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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
MACalvey/Teachnet/Vitamins 2006 5
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
MACalvey/Teachnet/Vitamins 2006 6
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
MACalvey/Teachnet/Vitamins 2006 7
Vitamin B1 - Thiamine
SourcesMeat and offal
Oatmeal, breakfast cereals
Wheatgerm
Fortified white flour
Milk
Eggs
Vegetables
MACalvey/Teachnet/Vitamins 2006 8
Vitamin B1 - Thiamine
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
MACalvey/Teachnet/Vitamins 2006 9
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
MACalvey/Teachnet/Vitamins 2006 10
Vitamin B2 -Riboflavin
Sources
Offal
Milk
Cheese
Eggs
Yeast extracts
Green Vegetables
MACalvey/Teachnet/Vitamins 2006 11
Vitamin B2 -Riboflavin
Properties
• Water soluble
• Unstable at high temperatures
• Destroyed by alkalis
• Light sensitive
RDA
1 - 1.5 mg per day
MACalvey/Teachnet/Vitamins 2006 12
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
MACalvey/Teachnet/Vitamins 2006 13
Vitamin B -Niacin (Nicotinic acid)
Sources
Meat, Offal
Yeast extracts
Yeast
Bran, wheatgerm, flour
Some pulses, dried fruit
MACalvey/Teachnet/Vitamins 2006 14
Properties
• Water soluble
• Stable to heat
• Fairly stable to acids/alkalis
• 80 -90% loss in milling
*RDA
15 - 20mg per day
Vitamin B -Niacin (Nicotinic acid)
*Related to protein intake
MACalvey/Teachnet/Vitamins 2006 15
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
MACalvey/Teachnet/Vitamins 2006 16
Vitamin B6 -Pyridoxine
Sources
Meat
Offal
Eggs
Yeast extracts
Fish
Cereals
MACalvey/Teachnet/Vitamins 2006 17
Properties
• Water soluble
• Reasonably heat stable
• Sensitive to high temperatures, oxygen, milling and processing
RDA
2mg per day
Vitamin B6 -Pyridoxine
MACalvey/Teachnet/Vitamins 2006 18
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
MACalvey/Teachnet/Vitamins 2006 19
Vitamin B12 - (Cyano) Cobalamin
Sources
Meat, Offal
Fish
Cheese
No B12 in plant foods - Vegans, vegetarians risk of deficiency
MACalvey/Teachnet/Vitamins 2006 20
Properties
• Water soluble
• Heat stable up to 100°C
• Affected by strong acids/alkalis
• Affected by light
RDA
3-4 µg per day
Vitamin B12 - (Cyano) Cobalamin
MACalvey/Teachnet/Vitamins 2006 21
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
MACalvey/Teachnet/Vitamins 2006 22
Vitamin B -Folic Acid
Sources
Offal
Fortified cereals
Green leafy vegetables
Potatoes
bread
Milk
Wheatgerm
MACalvey/Teachnet/Vitamins 2006 23
Properties
• Water soluble
• Unaffected by acids
• Sensitive to light and oxidation
RDA
300 µg per day
More during
pregnancy
Vitamin B -Folic Acid
MACalvey/Teachnet/Vitamins 2006 24
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
MACalvey/Teachnet/Vitamins 2006 25
Vitamin C -Ascorbic Acid
Sources
Rosehips, blackcurrants,
green peppers, kiwi, citrus
fruits, strawberries,
spinach, cabbage,
broccolli
MACalvey/Teachnet/Vitamins 2006 26
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
Vitamin C -Ascorbic Acid
Least stable of all vitamins
Recommended