Micronutrients: Vitamins and Minerals

What are micronutrients?

Substances required in small amounts for normal metabolism but cannot be synthesized by the body in sufficient quantity

What are the different vitamins?

A B C D E K

Which vitamins are fat soluble?

A D E K

Which vitamins are water soluble?

Bs and C

What does vit a deficiency cause?

impaired night vision

What does vit d deficiency cause?

Impaired calcium absorption and bone mineralization

What does vit c deficiency cause?

breakdown of connective tissue (scurvy)

What does vit b12 deficiency cause?

megaloblastic aneamia

What does vitamin K deficiency cause?

haemorinagic diseases

What are sources for vit a?

dairy

liver

Sources for vit b1?

whole cereals

nuts

seeds

Sources for vit b2?

Liver

dairy

Sources for vit b3?

meat

wholemeal cereals

Sources for vit b6?

liver

cereals

fruit and veg

Sources for vit b12?

meat

fish

dairy

Sources for vit c?

fruit and veg

Sources for vit d?

sunlight

dairy

oily fish

Sources for vit E?

green leafy veg

Sources for vit K?

liver

green leafy veg

Sources for folic acid?

liver

green leafy veg

whole grain cereals

What is the RNI for vit a?

600-700 ug per day

How is vit d formed?

Formed in skin by action of UV light on 7-dehydrocholesterol

pre cursor of calcitrol

produced in kidney

stimulates gene synthesis of ca2+ binding protein to increase ca2+ absorption from GIT - enhances Ca2+ reabsorption from kidney

Where do we obtain most vit d from?

>90% from sunlight, rest from oily fish, egg yolk

How much sunlight needed to produce sufficient vitamin D?

20-30 mins on face and forearms at midday

2-3 times per week generates enough vit d

darker skin and elderly need increased exposure

What is the safe intake of vit e?

3-4mg a day

antioxidant, prevents damage to phospholipids

What is the safe intake of vit k?

1 ug /kg per day

required for post translational modification of prothrombin and clotting factors

What is the RNI for Vit b12?

1.5 ug/day

What is the RNI for folic acid?

200 ug per day

What is the RNI for thiamine?

1mg per day

deficient can cause adverse effects on sensory and motor nerves resulting in muscle wasting and paralysis

What is the RNI for nicotinic acid?

17 mg per day

Deficiency can cause diarrhoea, dementia

risk factors are alcohol and poor diet

What is the RNI for vitamin c?

40mg per day

How does scurvy occur?

vit c is an antioxidant required for proline hydroxylase, converts proline to hydroxy proline which is required for collagen

What are the symptoms of scurvy?

Bleeding gyms, loose teeth, leaky blood vessels, impaired wound headling

all caused by the impaired synthesis of collagen

What is the RNI for calcium?

700mg pure day

What is calcium needed for?

bones

cell signaling

muscle function

What is the RNI for iron?

male 8.7 mg per day

female 14.7mg per day

What is the role of iron?

Component of haemoglobin, myoglobin, and enzymes

Absorption - active transport in small intestine

vitamin c absorption

calcium and tea inhibit absorption

What are the limits for vitamins?

vit a - no safe upper limit

vit b6 - 10mg a day

zing - 25mg per day

b carotene - 7mg a day