans bonds, trans fatty acids act like saturated fatty acids and change melting point) (position of first double bond from methyl end n-3 air n-6

Question 6

Essential fatty acids

Answer 6

Linoleic acid (C18:2w6), Linolenic acid (C18:3:w3, cis bond) Humans unable to make the double bond with the first 6 carbons from the methyl end (deficiency = growth retardation, reproductive failure

Question 7

Phospholipids

Answer 7

Glycerol backbone + fatty acids (hydrophobic) + phosphate group(hydrophilic) many roles in diet (cell membranes, plasma lipoproteins)

Question 8

Fat Intake (ANS 08/09)

Answer 8

No specific intake of grams of fat, AMDR 20-35% total energy, main sources of fat in NZ diet, butter/margarine, potatoes, kumara, taro, bread-based dishes, etc

Question 9

Lipids (Fat) digestion

Answer 9

Fat digestion starts with physical digestion in the mouth, chemical digestion involving saliva, key enzymes in the mouth being lingual lipase and phospholipids, Fat in the stomach separated from other food substances, In small intestine bile (produced by the liver, store in the gall bladder) emulsifies fats while enzymes like lipase break it down (digest) to monoglyceride, glycerol and fatty acids

Question 10

Lipid Metabolism

Answer 10

Fatty acids (monoglyercide, glycerol, etc) absorbed by bushed border on microvilli and transported to liver via hepatic portal vein. Fatty acids then used in body for energy, structural, signalling to provide insulation and as a cushion that protects internal organs (storage)

Question 11

Types of Lipoproteins

Answer 11

Chylomicron (highest triglyceride composition, lowest protein composition)
Very low density lipoprotein (higher in triglyceride composition, relative low protein composition)
Low-density lipoprotein (Relativelylow triglyceride content, higher protein composition, more cholesterol) High density lipoprotein (Lowest triglyceride composition, highest protein composition)

Question 12

Cardiovascular disease risk factors

Answer 12

Age, gender (non-modifiable), smoking, PAL, total cholesterol high (LDL cholesterol high, makes up most body cholesterol), high BMI, diabetes, blood pressure (Modifiable by diet/lifestyle choices)