VITAMINS.pptx

VITAMINS
Dr PAUL TEMBO
BSc. HUMAN BIOLOGY (UNZA)
BSc. MEDICINE AND BACHELOR OF SURGERY (UNZA)

 Vitamin is the term used for a group of potent organic
compounds other than proteins, carbohydrates and
fats which occur in minute quantities in food and
which are essential for some specific body functions
such as regulations, maintenance, growth and
protection. Many of them cannot be synthesized, at
least in adequate amounts, by the body and must be
obtained from the diet
DEFINATION

 Vitamins are classified into:
 1)Fat- soluble vitamins and 2)water-soluble vitamins
 Fat-soluble vitamins: The fat soluble vitamins are
vitamins A, D, E and K. They require fat for their
absorption and can be stored in the body. If their
intake is poor, body stores are ample, deficiency
symptoms will not be seen immediately.
CLASSIFICATION OF VITAMINS:

 The water-soluble vitamins are B-complex vitamins
and vitamin C. Being water-soluble they are easily
absorbed and the excess consumed is excreted in the
urine. They are not stored in the body
Water-soluble vitamins:

 • No breakdown is required.
 • Mostly absorbed in small intestines.
 • Lipid soluble vitamins require presence of fats in diet
for absorption.
 • Water soluble vitamins are absorbed through diffusion.
 • Others depend on energy requiring transport, binding
with molecules or specific conditions in the gastro-intestinal
tract. eg- vitamin C is easily absorbed in the stomach while
vitamin B12 must be bound to protein produced in the
stomach.
ABSORPTION OF VITAMINS:

 • Most are bounded to protein and their delivery depends
on availability of protein carrier.
 • Water-soluble vitamins are absorbed through active and
passive transport and stored temporally in various tissues.
 • Fat-soluble vitamins are stored in tissues much longer.
 • Water-soluble vitamins are easily secreted and their
supplies are easily depleted than fat soluble ones can be stored
in liver and adipose tissue.
 • Water-soluble vitamins can easily be lost and deficiency
occurs.
ABSORPTION OF VITAMINS

 SOURCE: Food dietary sources are liver, milk, eggs,
milk products butter, cream etc, organ meats, oily
fish. Green leafy vegetables, yellow and red fruits and
vegetables like carrot, pumpkin, mango, papaya,
peaches, spinach, orange etc
VITAMIN A

 • Vitamin A maintains the normal vision in dim light.
 • It helps in synthesis and maintenance of healthy
epithelium – the outermost lining of the skin and
innermost lining of mucous membranes of respiratory,
gastro-intestinal and genitourinary tract.
 • Vitamin A is required for normal bone and tooth
development and proper growth.
 • It helps the body to fight against infections by
keeping mucous membranes in a healthy condition which
act as a barrier to infection
FUNCTIONS:

 If the body has sufficient stores, deficiency does not
develop at once.
 Primary deficiency: causes poor growth in children,
anaemia, vulnerability to infection, more likely to
become blind and children are more likely to die in
early childhood.
 Secondary deficiency: diet low in fat, protein or
mineral zinc. Vitamins cannot be absorbed without fat
and its delivery to tissues requires protein.
DEFICIENCY :

 1. Night blindness (nyctalopia):a condition where an individual is unable to
see well in dim-light, especially after coming from a brightly lit area.
 2. Epithelial changes: The epithelium becomes dry, scaly and rough.
 3. Changes in eyes are seen:
 • Secretion of tears decreases.
 • Eye ball becomes dry and lustreless.
 • Sensitivity to bright light is observed.
 • Cornea becomes dry and inflamed (xeropthalmia).
 • If xeropthalmia is untreated it leads to keratomalacia- softening of
the cornea and permanent blindness results.
 4. Bone development: Growth failure and stunted bones are seen in children
The diseases that can occur due to
lack of vitamin A:

 Hypervitaminosis A: high doses of vitamin A is not
recommended as excess is stored in the liver.
Excessive accumulation of vitamin A in the body is
toxic which leads to nausea, vomiting, abdominal
pain, loss of hair and joint pain.
Excess of vitamin A:

 An adult requires 600 µg of retinol or 2400 µg of β-
carotene per day: 4µg of β-carotene is converted to
1µg of retinol in the intestinal wall and liver
RECOMMENDED DAILY ALLOWANCE:

 • Vitamin D is stable and is not deteriorated by heat,
processing or storage for long periods.
 • Also known as sunshine vitamin.
 • It has been debated whether vitamin D is a hormone
or a vitamin. it is deemed as a hormone because it is
manufactured in the skin by exposure to sunlight while it
can also be a substance essential in the diet when
exposure is limited.
 • These two forms are called ergocalciferol which is
provided by the diet and cholecalciferol which is produced
by the skin in the presence of sunlight.
VITAMIN D (CHOLECALCIFEROL)

 1. Absorption of calcium and phosphorus from the
small intestine requires the presence of vitamin D and
the hormones of the parathyroid and thyroid gland.
 2. It helps in mineralization of bones and teeth
because after calcium and phosphorus is absorbed,
Vitamin D is required to ensure that these minerals
are deposited in bones and teeth to strengthen them.
 3. Regulation of calcium and phosphorus levels in
blood.
FUNCTIONS:

 Sunlight, fish liver oils, fortified milk, natural foods
such as butter, milk in small quantities.
SOURCES:

 Vitamin D deficiency causes mainly :
 1. Rickets and 2. Osteomalacia or osteoporosis
 1. Rickets: is a childhood disease usually caused by
inadequate vit-D and is characterised by Softening and
weakening of bones, causing bones to yield to pressure.It
is due to defective mineralisation of the Growth plate.
 Joints are enlarged and there is delayed closing of the
skull.
 Symptoms include: enlarged skull, pigeon chest, poor
muscle development, pot belly, bowed legs or knocked
knees.
DEFICIENCY:

 Osteomalacia is also a disorder of decreased mineralisation
arising usually from inadequate Vit-D ,but unlike Rickets ,it
results from defective mineralisation of the preformed
osteoporosis and occurs both in adults and children. It is
more common among women who consume a diet
deficient in calcium, phosphorus and vitamin D, and have
had several pregnancies.
 Symptoms include: softening of bones leading to
deformed spine, rheumatic pain in the legs and lower back
and spontaneous fractures
2. Osteomalacia or Osteoporosis:

 Large doses of vitamin D is toxic or can be toxic.
Excessive use of fortified foods lead to loss of
appetite, vomiting, diarrhoea, growth failure and
calcification of soft tissues and kidney stones.
 Recommended daily allowance: 200 IU
Excess of vitamin D or
Hypervitaminosis D:

 Tocopherol comes from a Greek word “Tos” meaning
“childbirth” and “phero” meaning “bring forth”.
 It is sensitive to destruction by oxygen, metals, light,
heat and some lost during processing, cooking and
storage.
VITAMIN E (TOCOFEROL)

 • The main function of vitamin E is to act as an
antioxidant. Vitamin E itself gets oxidized and protects cell
membranes from oxidative damage.
 • Prevents oxidation of vitamin A in the intestine.
 • Protects normal cell membranes by preventing their
breakdown.
 • Prevents haemolysis of red blood cells.
 • Cure for infertility.
 • Anti-scar medication.
 • Cancer.
 • Diabetes .
 • Defence against air pollution (protects the lung tissues
from damage by air pollution through nitrogen dioxide).
 • Anti-aging used in many creams and lotions
FUNCTIONS:

 1. Red cell membrane rupture leading to anaemia
(haemolytic anaemia).
 2. Neurological problems: muscular dystrophy and
paralysis.
 3. Foetal death and in males testicular changes and
sterility
VITAMIN E DEFICIENCY:

 • Vitamin toxicity is rare.
 • If vitamin E is consumed in excess it has an
antagonistic effect on the role of vitamin K in the
clotting mechanism.
 RECOMMENDED DAILY ALLOWANCE:
 8-10 mg is required for daily allowance
EXCESS OF VITAMIN E/ TOXICITY:

 It is derived from a Danish word “koagulation” which
means “blood clotting”. It is also called “koagulation
vitamin” because it is necessary for clotting or
coagulation of blood.
 It is found in many forms: phylloquinone (K1) is a form
found in plants, and menaquinone (K3) is a form
found in fish oils, and those that are synthesized by
bacteria (K2).
VITAMIN K (KOAGULATION)

 1. Required for the formation of prothrombin and
several other proteins involved in clotting of blood.
 2. The ability of blood to clot is dependent upon high
blood level of prothrombin, required to produce fibrin
a protein which forms structure of blood clot.
 3. Participates in the formation of calcium binding
proteins in the intestine.
FUNCTION:

 -Green leafy vegetables, cabbage, cauliflower,
broccoli, turnip green.
 - Cheese, egg yolk, tomato, milk, meat, eggs, cereals.
 -Rice, bran oil, wheat germ oil, soya bean and cotton
seed oils.
 60-80 µg is required for daily allowance.
SOURCES:

 The types of vitamin-B complex found are as follows:
 1. Thiamine (B1)
 2. Riboflavin (B2)
 3. Niacin (B3)
 4. Pantothenic acid (B5)
 5. Pyridoxine (B6)
 6. Biotin (B7)
 7. Folic acid
 8. Cyanocobalamin (B12)
B-COMPLEX VITAMINS:

 It Cannot be destroyed by cooking. The functions are
as follows:
 • It helps to maintain a healthy nervous system.
 • It is required for normal appetite and digestion.
 • Thiamine functions mainly as co-enzyme which is
required in the breakdown of glucose to yield energy
VITAMIN B1/ THIAMINE

 1. Foods rich in protein such as pork, liver, pulses,
groundnut, eggs.
 2. Whole grain and enriched cereals, parboiled rice,
unpolished rice and sprouted pulses.
SOURCES:

 • Characterized by anorexia which is an eating disorder characterized by
immoderate food restriction and irrational fear of gaining weight, as well as body weight
loss.
 • Beri-beri: inflammation of the nerves, numbness of extremities, muscle
weakness and cramps, with increase in rate of heart beat, inability to move, swelling etc.
 Dry Beri-beri; is thiamine deficiency with associated nervous system involvement.
Neurological findings include, peripheral neuropathy, wernicke encephalopathy (an
acute Neurological condition characterised by a triad of ophthalmoplagia, ataxia and
confusion. If untreated wernicke Encephalopathy can lead to a non reversible
neuropsychiatric disorder called Korsakoff Psychosis( characterised by configuration,
memory loss and gait abnormalities).
 Wet Beri-Beri; is associated with Cardiovascular involvement. Characterised by Periphery
vasodilation, salt and water retention, fluid overload hence Edema of extremities.
SHOSHIN BERI-BERI is a more rapid form of wet beriberi with predominant cardiac injury,
hence myocardial failure.

 RECOMMENDED DAILY INTAKE:
 0.5 mg/1000 kcal/day should.
DEFICIENCY:

 • Acts as a coenzyme, it is a vital factor in carbohydrate
metabolism and protein metabolism.
 • Form co-enzyme flavin mononucleotide (FMN) which
is needed in citric acid cycle and fat metabolism and flavin
adenine dinucleotide (FAD).
 • Both FMN and FAD is needed in electron transport
chain.
 Sources:
 • Milk and cheese, organ meats, eggs, poultry etc.
 • Dark green leafy vegetables and enriched cereal
foods.
RIBOFLAVIN (VITAMIN B2)

 • Swelling of lips and cheilosis.
 • Cracks in the skin at the corners of the lip.
 • Redness and swelling of the tongue.
 • Eyes look blood shot, eye fatigue, itching,
burning, watering and sensitivity to bright light, i.e.
photophobia.
 • Sore throat, rash, purple tongue, cracks in the
mouth
Deficiency:

 0.55 mg/1000 kilocalories per day should be taken.
 TOXICITY:
 • Not known to be toxic.
 • Very high intake will result in bright yellow urine.

 • Coenzyme of nicotinamide adenine dinucleotide
(NADH) and nicotinamide adenine dinucleotide
phosphate involved in the metabolism and release of
energy of carbohydrates, fatty acids and amino acids.
 • Involved in energy metabolism.
 • For a healthy skin, normal gastrointestinal tract
and maintenance of the nervous system.
NIACIN (VITAMIN B3)

 • Protein rich foods such as poultry, fish, meat,
groundnut, beans and peas are good sources.
 It is difficult to determine because it can be synthesized
from amino acid tryptophan but approximately 60 mg of
tryptophan is needed to make 1mg of niacin.
 RDA is set at 6.6 NE per 1000 kilocalories and not less than
13 NE’s for 2000 kilocalories.
 However needs are increased in pregnancy and lactation
SOURCES:

 • Deficiency results in pellagra characterised by four
D’s- diarrhoea, dermatitis, dementia and death.
 • It begins with weakness, headache, loss of appetite
and weight and a sore and swollen tongue.
 • Dermatitis is symmetrical and on exposed parts of
the body- forearms, legs and hand is aggravated by
sunlight.
 • Dementia or depression, confusion, poor memory
and hallucinations occur severe deficiency.
 • If pellagra is not treated leads to death
DEFICIENCY:

 • High doses of niacin leads to lower blood
cholesterol concentration.
 • It may cause side effects of histamine release
that cause flushing and be harmful to those with
asthma or peptic ulcer diseases.
 • May be toxic to the liver.
TOXICITY:

 It is derived from a Greek word “panthos” which
means everywhere, because it is widely distributed in
food.
PANTOTHENIC ACID (VITAMIN B5)

 • It forms a complex compound coenzyme A (CoA) and
acyl carrier protein and thus it takes part in the metabolism
of carbohydrates and fats.
 • It is also necessary for the formation of acetylcholine,
which is a precursor of heme, (steroid hormone) which in
turn is essential for haemoglobin synthesis.
 • CoA is also essential for the synthesis of cholesterol
and sterols.
 • In our body pantothenic acid is present in the liver,
adrenal glands, kidneys, brain and heart.
FUNCTIONS:

 • Present in dried yeast, liver, rice polishing and
wheat germs are the rich sources.
 • Whole cereals, legumes, nuts, fleshy foods, eggs
and fish are fair sources.
 • Lean beef, sweet potato, skimmed milk and
molasses are fair sources.
SOURCES:

 • These are rare.
 • Observed in severely malnourished humans and
chronic alcoholics.
 • Loss of appetite, fatigue, weakness, headache,
insomnia, nausea, emotional instability, dizziness,
burning sensation in the feet, depression etc.
 TOXICITY:
 Massive doses produce mild intestinal diarrhoea
 NO RECOMMENDED DAILY INTAKE
DEFICIENCY OF PANTOTHENIC ACID:

 It is a white crystalline, odourless substance available in
water.
 FUNCTIONS:
 • Activate more than 50 enzymes involved in
metabolism of carbohydrates, fats and protein.
 • Needed in synthesizing haemoglobin and white blood
cells.
 • Needed for some neurotransmitter.
 • Can cure carpel tunnel disease which is associated
with repetitive and forceful movements of the hand and
wrist during work or leisure activities.
PYRIDOXINE (VITAMIN B6)

 • Chicken, fish, pork and organ meats.
 • Whole wheat, soya bean, sunflower seed.
 • Banana, broccoli, spinach, pulses, cabbage etc.
 0.016 mg per gram of dietary protein
SOURCES:

 • Weakness, irritability and insomnia.
 • Consuming formulas by infants that has lost
vitamin B6 through heating can cause abdominal
distress, convulsions and other neurological
symptoms.
 • Other symptoms are poor growth, skin lesions,
decreased anti-body formation and anaemia may
occur.
DEFICIENCY:

 Occurs when more than 2 gm of it is taken daily and
symptoms include depression, irritability, nerve
damage causing muscle weakness leading to inability
to walk and bone pain
TOXICITY:

 It was named vitamin H or Haunt which means skin.
 FUNCTION:
 • Biotin plays an important role in maintaining the
skin structure and for the health of the nervous
system.
 • It functions in energy production via citric acid
cycle and in glucose synthesis via gluconeogenesis.
BIOTIN ( VITAMIN B7)

 • Rice polishing, mushrooms, groundnut, soya
bean, whole cereal, legumes and fleshy foods.
 • Liver, kidney, egg yolk, nuts, oat meals.
 • Banana , grape fruit etc.
SOURCES:

 Not calculated because some of the requirement is met by
absorption of biotin produced by bacteria in the gastrointestinal
tract.
 DEFICIENCY OF BIOTIN:
 • Produced by a protein present in egg white called avidin
which causes dermatitis muscular in-coordination and spasticity
of legs and loss of hair.
 • Its deficiency is rare.
 • Muscle pain, anorexia, nausea, anaemia are some of the
symtoms.
 TOXICITY:
 No known toxic effects even in large doses

 Derives its name from Latin word “Folium” which
means leaf. It has been known to prevent anaemia in
pregnant women.
 Folate is unstable and can be destroyed by
processing, storage and preparation.
FOLATE (FOLIC ACID)

 • Folate has a role in DNA synthesis and is important
during periods of rapid growth such as early embryonic life
and in intestines and skin where cells are rapidly dividing.
 • Essential for formation of red and white blood cells in
the bone marrow.
 • Folate acts as an enzyme co-substrate in synthesis
reactions in metabolism of amino acids and nucleotides by
donating or accepting single carbon units.
FUNCTIONS:

 • Liver, kidney, yeast, milk .
 • Green leafy vegetables, fruits, mustard leaf,
broccoli.
 • Whole pulses, corn, wheat, legumes etc.
 -RDA of 3µg per kilogram of body weight per day.
 -RDA for pregnant women is set at 400µg per day.
SOURCES:

 • Symptoms include weakness, loss of weight.
 • It results in megaloblastic anaemia which is common
in underdeveloped countries, among the vulnerable age
group, where there is failure for blood cells to divide but
grow big.
 • Associated with birth defects that effect the brain
and spinal cord a condition known as neural tube defects.
 • Immune suppression leading to frequent infections
DEFICIENCY:

 • No adverse effects recorded.
 • High intake may mask the early symptoms of
vitamin B12 deficiency allowing irreversible nerve
damage to occur.
TOXICITY:

 Vitamin B12 are cobalt containing compounds.
 • Can only be made by bacteria, fungi, algae .
 • Closely related to folate and depends on each
other for activation.
 • Vitamin B12 is bound to protein in food and must
be cleaved by pepsin in stomach.
COBALAMIN (VITAMIN B12)

 • Needed for synthesis of RNA and DNA.
 • The most important function is the production of
nucleic acids and in cell division.
 • Helps in folate metabolism.
 • Necessary for nerve transmission
FUNCTIONS:

 • Organ meats like kidney, liver, brain.
 • Meat, poultry, egg, fish and milk are good sources of
vitamin B12.
 • It is produced in the large intestine by bacteria but
cannot be absorbed by the human body.
 - Normal person = 1 microgram/day
 - Pregnant women = 1.5 microgram/day
 - Infants and children = 0.2 microgram/day
SOURCE:

 • It causes pernicious anaemia- the life span of red blood cells is
reduced to 60 days instead of the normal 120 days and their size and shape
also changes.
 • Skin colour changes, it shows yellow pallor.
 • Soreness and shine on the tongue, are the manifestations of skin
lesions.
 • Nervous tissues are degenerated, especially the posterior column of
the spinal cord is affected.
 • Some other symptoms are tingling, numbness, loss of sensation in
the limbs, exaggerated knee jerks and ankle jerks.
 • Depression and gastrointestinal disease.
 TOXICITY:
 None known so far.
DEFICIENCY:

 • Vitamin C is destroyed by cooking and because of being water
soluble it is easily discarded in cooking water.
 FUNCTIONS:
 • Acts as an anti-oxidant.
 • Aids in collagen formation.
 • Disease prevention.
 • Resistance to infection.
 • Regenerate the fat soluble fat anti-oxidant vitamin- E.
 • Prevention of oral, oesophageal and stomach cancer
(research).
 • Cataract and heart diseases can be prevented using the anti-
oxidant properties of vitamin-C.
VITAMIN C (ASCORBIC ACID)

 • Vegetables, pepper, tomatoes, lettuce,
potatoes, cauliflower.
 • Fruites, papaya, orange, mangoes etc.
 - Adults=100 mg
 - Pregnant women = 300 mg
 - Children not known
SOURCES:

 • Acute results in scurvy- impaired wound healing,
oedema, haemorrhages and weakness in bones, cartilage
and connective tissue.
 • It can develop in infants fed on formulas not enriched
with vitamin C.
 • Adults with scurvy may have swollen bleeding gum
and eventually teeth loss, rheumatic pain in the legs and
skin lesions and various psychological changes.
 • People who do not eat enough vitamin C may not
absorb iron and may develop iron deficiency called
anaemia.
DEFICIENCY:

 • None so far.
 • Only adverse effects of high doses are
gastrointestinal disturbance and diarrhoea.
 • Over doses may also increase the risk of renal
stones.
 • Others are nausea, headache, fatigue and
insomnia.
TOXICITY:

 Excess amounts of water-soluble vitamins are
generally removed by urine excretion, while the fat-
soluble vitamins by biliary Excretion.
ROUTE OF EXCRETION

THANK YOU FOR LISTENING
KNOWLLEDGE IS POTENTIAL, BUT THE APPLICATION
OF KNOWLEDGE IS POWER.
THE END

REMEMBER THAT LIFE IS ABOUT VISION!
MAKE YO PASSION BE YO PROFFESION
COG14 QUIZ 1
1)Draw the structure for the Glycerol Molecule.
2)List 9 Essential Amino Acid.
3)State the Difference between Amylopectin and
Amylose and State the chemical Bonds involved in
each.

 ASSIGNMENT -1
1)Briefly Discuss the 4 Protein Structural levels and give
examples of each.
2)Using a table, Compare And Contrast :
a) Heteropolysaccharides and Homopolisaccharides.
b)Glycogen and Starch.
3)Discuss BMI; Definition, Formula and Ranges.

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