Minerals

Question 1

Functions of calcium

Answer 1

1. Contraction and relaxation of muscle, especially important for heart muscle
2. Formation of strong bones and teeth
3. Transmission of nerve impulses

Question 2

Importance of maintaining a constant calcium level in the blood:

Answer 2

1. Heart is not able to contract properly
2. Calcium is taken from the bones to maintain high enough blood calcium levels for heart

Question 3

food sources of calcium

Answer 3

Vegetarian sources: Milk and milk products (35% is absorbed)
Animal sources: Fish with small bones eg sardines
Plant sources:
— Tofu (soy bean curd)
— Almonds, sesame seeds
— Dark green vegetables (eg. Broccoli and bok choy) and seaweed (nori)…….absorption varies from 5-60%

Question 4

What is calcium absorption increased by

Answer 4

Salmon
Tuna
Margarine
Butter
Fortified milk
Fortified cereals

Question 5

What is calcium absorption decreased by

Answer 5

Caffiene

Question 6

Why do post menopausal women require more calcium

Answer 6

Post menopausal women require more calcium because estrogen decreases after memopaise. This can cause osteoclasts and lead to osteoporosis making bones weaker and more brittle.

Question 7

Why do elderly men and women (70+ years) require more calcium

Answer 7

Aging is associated with a gradual loss of bone mass, and therefore they need to consume more calcium
Calcium is leeched from their bones

Question 8

describe two reasons why people who eat a mainly plant based diet may be at higher risk of having lower bone density.

Answer 8

They have to get calcium from non dairy sources
Lower levels of calcium in plant based foods
More vitamin D in plant based foods

Question 9

Suggest two strategies that people following a mainly plant based diet can use to improve bone density.

Answer 9

Don’t drink coffee
Take supplements
Get lots of vitamin D

Question 10

functions of iron

Answer 10

Forms part of haemoglobin which carries oxygen around the body (red blood cells)
Forms part of mitochondria in muscles, which makes oxygen available for muscle contraction

Question 11

dietary sources of haem iron

Answer 11

red meat, kangaroo, fish, pork, egg yolk, liver

Question 12

Absorption rates of harm iron

Answer 12

Up to 25%
Generally unaffected by other dietary factors

Question 13

Dietary sources of non-haem iron

Answer 13

dark green leafy veg, fortified Weetbix, all bran,

Question 14

Absorbtion rate of non-haem iron

Answer 14

10-17%
Decreased by calcium, caffeine
Increased by haem iron, vitamin C

Question 15

who needs more iron

Answer 15

people following a vegetarian diet
Women in reproductive years
Anorexia
Extreme diets
Developing countries

Question 16

1. Describe two differences between haem and non-haem iron.

Answer 16

Haem is found in animal sources, non haem is found in plant sources
Haem is bound to proteins, non haem is not bound to proteins

Question 17

Describe two different reasons why someone may have iron deficiency.

Answer 17

Not consuming enough iron
Pregnancy

Question 18

Functions of sodium

Answer 18

Helps to control water balance in body à regulates blood pressure
Helps control muscle contraction and relaxation

Question 19

food sources of sodium

Answer 19

— Salt either added during preparation, cooking or just before eating
Processed foods and snack foods (flavour enhancer + preservative)

Question 20

what does sodium deficiency cause

Answer 20

Muscle cramps, vomiting and apathy (can’t be bothered)
Not common in Australia but high levels of physical activity in intense heat can result in deficiency in the short term