A, C, E, D, B, K.

No, this isn't some random,
out of order alphabet.

These are vitamins,
and just like letters build words,

they're the building blocks
that keep the body running.

Vitamins are organic compounds we need
to ingest in small amounts

to keep functioning.

They're the body's builders, defenders
and maintenance workers,

helping it to build muscle and bone,
make use of nutrients,

capture and use energy
and heal wounds.

If you need convincing about
vitamin value,

just consider the plight of 
olden day sailors,

who had no access to vitamin-rich
fresh produce.

They got scurvy.

But vitamin C,
abundant in fruits and vegetables,

was the simple antidote to this disease.

While bacteria, fungi and plants
produce their own vitamins,

our bodies can't, so we have to get
them from other sources.

So how does the body get
vitamins from out there into here?

That's dependent on the form
these compounds take.

Vitamins come in two types:

lipid-soluble and 
water-soluble,

and the difference between them 
determines how the body

transports and stores vitamins, 
and gets rid of the excess.

The water-solubles are vitamin C

and B Complex vitamins that are made up of
eight different types

that each do something unique.

These are dissolved in the watery parts
of fruits, vegetables and grains,

meaning their passage through the body
is relatively straightforward.

Once inside the system,
these foods are digested

and the vitamins within them are
taken up directly by the bloodstream.

Because blood plasma is water-based,

water-soluble vitamins C and B have their
transport cut out for them

and can move around freely 
within the body.

For lipid-soluble vitamins,
dissolved in fat

and found in foods like diary,
butter and oils,

this trip into the blood is a little
more adventurous.

These vitamins make it through
the stomach and the intestine,

where an acidic substance
called bile flows in from the liver,

breaking up the fat and preparing it for
absorption through the intestinal wall.

Because fat-soluble vitamins can't make
use of the blood's watery nature,

they need something else 
to move them around,

and that comes from proteins that attach
to the vitamins and act like couriers,

transporting fat-solubles into the blood
and around the body.

So, this difference between water-
or fat-soluble vitamins

determines how they get into the blood,

but also how they're stored 
or rejected from the body.

The system's ability to circulate
water-soluble vitamins

in the bloodstream so easily

means that most of them can be passed
out equally easily via the kidneys.

Because of that, 
most water-soluble vitamins

need to be replenished on a daily basis
through the food we eat.

But fat-soluble vitamins have
staying power

because they can be packed into the liver
and in fat cells.

The body treats these parts like a pantry,

storing the vitamins there and rationing
them out when needed,

meaning we shouldn't overload
on this type of vitamin

because the body is generally 
well stocked.

Once we figured the logistics
of transport and storage,

the vitamins are left to do the work
they came here to do in the first place.

Some, like many of the B Complex vitamins,
make up coenzymes,

whose job it is to help enzymes 
release the energy from food.

Other B vitamins then help the body
to use that energy.

From vitamin C, you get the ability to
fight infection and make collagen,

a kind of tissue that forms 
bones and teeth and heals wounds.

Vitamin A helps make white blood cells,
key in the body's defense,

helps shape bones and improves vision 
by keeping the cells of the eye in check.

Vitamin D gathers calcium and phosphorus 
so we can make bones,

and vitamin E works as an antioxidant,

getting rid of elements in the body
that can damage cells.

Finally, from Vitamin K, we score
the ability to clot blood,

since it helps make the proteins
that do this job.

Without this vitamin variety,

humans face deficiencies that 
cause a range of problems,

like fatigue, nerve damage, 
heart disorders,

or diseases like rickets and scurvy.

On the other hand, too much of any
vitamin can cause toxicity in the body,

so there goes the myth that loading
yourself with supplements is a great idea.

In reality, it's all about getting the
balance right,

and hitting that vitamin jackpot.