Lecture 5 - Lipids

Question 1

What is the need for fat in the diet?

Answer 1

There is no specific requirement for fat except for the essential fatty acids. It is hard to eat a low fat diet to meet energy requirments. Fat lubricates food making it easierr to eat and also gives the food flavour.

Question 2

What are lipids ?

Answer 2

Organic molecules

Question 3

Can lipids dissolve in water?

Answer 3

No

Question 4

What do lipids contribute to in regards to food?

Answer 4

Texture, flavour, crispiness and aroma. Also juiciness and tenderness.

Question 5

How many lipids does the average american diet consist of ?

Answer 5

33%

Question 6

What does fat free mean?

Answer 6

Less than 0.5 g of fat per serving

Question 7

What does reduced fat mean?

Answer 7

25% less than the natural counterpart

Question 8

What does light mean?

Answer 8

1/3-50% less fat then the regular product.

Question 9

What are triacylglycerols?

Answer 9

It is most commonly found in food and stored in the body. Its properties are determined by the fatty acids they contain.

Question 10

Unsaturated vs saturated fats?

Answer 10

unsaturated has double bonds and is healthier.

Question 11

Cis vs trans?

Answer 11

The difference between cis and trans fatty acids is that the cis fatty acids have two hydrogen atoms attached to the double bond in the same side of the carbon chain whereas the trans fatty acids have the two hydrogen atoms bonded to the double bond in the opposite sides of the carbon chain

Question 12

Why trans fatty acids are bad?

Answer 12

bc they cause inflammation increasing the risk of CHD.

Question 13

What are the two essential fatty acids?

Answer 13

Omega 6 - linoleic acid

omega 3 - alpha-linolenic acid.

Question 14

What is omega 6 important for?

Answer 14

it is important for growth, skin integrity, fertility, RBC structure

Question 15

What is Omega 3 important for?

Answer 15

It is important for structure and function of the cell membranes.

Question 16

The essential fatty acids are precursors for what and what does it do?

Answer 16

Precursors for eicosanoids (prostaglandins) - regulating blood clotting, blood pressure, immune function, and other body processes.

Omega 6 - for arachidonic acid
Omega 3 - for eicosapentanoic acid and docosahexanoic acid

Question 17

What are sources of omega 3?

Answer 17

1. ) seed oils (linseed, rapeseed, soya, walnut) but typically seeds contain omega 6.
2. ) Meat from grass fed animals
3. ) Green leafy veg (spinach)
4. ) Long chain derivatives are found in fish oils.

Question 18

Effects of omega 3?

Answer 18

Reduce the risk of fatal heart attack by just having 1 gram a day. Protect agaisnt cardiac arrythmias and reduces the development of artherosclerosis.

Thin the blood - decreasing inflammation (protect from arthiritis)

Effect on cancer not proven yet

Question 19

What ratio of omega 6 to 3 is taken in western diet vs what should be taken?

Answer 19

wester diet - omega 6/ omega 3 - 10/1 or 30/1

should be 1/1 or 1/4.

Question 20

What is cholestrol?

Answer 20

Made only in animals in the liver and it is a component of the cell membrane and myelin. It is needed for the synthesiis of vitamin d, bile and some hormones.