What is Melatonin?
Melatonin
is a hormone produced by the pineal
gland, which plays a
vital role
in the regulation of various
hormones according to the natural daily
cycles.
It
has a far-reaching biological influence
over most of the autonomic, hormonal
and
behavioural processes in the human body.
It
helps to regulate body
temperature,
influences female reproductive hormones
and cardiovascular
function. It
functions as a potent antioxidant and
enhances the immune system
by
stimulating natural killer cells.
Melatonin is
produced in abundance before
puberty,
but declines steadily after then until
old age, when virtually none is
produced.
Melatonin’s
diurnal rhythm is synchronised by the
light dark cycle and is strongly
affected
by day length, artificial lighting,
electromagnetic energy and exercise.
Hence, the longer the length of night, the
longer the duration of melatonin
secretion.
The exposure of light to
the retina alters the amount of serotonin
metabolised to
Melatonin, via the neural
pathways that connect the retina to the
pineal gland, thus
exposure to sufficient
levels of light at night can rapidly
reduce Melatonin production.
Consequently melatonin levels should be
low during the day and high at night,
peaking at about 2-3 a.m.
Excesses
and deficiencies of melatonin are equally
important and may relate to
physical and
psychological symptoms. Abnormalities of
melatonin have been
closely
linked to a variety of behavioural
changes and mood disorders including;
insomnia,
sleep-wake problems, mood
disturbance, increase risk of
cardiovascular disease,
immune
dysfunction, inhibition of ovulation, low
body temperature, even cancer.
