Lecture 16

Question 1

What is the RDI for Calcium?

Answer 1

1000mg per day

Question 2

Do New Zealanders reach the RDI for Calcium?

Answer 2

Men are close, but women tend to consume less than required

Question 3

What are the main sources of calcium in NZ?

Answer 3

1. Milk
2. Bread
3. Cheese

Question 4

What percentage of Calcium is absorbed from the diet?

Answer 4

Approx 25-30%

Question 5

What can influence Calcium absorption?

Answer 5

Psychological and dietary factors

Question 6

What is bioavailability?

Answer 6

The proportion of a nutrient that is absorbed, utilised and thus available to the body

Question 7

Is the content of Calcium entirely bioavailbable?

Answer 7

No

Question 8

What are promotors of Calcium uptake?

Answer 8

• Protein and amino acids
• Lactose
• Acidic gut

Question 9

What are inhibitors of Calcium uptake?

Answer 9

• Oxalate
• Phosphorus
• Phyate

Question 10

Can calcium be stored?

Answer 10

No, the bones act as a reservoir

Question 11

What nutrient can calcium be considered as?

Answer 11

A threshold nutrient, you can’t grow more than your genes permit

Question 12

What is the main excretion route for Calcium?

Answer 12

Via ruine

Question 13

What factors can increase Ca excretion?

Answer 13

An increase in:

1. Protein
2. Sodium
3. Caffine

Question 14

What factors can decrease Ca excretion?

Answer 14

1. Bicarbonate
2. Phosphorus
3. Citrate

Question 15

What is the percentage break down of Calcium binding

Answer 15

47% bound to proteins
47% are free or ionised
6% are bound to anions

Question 16

What are the functions of Calcium?

Answer 16

• Intracellular messenger = <1% of body Ca
• Bone = 99% of Ca
• > structural role = skeleton
• > physiological role = reservoir of essential minerals

Question 17

What are the two types of bone?

Answer 17

1. Cortical

2. Trabecular

Question 18

Describe Cortical bone

Answer 18

• Compact/dense
• Slow turn over
• 80% of bone mass

Question 19

Describe Trabecular bone

Answer 19

• Spongy
• Is what will be broken down when body needs it
• 20% of bone mass

Question 20

What does bone remodelling allow?

Answer 20

• Maintains bone integrity

- Reshapes bone to accomodate changing mechanical loads

Question 21

What are the three bone cells?

Answer 21

1. Osteoblasts = build bone
2. Osteoclasts = break down bone
3. Osteocytes = ‘sensors’

Question 22

What is resorption?

Answer 22

Removal of old bone

Question 23

What is formation?

Answer 23

Replacement with new bone

Question 24

What is peak bone mass defined as?

Answer 24

The maximum bone mass

Question 25

What are the determinants of peak bone mass?

Answer 25

- Genetics - Environment (modifiable) - >exercise, smoking, medication, nutrition

Question 26

What happens to children and adults with Calcium deficiency?

Answer 26

- Children = have decreased growth and decreased bone mass | - Adults = have decreased bone mass

Question 27

What is a bone healthy diet?

Answer 27

-Dairy (or a fortified alternative) -Moderate protein -Low sodium (similar to DASH diet)