21 metabolic fate of nutrients

Question 1

What happens to fructose and galactose in the liver?

Answer 1

they’re converted into glucose

Question 2

What is glycaemic index?

Answer 2

ranking of carbohydrates on a scale of 0-100 according to the extent to which they raise blood sugar levels after eating particular food types

Question 3

What is the difference in insulin response to high GI foods vs low GI foods, what is the significance of this?

Answer 3

high GI foods will prompt a much greater insulin response, this will temporarily reduce bgl, increasing appetite, so people with very sugary diets will be able to eat for longer

Question 4

What 3 types of fats do we get from our diet?

Answer 4

TG’s (essential fatty acids, linoleic, linolenic, and arachidonic acid)
phospholipids
sterols (mainly cholesterol)

Question 5

Why is weight loss so hard?

Answer 5

all fats contain about 9kcal/kg, they are very calorie dense, requiring loads of oxygen to metabolise. They’re also insoluble in water to very difficult to access

Question 6

How are fats metabolised?

Answer 6

all converted into fatty acids and glycerol
fatty acids undergo beta oxidation into acetyl co-A
glycerol is converted to glucose and then undergoes glycolysis to pyruvate….

Question 7

What do we do with excess amino acids?

Answer 7

we can’t store them! so we do need a regular supply

Question 8

HOw do we absorb and excrete nitrogen?

Answer 8

absorbed in amino acids

excreted in urea and ammonia i think

Question 9

Name one advantage of fats as an energy source

Answer 9

contain 2x the amount of energy per unit weight compared to carbs

Question 10

Name one disadvantage of fats as an energy source

Answer 10

needs 4x as much oxygen to metabolise compared with the oxidation of glucose

Question 11

WHat are the 2 main categories of dietary fibre?

Answer 11

insoluble and soluble fibre

Question 12

What function does insoluble dietary fibre offer?

Answer 12

provides bulk, preventing constipation, and reduces dumping syndrome, by slowing gastric emptying, retarding glucose absorption

Question 13

What function do soluble dietary fibres offer?

Answer 13

absorb water in the inteting, softening stool
lowers cholesterol
reduces bowel cancer risk

Question 14

How might soluble ditary fibres limit your risk of bowel cancer?

Answer 14

fermentation releases SCFA’s, decreasing cell proliferation

binds and speed excretion of dietary carcinogens and toxins

Question 15

Name 2 hydrophilic vitamins an their functions

Answer 15

B - enzyme cofactors

C - protein synthesis

Question 16

Name 4 lipophilic vitamins and their functions

Answer 16

A - development
D - calcium metabolism
E - antioxidant immune function
K - blood clotting