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MICRONUTRIENTS
Vitamins:
• A group of organic compounds that have a
variety of functions in the body and that are
chemically different from each other.
•Vitamins can be “fat soluble” (A,D,E,K)* and
may be stored in the body and the remaining are
water soluble and can not be stored in the body.
Water soluble vitamins :
1- B-complex :
•B1= thiamin,
•B2=Riboflavin ,
•B3=Niacin,(nicotinic acid)
•B5=Pantothenic acid,
•B6=Pyridoxine,
•B7=Biotin ,
•B9=Folic acid,(folate)
•B12=Cobalamin ,
2- Vitamin C .
Vitamin C :
Ascorbic acid is absorbed in the distal small
intestine .
two forms :
•Reduced form (ascorbic Acid)
•Oxidized form (dehydro - ascorbic acid)
Stability in foods :1- It is very easily destroyed by heat, drying,
storage, alkalinity ( increased PH) .
2- Is very soluble in water, hence cooking
methods reduce or eliminate it .
Function :
•Water soluble antioxidant (extracellular):antioxidant
capabilities stabilize a number of other compounds,
including vitamin E and folic acid . Vitamin C and E are
free radical scavengers . Vitamin C reactivates oxidized
vitamin E for re-use . Protects the body against infection
and stress
•Collagen synthesis: it's essential for hydroxylation of
proline (precursor of collagen synthesis)
•Tyrosine catabolism .
•Enhances iron absorption : by reducing property of
vitamin C facilitates absorption of iron by reducing
Fe+++ to Fe++(divalent ferrous) and combining with it to
form soluble chelate so give vitamin C in treatment of
anemia
Sources :
Rich: Fresh citrus fruits
Important: fresh fruit, fresh and frozen vegetables .
Vitamin C deficiency
ascorbic acid deficiency occurs mostly in severely malnourished
individuals, drug, alcohol abusers, or those living in poverty. Human
deficiency of vitamin C lead to scurvy and lead to transient neonatal
hypertyrosinemia
Scurvy :
largely due to impaired collagen synthesis with disordered connective
tissue. Symptoms (ecchymoses, swollen and bleeding gums, Gum
becomes spongy, swollen, and purple
, petechiae, coiled hairs, hyperkeratosis, , arthralgias, and impaired
wound healing. weakness, malaise, joint swelling, arthralgias, edema,
depression,
In case of deficiency of vitamin C there is failure of hydroxylation of
proline and elastine and there will be disturbance of growing
basement membrane and intercellular cement substances and
connective tissue, these pathological features of scurvy .
Scurvy is a disease of sea-man as a result of deprivation of fresh fruits
and vegetables for few months .
Treatment :
Vitamin C tablet of 100mg/3 times daily will replenish a
depleted body pool in 5 days. Parenteral administration
of vitamin C is needed only if scurvy is so severe that
ability to consumption and absorption of oral dose of
vitamin C is doubtful. Replete body pool should be
maintain after treatment by ensurely that diet provide
daily recommended intake (40 – 60 mg/day ). Rebound
scurvy can occur when large doses or mega doses are
stopped
RDA : 60 mg per day for most adults; pregnant or
lactating women and the elderly have requirements up
to 125 mg/day.
Some people may need extra vitamin C:
•Pregnant/breastfeeding women
•Smokers
•People recovering from surgery
•Burn victims
•fever and infection,
•use of certain drugs (such as oral
contraceptives),
•environmental stress,