Types

Retinol

Carotene (provitamin)

Classification

Fat soluble

Functions

- Needed to form pigment rhodopsin
- Needed for health of epithelial tissues, skin and membranes
- Needed for healthy skin
- Needed for optimum growth

Properties

- Insoluble in water
- Soluble in fats
- Fairly stable to heat
- Destroyed by oxidation
- Drying causes serious loss

Sources

liver
fish liver oils
herrings
butter
margarine
egg yolks

carrots
dark green vegetables
spinach
peas
cabbage
apricots

RDA

- Children: 300-750mg
- Adults: 750mg
- Pregnant women and nursing mothers: 750-1200mg

Deficiency

- Night blindness
- Damage to mucous membranes
- Dry and scaly skin
- Xerophthalmia (eye disease) common in Third World
- Retarded growth

Types

Ergocalciferol - produced by light

cholecalciferol - dehydrocholesterol is produced by sunlight

Classification

Fat soluble

Functions

- Absorption of calcium and phosphorous
- Builds bones and teeth

Properties

- Insoluble in water
- Soluble in fats
- Not destroyed by heat or oxidation
- Resistant to acids and alkalis

RDA

- Children: 10mg
- Adults: 2.5mg
- Pregnant women and nursing mothers: 10mg

Deficiency

- Osteomalaria (depletion of calcium and phosphorous). Can occur during pregnancy, when mothers are breastfeeding and in old age
- Poor teeth development
- Rickets: a childhood disease due to non-absorption of calcium and phosphorous

Classification

Fat soluble

Functions

- Anti-oxidant
- Improves fertility (in rats)

Sources

Oils and margarines
Whole grains
Liver
Fruit and vegetables

RDA

None, as the vitamin is widely available in many foods

Deficiency

Is rare

Classification

Fat soluble

Functions

Formation of prothrombin for blood clotting

Properties

- Stable to heat, air and moisture
- Not resistant to light
- Cooking destroys a little

Sources

- Green leafy vegetables, e.g., lettuce, spinach, cabbage
- Egg yolk
- Liver
- Synthesised by bacteria in the intestine

RDA

Deficiency is rare

Deficiency
(rare)

- Haemorrhaging under skin- Internal bleeding

Classification

Water soluble

Functions

- Necessary to form collagen
- Promotes healing
- Maintains strength in blood vessels
- Helps absorption of iron
- Protects against infection

Properties

- Most unstable of all vitamins
- Destroyed by oxidation.This is accelerated by bruising, chopping and drying.
- Water soluble
- Food value lost in storage
- Destroyed by heat
- Destroyed by alkali

Sources

Strawberries
Citrus fruits
Melon
Rose-hip syrup
Milk
Green leafy vegetables, e.g., cabbage, broccoli and brussel sprouts

RDA

- Children and adolescents: 40-60mg per day
- Adults: 60mg per day
- Nursing mothers: 80-100mg per day

Deficiency

- Degeneration of body tissues, skin and teeth
- Retarded growth
- Pains in limbs and swollen joints
- Listlessness, restlessness and irritability
- Delay in healing
- Scurvy
- Anaemia

Example

Thiamine B1

Riboflavin B2

Functions

- Releases energy from food
- Promotes growth
- Prevents beri-beri

- Aids metabolism of energy foods
- Promotes welfare of the body

Properties

- Lost in preservation and cooking
- Water soluble
- Destroyed by alkali, dry heat and milling

- Lost during cooking and canning
- Water soluble
- Destroyed by alkalis and sunlight

Sources

Wholegrains
Pulse vegetables
Nuts
Pork
Liver, Heart, Kidneys

Liver
Milk, cheese, eggs
Meat
Dried yeast

RDA

1-1.5 mg per day

1.2 -1.7mg per day

Deficiency

- Beri-beri
- Poor appetite
- Slow growth
- Muscle cramps

- Skin abnormalities
- Poor vision
- Slow growth