Vitamins are the most
essential organic compounds that does not produced in human body but the
required amount are important for the proper functioning of the body systems.
Vitamins consist of two words “vita” means “life” and “amins” means
“necessary”. So vitamins can be defined as the organic compounds which are
required and necessary to lead a healthy life style.
DATS (DIGESTION, ABSORPTION,
TRANSPORTATION AND STORAGE) OF VITAMIN-C
Vitamins are classified into two types:
Fat soluble vitamins (A, D, E, K)
Water soluble vitamins (B, C)
Fat soluble vitamins are
that type of vitamins which are only soluble in fats and are in soluble in
water. Fat soluble vitamins include A, D, E and K. the deficiencies of these
vitamins are very rare as these vitamins does not easily excrete out of the
body and store these vitamins. All fat soluble vitamins are considered as
functionally different but are common in structure. the amount of fats in human
body effects the absorption of fat soluble vitamins i.e. if the concentration
of fats is less than 10-15 % than these vitamins does not absorb in human body.
Water Soluble
Vitamins are that type of vitamins that can be easily soluble in water and
does not retain inhuman body except vitamin B12. The deficiencies of these
vitamins are rapid and causes no toxicity because these vitamins Water can
easily get out of the body through urine. These vitamins include B complex and
C vitamins. All water soluble Vitamins are structurally different but mostly
have a common same function i-e it acts as some co-enzymes that assist in body
chemical reactions.
VITAMIN-C (ASCORBIC ACID):
Human beings are the mammals that are not able to
synthesized ascorbic acid. This is because humans lack the last enzyme gulono
lactone oxidase which are responsible for Vitamin C production. Vitamin C is a
six carbon compound. This vitamin was first time developed when the problem referred
to as scurvy was has been prevailing for centuries. The British sailors who
often died from scurvy on sea voyages. Szent-Gyorgyi discovered vitamin and
Haworth determined its structure.
Sources:
The best sources of vitamin C are:
sources |
Amount of Vitamin C in 100 grams |
Asparagus |
5.6mg |
Orange juice |
50mg |
oranges |
53.2mg |
broccoli |
89mcg |
Green pepper |
80.4mg |
lemons |
53mg |
Cantaloupe, citrus fruits, cauliflower, papaya, Brussels
sprouts, grapes, kale, strawberries are also the best sources of Vitamin C.
Supplements supply Vitamin C as a free Ascorbic Acid
(calcium ascorbate, sodium ascorbate and ascorbyl ascorbate.
RDA (recommended dietary
allowances):
The recommended dietary allowances of vitamin C are
different for the people at different life stages. RDA of vitamin C for Men,
Women and Children are:
Gender |
RDA |
Men |
60mg |
Women |
60mg |
Children |
45mg |
Functions of vitamin C in Human
body:
Vitamin C performs most of the important functions in human
body these are:
It helps in wound healing and repairing.
Protect body from scurvy.
It is critical for immune system.
Acts as an anti-oxidant and helps in maintenance of
cholesterols.
Helps in iron absorption.
Formation of connective tissues like collagen.
DATS (digestion, absorption,
transportation and storage) of vitamin C:
Vitamin C does not require digestion prior to its absorption
in intestinal cells.
Absorption of ascorbate occurs throughout the small
intestine. For its absorption ascorbate first oxidized to Dehydro ascorbate by
removing its two electrons and two protons. This Dehydro ascorbate absorbed by
using sodium dependent transporters. In addition to absorption sodium ascorbate
may also compete with GLUT transporters and especially GLUT1 and GLUT3
transporters which are responsible for the transportation of glucose into the
blood. This is the reason that large amount of glucose may also diminished the
absorption of vitamin C in the blood. Anion channel in some cells may also
mediate vitamin C absorption faster. Yet after absorption into the blood capillaries
it is transported towards the tissue cells where it is immediately reduced back
into ascorbic acid. The reducing agents are dehydro ascorbate reductase,
glutathione and NADPH. Unabsorbed vitamin C may be metabolized by intestinal
flora.
After absorption now the vitamin C are transported towards
different body tissues. For the transportation of vitamin C at least two
transporters are present i-e SVCT1 and SVCT2 (sodium ascorbate co transporters)
for vitamin uptake into most of the organs. SVCT1 is found in most epithelial
tissues and are appear to have higher capacity for vitamin C transportation
than SVCT2.
As vitamin C is a water soluble vitamin so it does not store
in body. Its regular consumption through diet are required so that the person
will not feel any deficiency. The highest amount of it are present in adrenal
and pituitary gland,. Intermediate amount are found in liver, kidney, spleen,
heart, lungs, pancrease and leucocytes. While the lowest amount are found in
red blood cells.
Interaction of Vitamin C with other
nutrients:
The interaction of vitamin C are mainly found with two
minerals Iron and Copper.
Vitamin C not only effects the absorption of non heme iron
in human body but also effects its distribution. As the amount of vitamin found
to assist the rapid absorption of non heme iron in human body.
However, in response to copper the highest concentration of
vitamin C decreases the serum copper concentration.
Toxicity:
Daily intake of up to 2 g of vitamin C does not have any
adverse effect in human body. But above this dose can may cause adverse effect.
The adverse effect of this vitamin include gastrointestinal problems
characterizes by abdominal pain and diarrhea. The unabsorbed vitamin C in the
intestinal tract are metabolized by the intestinal bacteria within the colon
and this is what it promotes diarrhea. Based on this the tolerable upper limit
for vitamin C are 2g per day.
Scurvy (disease caused by Vitamin C
deficiency):
Scurvy is the disease caused by vitamin C deficiency in diet
for at least 3 months. Scurvy is characterized by bleeding gums, loosened teeth,
sores formation and old wounds may reopen. Scurvy may also lead to death if not
treated earlier. It can be treated by having the proper amount of vitamin C
containing foods like fruits and vegetables.
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