4.Nutrition and metabolism of lipids

Question 1

why do we need lipids?

Answer 1

• membrane structure
• fat soluble vitamins(A,K,E,D)
• energy storage
• insulation and protection
• building blocks for hormones
• flavour and texture

Question 2

Which is the requirement for fat intake?

Answer 2

It should be 25-35 % of total energy infake

Question 3

Definition of lipids

Answer 3

Organic compounds soluble in organic solvent (benzene)

Question 4

Which are the main dietary lipids?

Answer 4

-mono, di, triglycerides
-phopolpids and glycolipids
-lipoproteins
-fatty acids
-sterols
fat soluble vitamins

Question 5

Which are the main sources of lipids?

Answer 5

meat, fish, egg, dairy products, cheese, seets and cakes

Question 6

n-3 and n-6 fatty acids

Answer 6

n3 fatty fish, linseed, flaxseed, algae
n6: corn oil, sunflour oil, soybean oil
N3/n6 is 1:15

Question 7

What are the trans fats:

Answer 7

mainly from hydrogenation of plant oils to make them solid, only low amount is allowed in food

Question 8

Describe the absorbtion of lipids:

Answer 8

tryglicerydes are broken own in the intestinal lumen by pancreatic lipase in glycerol and fatty acids
BUT PROBLEM CAUSE ARE NOT WATER SOLUBLE
micelles–> chylomicrons fo through lymph into blood

Question 9

Exogenous pathway lipids:

Answer 9

intestine-> chylomicron->capyllary->lipoprotein lipase -> adipose tissues and what remain goes into liver and split into free fatty acids and sholesterol

Question 10

endogenous pathway

Answer 10

fatty acids and cholesterol in the liver are assempled in bery low density lipids then transported into the capillary again, some will go in the adipose tissue, some in the peripheral tissues

Question 11

describe what is the beta oxydation

Answer 11

it converts fatty acids in energy: c18:o is 120 ATP

Question 12

Problem about cholesterol?

Answer 12

Elevate low density lipoproteins are associated with increased caridovascular disease
reduce cholesterol intake: does it help? NO
Plant sterols can contribute to low the cholesterol absortion (sitostanol)

Question 13

Cholesterol metabolism

Answer 13

From diet and endogenous synthesis and it goes in to the bile and in other metabolism

Question 14

Explain correlation between cholesterol and CVD risk

Answer 14

HIgh amount of cholesterol lead to greater risk to cholesterol deposit (arthrosclerosis) inside of blood vessels.
Increasing HDL seems to not improve the CVD outcomes

Type of FAT is important in the diet!

Question 15

Interaction between carbohydrate metabolism and lipid metabolism

Answer 15

Glucose metabolism is controlled by insulin, insulin play a role in lipid metabolism and distribution:

• stimulate lipoprotein lipase
• inhibits intracellular lipolysis
• suppresion of VLDL secretion from liver

Question 16

How insulin drive the carbohydrate and fat metabolism?

Answer 16

When liver is full of glycogen, all the glucose that enter the body is driven to synthesize fatty acids taht are transported in the liver as lipoproteins. The insulin try to prevent the fat to be taken up, it want to break down the carbohydrates first for the energy instead of fat. In fact, insulin stimulat the fat accumulation in the adipose tissues.

Question 17

Main funcitons of lipids in the central nervous system?

Answer 17

DHA, AA main components of neuronal membranes

• direct signalling
• influence of endo-exocytosis
• precursor of endocannabinoids
• inflammatory up and down regulation

Question 18

Examples of fatty acids and health

Answer 18

-omega3 fatty acids good for pregnant women as well as long chain polyinsaturated fatty acids
n3 polyinsaturated fatty acids are good for children cause increase the cognitive peroìfromances

Question 19

evolution of diet and weight loss

Answer 19

before fat and now carbohydrates
factor contributing to fat:
composition, genetics, processing, microbiota, carbohydrates