Vitamin C: Why we need it, dietary sources, and how we absorb and metabolize it

Vitamin C: Why we need it, dietary sources, and how we absorb and metabolize it

January 7, 2020 4 By Ewald Bahringer


hey everyone this lesson is on vitamin C
so and this is we’re going to talk about where we can get vitamin C from our diet
we’re gonna also talk about the metabolic processes we need vibin C for
including catecholamine biosynthesis and other processes as well we’re also going
to talk about what happens when we actually ingest vitamin C and how we
absorb it and excrete it from our body so vitamin C is also known as ascorbic
acid it is an essential water-soluble vitamin it’s required for several
processes one of those is acting as a reducing agent in collagen synthesis
another one is acting as a cofactor for enzymes in the carnitine biosynthesis
pathway and another one is acting as a cofactor for enzymes in the
catecholamine synthesis pathway we’re going to talk in more detail in the next
slide about these each of these processes so we get vitamin C from our
diet and vitamin C is found in citrus fruits and various vegetables so we can
remember citrus fruits with a C for vitamin C so citrus fruits like oranges
mangoes those types of fruits but we can also get it in tomatoes and strawberries
and we can also get it in from vegetables like potatoes Brussels
sprouts and broccoli so again think of those citrus fruits and if we don’t get
enough vitamin C if we have a vitamin C deficiency this causes the condition
known as scurvy so what do we need vitamin C we talked about those few
processes before where vitamin C is required vitamin C is required in
collagen synthesis process of collagen synthesis uses iron and actually
oxidizes iron from ferrous to ferric so Fe 2 plus 2 Fe 3 plus through a
hydroxylation reaction and vitamin C actually acts as a reducing agent so it
reduces fe 3 plus 2 Fe 2 plus so ferric back to ferrous ion now vitamin C is
also used in catecholamines synthesis so in the process of catecholamines
synthesis when we have dopamine and dopamine becomes acted on by the enzyme
dopamine beta hydroxylase that enzyme dopamine beta hydroxylase actually
requires vitamin C so that is why we need vitamin C in catecholamine
synthesis to produce Noora and the third process where vitamin C’s
required is carnitine biosynthesis carnitine biosynthesis there’s actually
a couple of enzymes the first enzyme in the pathway requires vitamin C so the
conversion of tri methyl lysine to 3 hydroxy and trimethyllysine by the
enzyme trimethyllysine hydroxylase requires vitamin C and iron Fe 2 plus in
the last enzyme in the pathway converting gamma beuter o betaine to L
carnitine by the enzyme gamma beuter o betaine hydroxylase also requires
vitamin c and fe 2 plus as well so the first in the last enzymes in the
carnitine biosynthesis pathway required vitamin C 2 so if you haven’t checked my
catecholamine synthesis or carnitine biosynthesis lessons please check those
out as well if you want more details on these pathways so these are where
vitamin C is required for our body where we need it
collagen synthesis catecholamine synthesis and carnitine biosynthesis so
how do we absorb and metabolize vitamin C vitamin C’s again taken in our diet
and it is a water-soluble vitamin so it can be ingested but it has to be
actively absorbed within the small intestine it’s not a lipid soluble
vitamin so it’s absorbed in the small intestines any excess that is not
absorbed in the small intestines is actually degraded in the intestines
there is a process of reversible oxidation to what we call the hydro
ascorbic acid the hydros korvac acid is also an active form as well and if we
take up too much if we absorb too much vitamin C the vitamin C is actually
essentially is excreted in our urine when the blood levels of ascorbic acid
are highs so generally the number is roughly greater than 80 milligrams per
day so again if we have greater than 80 milligrams per day of vitamin C our
blood levels of ascorbic acid rise and if it hits a sort
threshold we generally excreted in the urine so if you’re essentially taking a
lot of vitamin C supplements you are going to activate that process and is
simply excreted in your urine so you’re really not using it at all but again we
need a certain amount so this is how we absorb metabolized and excreted so this
is the basic process of vitamin C absorption in metabolism vitamin C is
actively absorbed in the small intestines if it’s not absorbed it gets
degraded in the intestines there is a threshold of blood levels of ascorbic
acid generally they say around greater than 80 milligrams per day of ascorbic
acid is gonna hit that threshold and once you pass that threshold you’re
essentially going to excrete whatever’s past that threshold out in the urine so
that is the general process of vitamin C absorption metabolism and distribution
within our body so now that we know where we can get vitamin C in her diet
why we need vitamin C and how we absorb it and metabolize it we’re gonna talk
about what happens when we don’t have enough vitamin C in our diet so vitamin
C deficiency so we’re gonna talk about that in the next lesson so if you
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though for more lessons like this one and thank you so much for watching and I
hope to see you next time