Course: Nutrition and Metabolism - National University soluble... · 2019-04-04 · MACalvey/Teachnet/Vitamins 2006 26 Properties •Water soluble •Destroyed by alkalis, dry or

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Course: Nutrition and Metabolism

Part (4): Vitamins

Lecture (1): Water Soluble Vitamins (1)

Dr. Nuha AminMobile: +249910050800

WATER SOLUBLE VITAMINS

Vitamins B and C

• Functions

• Effects of deficiency

• Sources

• Properties

• RDA

M.A.Calvey/Vitamins 2006 3

VITAMINS

• “VITAMIN” means “vital for life”

• VITAMINS are *Micronutrients

which are necessary for everyday healthy functioning of the body

* Nutrientsrequired in very small amounts -mg or µg

MACalvey/Teachnet/Vitamins 2006 4

VITAMINS -Two main categories

Water soluble

B

C

Fat Soluble

A

D

E

K


Water soluble

• Cannot be stored in body - regular supply needed

• Excess is excreted in urine - no danger of toxic levels

• Unstable to heat and light, leach into cooking liquids

Fat Soluble

• Can be stored in body -regular supply not needed

• Can accumulate to toxic levels if large amounts ingested

• Fairly stable at normal cooking temperatures


Vitamin B1 - Thiamine

Functions

• Essential for release of

energy from

carbohydrates

• Necessary for appetite

and good health

• Needed for normal

functioning of nervous

system

Deficiency

• Fatigue, depression, irritability

• Beri-beri - disease of nervous system

Common in countries where polished rice is staple food



SourcesMeat and offal

Oatmeal, breakfast cereals

Wheatgerm

Fortified white flour

Milk

Eggs

Vegetables



Properties

• Water soluble

• Destroyed by high temperatures

• Destroyed by alkalis

• Lost by milling flour, leaching into cooking liquids and in thawing frozen food

RDA

1mg per day -

Requirement increases with energy expenditure


Vitamin B2 -Riboflavin

Functions

• Metabolism of carbohydrates,

proteins and fats

• Growth, repair, development of

body tissues - healthy skin, eyes

and tongue

• The principal growth promoting factor in the vitamin B complex

Deficiency

• Loss of appetite

• Swollen tongue, cracked lips, eye infection, dermatitis



Sources

Offal

Milk

Cheese

Eggs

Yeast extracts

Green Vegetables



Properties

• Water soluble

• Unstable at high temperatures

• Destroyed by alkalis

• Light sensitive

RDA

1 - 1.5 mg per day


Vitamin B -Niacin (Nicotinic acid)

Functions

• Metabolism of

carbohydrates, proteins

and fats

• Needed for normal

functioning of nervous

system

Deficiency

• Fatigue, depression, irritability

• Beri-beri - disease of nervous system

Common in countries where polished rice is staple food



Sources

Meat, Offal

Yeast extracts

Yeast

Bran, wheatgerm, flour

Some pulses, dried fruit


Properties

• Water soluble

• Stable to heat

• Fairly stable to acids/alkalis

• 80 -90% loss in milling

*RDA

15 - 20mg per day


*Related to protein intake


Vitamin B6 -Pyridoxine

Functions

• Protein metabolism

• Involved in formation of

haemoglobin, hormones and

structural proteins

• Healthy development of

nervous system

Deficiency

• Tiredness and Fatigue, irritability

• Premenstrual tension

• Infants may suffer convulsions if there is deficiency



Sources

Meat

Offal

Eggs

Yeast extracts

Fish

Cereals


Properties

• Water soluble

• Reasonably heat stable

• Sensitive to high temperatures, oxygen, milling and processing

RDA

2mg per day



Vitamin B12 - (Cyano) Cobalamin

Functions

• Red blood cell formation

• Nervous system -

maintains myelin sheath

around nerves

• Helps treat pernicious

anaemia

Deficiency

• Pernicious anaemia

• Nerve degeneration



Sources

Meat, Offal

Fish

Cheese

No B12 in plant foods - Vegans, vegetarians risk of deficiency


Properties

• Water soluble

• Heat stable up to 100°C

• Affected by strong acids/alkalis

• Affected by light

RDA

3-4 µg per day



Vitamin B -Folic AcidFunctions

• Red blood cell formation

• Essential for synthesis of

DNA and RNA

• Development of brain, spinal

cord and skeleton in foetus

• Reduces risk of neural tube defects e.g. spina bifida

• May play role preventing heart attacks, strokes and cancer

Deficiency

• Fatigue in mild cases

• Anaemia in severe cases

• Neural tube defects

Important to take folic acid prior to conception and vital during first 3 months pregnancy


Vitamin B -Folic Acid

Sources

Offal

Fortified cereals

Green leafy vegetables

Potatoes

bread

Milk

Wheatgerm


Properties

• Water soluble

• Unaffected by acids

• Sensitive to light and oxidation

RDA

300 µg per day

More during

pregnancy

Vitamin B -Folic Acid


Vitamin C -Ascorbic Acid

Functions

• Formation of connective tissue, collagen

• Critical to immune system

• Helps absorption of iron

• Prevents scurvy

• Promotes healing of wounds and healthy blood vessels

• Acts as antioxidant, protects HDL cholesterol

Deficiency

• Weakening of connective tissue

• Susceptibility to infection

• Incomplete iron absorption

• Delayed healing of wounds



Sources

Rosehips, blackcurrants,

green peppers, kiwi, citrus

fruits, strawberries,

spinach, cabbage,

broccolli


Properties

• Water soluble

• Destroyed by alkalis, dry or moist heat and enzymes

• Sensitive to light and oxygen

• Acts as an antioxidant

RDA

30-60 mg per day


Least stable of all vitamins

Documents

Course: Nutrition and Metabolism - National University soluble... · 2019-04-04 · MACalvey/Teachnet/Vitamins 2006 26 Properties •Water soluble •Destroyed by alkalis, dry or