vitamines.ppt

VITAMIN E
The term vitamin E describes a family
of 8 antioxidants,
4 tocopherols (a,b, g, & d) and
4 tocotrienols.
a-tocopherol is the active form of
vitamin E in the human body.

FUNCTIONS
• The main function of vitamin E is anti
oxidant. It intercepts free radicals &
prevents destruction of cell membrane.
• It protects the fat in LDL from oxidation.
• It inhibits platelets aggregation.
• It enhances vasodilatation.
• It inhibits the activity of protein kinase C.

Vitamin E Dietary Sources
 Vegetable oils
 Almonds & peanuts
 Avocado
 Spinach
 Carrots (least)

Vitamin E deficiency
•Severe vitamin E deficiency causes:
Neurological symptoms (impaired
coordination) & muscle weakness.
Increased risk of cardiovascular
diseases
Hemolytic anemia in children

RISK FACTORS
Severe PEM
Genetics defects affecting the
transfer protein of a-tocopherol
 Fat malabsorption syndrome

THERAPEUTIC USES
 Prevention of cardiovascular diseases
 Diabetes Mellitus
 Cancer prevention
 Boost immunity
 Dementia

TOXICITY
Excess vitamin E may cause:
 Impaired blood clotting leading to
increased risk of bleeding in some persons.
It is recommended that vitamin E
supplements to be stopped one month
before elective surgery.

VITAMIN K
The K is derived from the German word
Koagulation.
There are 2 naturally occurring forms of
vitamin K. Plants synthesize phylloquinone
(vitamin K1) & bacteria synthesize
menaquinone-3 (vit K2).
Menaquinone-4 is produced in animals from
vit K1, but its function is yet to be discovered.

FUNCTIONS
•Vitamin K is needed for production of
vitamin K-dependent coagulation factors in
the liver.
•Other functions include:
Assist in bone mineralization. The
mineral binding capacity of osteocalcin
requires vit K.
Gas6 is vit K-dependent protein
identified in 1993. It is important for
neuronal function.

SOURCES OF VITAMIN K
Bacteria in large intestine produce vit
K2 and supply 40-50% of human
requirement.
Vegetable oils
Almonds & peanuts
Avocado & Broccoli
Spinach, Lettuce, parsley (raw)

Vitamin K deficiency
 Is uncommon in adults. Only those with
severe liver disease & those on oral
anticoagulants are at risk.
 Exclusively breast fed & premature babies
are at risk coz human milk is low in vitamin E
& their gut is not yet colonized with bacteria.
 Hemorrhagic disease of the newborn is a
serious threat to life & routine vit k
prophylaxis is recommended by the AAP.

VITAMIN C
 Humans, unlike other mammals, are
unable to make ascorbic acid & they get it
from food.
 Rich dietary sources are citrus juices
(orange, grapefruit & lime), strawberry,
Guava, tomato, sweet red pepper & broccoli.
 Recommended daily intake is between
15-120 mg/day depending on age. Smokers
& lactating mother needs the higher range.

FUNCTIONS
 Collagen synthesis
 Antioxidant
 Synthesize of noradrenaline
 Carnitine synthesize
 Metabolism of cholesterol to bile salts

Vitamin C deficiency
 Severe deficiency leads to Scurvy with the
following manifestations:
Bleeding & bruising easily
Hair & teeth loss
Joint pain & swelling
Fatigue & lack of concentration

THERAPEUTIC USES
• Cardiovascular diseases
• Cataracts
• Diabetes Mellitus
• Cancer prevention
• Common cold
• Lead toxicity

DRUG INTERACTIONS
• Contraceptive pills & aspirin lower
vitamin C level in plasma & WBC.
• Vitamin C in large dose blocks the action
of warfarin & interferes with
interpretation of certain lab tests
(bilirubin & creatinine in serum and
guaiac assay for occult blood).
• Previous claims of serious toxic effects
of vit C are not evidence-based.

VITAMIN B Complex
 Group of 7 water soluble vitamins, thiamin,
riboflavin, niacin, pyridoxine, cobalamin,
biotin & pantothenic acid.
 Biotin & pantothenic acid deficiencies are
extremely rare coz it is found in numerous
foods and also is synthesized by intestinal
bacteria.
 Biotin deficiency may occur with prolonged
antibiotic therapy & ingestion of raw eggs.

THIAMIN (VIT B1)
 Thiamin is rapidly converted to its active
form, thiamin pyrophosphate in the brain and
liver by a specific enzymes, thiamin
diphosphotransferase.
 TPP is necessary as a cofactor for the
reactions of the pentose phosphate pathway.
 The dietary requirement for thiamin is
proportional to the caloric intake of the diet
and ranges from 1.0 - 1.5 mg/day for normal
adults.

RISK OF THIAMIN DEFICIENCY
 Low intake & alcoholism
 Increased consumption: Malaria & AIDS
 Excessive loss: hemodialysis and diuretics
 Anti-thiamin factors: tea & coffee.
 Thiaminases found in raw fish, raw shellfish
& in silkworms.

DEFICIENCY & USES
 Severe thiamin deficiency can lead to:
 Beri-Beri
 Wernicke-Korsakoff syndrome
 Thiamin is used for treatment of
congestive heart failure & Alzheimer's
disease as well as in cancer prevention.

RIBOFLAVIN (VIT B2)
 Adequate amounts of B2 is present in eggs,
milk, meat & cereals. Deficiency is often seen
in chronic alcoholics due to their poor dietetic
habits.
 Symptoms associated with riboflavin
deficiency include, glossitis, seborrhea,
angular stomatitis, cheilosis and photophobia.
 Riboflavin decomposes when exposed to
visible light. This characteristic can lead to
riboflavin deficiencies in newborns treated by
phototherapy.

NIACIN (VIT B3)
 Niacin is available in both animal & plant
food and is made in the body from
tryptophane.
 Severe deficiency causes pellagra with
glossitis, dermatitis, diarrhea, depression and
dementia.
 Hartnup disease, malignant carcinoid
syndrome & Isoniazid can lead to niacin
deficiency .
 In large doses niacin lowers plasma
cholesterol but it elevates blood glucose &
uric acid levels, so it is not recommended
with diabetes & gout.

PYRIDOXINE (VIT B6)
 Pyridoxine functions as a cofactor in
enzymes reactions required for the
synthesis & catabolism of the amino acids
as well as in glycogenolysis.
 Widely available in diet & deficiency
may follow INH & pencillamine therapy.
 Deficiency can cause neonatal seizures,
cheilosis, glossitis & neuroitis.

COBALOMIN (VIT B12)
 B12 functions as a cofactor for enzymes
required for the catabolism of fatty acids &
the conversion of homocysteine to
methionine.
 B12 is not available in plant & deficiency
may occur in strict vegetarians & in pts
with GIT problems & those on prolonged
antibiotic treatment.
 Deficiency causes megaloblastic
anemia, SACDC, & high homocysteine in
blood which is a risk of IHD & stroke.

FOLIC ACID
 Folic acid is obtained from yeasts and leafy
vegetables as well as animal liver. Animals can’t
synthesize folate, thus, it must come from diet.
 Folate is needed for synthesis of nucleic
acids
 Deficiency causes megaloblastic anemia &
neural tube defects in utero.
 Used for treatment of chronic hemolytic
anemia.

vitamines.ppt

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vitamines.ppt