Why does too much cheese make you have vivid dreams?
Cheese is a rich source of neuroactive compounds including the
monoamine called "tyramine", which has provokes the release of
adrenaline.
When we go to sleep a small part of the brainstem, called the
locus coeruleus, switches on and through its connections with other
regions of the brain triggers rem (rapid eye movement) sleep, which
is associated with dreaming.
The name locus coeruleus is latin for "blue place" and if you
cut across the brainstem with a knife you can clearly see the
blue-coloured nerve cells that comprise this region. The cells are
pigmented by neuromelanin, the neurological equivalent of a suntan.
Neuromelanin is made as a biproduct in the synthesis of the nerve
transmitters noradrenaline (a relative of adrenaline) and dopamine.
These chemicals are derived from tyrosine, the same stuff used to
make melanin in skin cells.
So the locus coeruleus, which triggers dream-sleep, uses
noradrenaline as its nerve transmitter. Since cheese contains
tyramine, which has the ability to potentiate the action of
adrenline-like nerve transmitters, it is likely that eating cheese
before bed fools the brain into thinking that there is more
adrenaline waashing around than normal, making dreams more
vivid.
Famously, when some of the first antidepressants were invented
they worked by blocking the breakdown of monoamine / indolamine
nerve transmitters including dopamine, noradrenaline and serotonin
by inhibiting an enzyme called MAO (monoamine oxidase). But when
patients on these drugs ate cheese it could provoke periods of
life-threateningly high blood pressure and a racing heart rate,
through the uncontrolled release of adrenaline as there was no MAO
to breakdown the tyramine in the diet.
