4 - Micronutrients: Vitamins and Minerals

Question 1

What are the two basic types of vitamins?

Answer 1

Water soluble (B-complex, C)
Fat soluble (D, E, K, A)

Question 2

What are the properties of water soluble (B-complex, C) vitamins?

Answer 2

Can be deficient in weeks to months if not consumed (lost with water)
Only B12 can be stored
Niacin, choline and C can cause ill effects in excess

Question 3

What are the properties of fat soluble (D, E, K, A) vitamins?

Answer 3

Stored in body fat, liver, other parts of body.
Deficiencies take longer to develop
Excess can build up and lead to toxicity

Question 4

What are the key roles of Vitamin A in the body?

Answer 4

Cell growth and vision

Question 5

Vitamin A:

Retinyl esters found in animal foods are converted to retinol. What does retinol do?

Answer 5

Retinol supports reproduction

Retinol can be converted into retinal and vice versa
Retinal can be converted into retinoic acid

Question 6

Vitamin A:

Beta-carotine found in plant foods can be converted into retinal. What does retinal do?

Answer 6

Participates in vision

Retinal can be converted into retinol and vice versa
Retinal can be converted into retinoic acid

Question 7

Vitamin A:

Retinal can be converted into retinoic acid. What does retinoic acid do?

Answer 7

Regulates growth

Retinal can be converted into retinol and vice versa

Question 8

What are the effects of vitamin A deficiency?

Answer 8

Decreased cell division and deficient cell development

Night blindness
Impaired immunity
Reproductive and growth abnormalities
Exhaustion
Death

Question 9

What are the effects of vitamin A toxicity?

Answer 9

Overstimulated cell division

Skin rashes
Hair loss
Hemorrhages
Bone abnormalities
Birth defects
Fractures
Liver failure
Death

Question 10

What colour can excess beta-carotene turn your skin?

Answer 10

Yellow

Question 11

What is the main source of vitamin D?

Answer 11

Skin exposure to direct sunlight (~10-15 mins of sunlight exposure, blocked by suntan lotions)

Question 12

What are the functions of vitamin D?

Answer 12

Helps absorption of calcium and phosphorus
Maintains bone integrity
Maintains nerve and muscle activity

Question 13

What are the consequences of vitamin D deficiency and toxicity?

Answer 13

Deficiency:
Rickets

Toxicity:
Deposition of calcium in organs
Mental retardation in young children
Abnormal bone growth and formation

Question 14

What are the functions of vitamin C?

Answer 14

Connective tissues (manufacture collagen)
Antioxidant
Helps fight infection, repair wounds
Enhance iron absorption

Question 15

What are the effects of vitamin C deficiency and toxicity?

Answer 15

Deficiency:
Scurvy

Toxicity:
>1g per day
Nausea, cramps, diarrhoea

Question 16

What is the DRI for vitamin C?

Answer 16

Men - 90mg
Women - 75mg

Smoking men - 125mg
Smoking women - 110mg

Question 17

What is calcium needed for?

Answer 17

Bone strength
Muscle contraction
Nerve signals
Blood clotting

Question 18

How does bone density change with age?

Answer 18

Bone density peaks between 20-30
Women lose 30-40% bone density by 70
Rate of loss determined by peak bone density, diet, lifestyle behaviours

Question 19

How is bone density built and maintained?

Answer 19

Adequate calcium and vitamin D, ideally before age 30

Question 20

What is the function of iron?

Answer 20

It is present in haemoglobin (red blood cells) and myoglobin (muscle cells)

Question 21

Which is more readily absorbed, heme iron or nonheme iron?

Answer 21

Heme iron. It is found in meat, fish, poultry

Meanwhile iron from plants is nonheme iron

Question 22

What are the effects of iron deficiency and toxicity?

Answer 22

Deficiency:
Anemia

Toxicity:
Damage liver, pancreas, heart
Excess iron is not easily excreted