WEEK 4: Carbs and Health

Question 1

Describe how glucose is stored as glycolysis

Answer 1

• after a meal BGL rises, liver cells link excess glucose molecules by condensation into long,branching glycogen chains
• BGL falls, liver cells break glycogen by hydrolysis into single molecules of glucose + release them to bloodstream.
  -glucose becomes available to supply energy to brain/other tissues regardless of whether the person has eaten recently
• Muscle cells can store glucose as glycogen (the other two-thirds), but using it for themselves during exercise.
• the brain maintains a small amount of glycogen=provide an emergency energy reserve during times of severe glucose deprivation

Question 2

Describe how glucose is used for energy

Answer 2

• inside cells, enzymes break glucose in half
  -halves can be put back together to make glucose or can be further broken down into smaller fragments (never again to be reassembled to form glucose)
  -fragments can yield energy when broken down completely to co2 and h20
• liver’s glycogen stores last only for hours, not days, must keep
  providing glucose to meet the body’s energy needs
• a person needs to eat dietary carbohydrate frequently.

Question 2

Describe how glucose is made from protein

Answer 2

• Glucose is the preferred energy source for brain cells, other nerve cells+ developing red blood cells.
• Body protein can be converted to glucose but protein has a number of tasks that no other nutrient can do.
• Body fat cannot be converted to glucose
• a person does not replenish depleted glycogen stores by eating carbs=proteins are broken down to make glucose to fuel these special cells-> gluconeogenesis

Question 3

Why is important to maintain glucose homeostasis and how is it regualted

Answer 3

• body must maintain bgl within limits that permit cells to nourish themselves
  -BGL below normal= person may become dizzy and weak
  -BGL above normal=a person may become fatigued
• BGL regulated by insulin(moving glucose from blood to cells)
• and glucagon(brings glucose out of storage)

Question 4

What happens when BGL falls

Answer 4

occurs between meals
- Alpha cells of the pancreas secrete glucagon in response to low blood glucose
- Glucagon signal the liver to break down its glycogen stores and release glucose into the blood for use by all the other body cells.
- When a person experiences stress, adrenaline acts quickly, ensuring that all the body cells have energy fuel in emergencies
- adrenaline works to release glucose from liver

Question 5

What happens when BGL rises

Answer 5

• beta cells in pancreas respond by secretin insulin into blood
• amt of insulin secereted corresponds to rise in glucose
• insulin contacts receptors on other cells responds by storing glucose into cells
  -cells take only the glucose they can use for energy right away
  -liver and muscle cells can assemble the small glucose units into long, branching chains of glycogen for storage
• liver cells can also convert glucose to fat for export to other cells
• excess glucose is stored as glycogen and fat.

Question 6

How to balance BGL within the normal range

Answer 6

balanced meals at trg intervals
that provide abundant complex carbs
- including dietary fibre and a little fat, help slow down the digestion and absorption of carbohydrate so that glucose enters the blood gradually, providing a steady, ongoing supply

Question 7

What two conditions are a result of BGL falling outside normal range

Answer 7

Diabetes and hypoglycaemia

Question 8

What happens to BGL during diabetes

Answer 8

• BGL rises after a meal and remains above normal lvls
• bc insulin is either inadequate or ineffective.
• BGL is central to diabetes, but dietary carbohydrates do not cause diabetes.

Question 9

Describe type 1 diabetes, symptoms

Answer 9

• less common type
• pancreas fails to produce insulin
• thirsty and increased needs to go to toilet
• hunger
• weight loss

Question 10

Why do T1D symptoms occur

Answer 10

• no glucose enters the cells->causing hunger->excessive eating
• cells break down protein+fat->weightloss-> excessive eating

Question 11

Describe type 2 diabetes, symptoms

Answer 11

• common type of diabetes,
• cells fail to respond to insulin.
• condition tends to occur as a consequence of obesity.
• weight gain

Question 12

Why do T2D occur

Answer 12

• some glucose enters the cells slowly
• leading to hunger-> excessive eating-> weight gain

Question 13

How to manage T2D

Answer 13

• Eating balanced meals, regularly
• glycaemic response key

Question 14

Describe hypoglycaemia, symptoms

Answer 14

BGL rises after eating-> gradually falls back into the normal range
- BGL below normal=person would experience the symptoms of hypoglycaemia: weakness, rapid heartbeat, sweating, anxiety, hunger and trembling.
-hypoglycaemia is a consequence
of poorly managed diabetes
- Too much insulin, strenuous physical activity, inadequate food intake or illness can cause blood glucose levels to fall
-rare in healthy ppl

Question 15

How do treat hypoglycaemia

Answer 15

• need only adjust their diets by replacing refined carbohydrates with carbohydrates rich in dietary fibre and ensuring an adequate protein intake
• smaller meals eaten more frequently may help.

Question 16

What is the glycaemic response

Answer 16

The impact of foods consumed on blood glucose concentrations
- low absorption,modest rise in blood glucose, smooth return to normal are desirable=low glycaemic response.
- Fast absorption, surge in blood glucose,overreaction that plunges glucose below normal are less desirable=high glycaemic response
- Diff foods have different effects on BGL

Question 17

Benefits of the of low GI -> low bgl

Answer 17

• commonly used to assist individuals with diabetes
• ensures foods chosen provide a sustained release of energy
• greater satiety
• reduces hyperglycaemic episode+ insulin requirements.

Question 18

What is considered a low, intermediate, high GI

Answer 18

What is low?
* ≤55
– What is Intermediate?
* 55-70
What is high?
* ≥≥70

Question 19

What factors influence a high Gi

Answer 19

• Starch structure (high amylopectin) eg. basmatic rice < jasmine
• processing(popping, flaking) eg corn on cob<popcorn

Question 20

What factors influence a low Gi

Answer 20

• Lactose in milk eg. Milk < cordial
• Fructose in fruit eg Apple < lollies
• fat eg. Butter and bread < bread alone
• fibre eg. Grain bread < white/brown bread

Question 21

Equation for glycaemic load

Answer 21

• (grams CHO per serve x GI)/ 100

Question 22

Benefits of the of high GI -> high bgl

Answer 22

• Increase hyperglycemic episodes
• Useful for treating hypos

Question 23

What are the health effects of sugar

Answer 23

• Excessive intakes may displace nutrients and contribute to obesity
• Dental carries/tooth decay
• obesity/diabetes
• Naturally occurring sugars from fruits, vegetables and milk are acceptable sources

Question 24

Why isnt some natrually ocurring sugars healthy

Answer 24

- Honey contains glucose and fructose. - in table sugar the two monosaccharides are bonded together as a disaccharide, whereas in honey some of them are free. - they end up the same way in the body: as glucose and fructose. -Honey is denser than crystalline sugar, too, so it provides more energy per spoonful. - fruit has same amount of energy as a spoonful of sugar or honey, but the packaging is more valuable nutritionally. - sugars (Fruit) arrive in the body diluted in a large volume of water, packaged in dietary fibre and mixed with essential vitamins, minerals and phytochemicals.

Question 25

3 types of alternative sweetners and examples

Answer 25

- Artificial( 0Kj) -> saccharin, sucralose, aspartame -Natural -> Stevia, oligosaccarides - sugar alcohols ->mannitol, sorbitol, xylitol

Question 26

Describe sugar alcohols

Answer 26

- Occur naturally - found in Biscuits, lollies, gums, jams - ‘Sugar-free’ (but not kJ free) - Excess consumption – laxative effect - No dental caries