INDULGING in a midnight snack could wreak havoc with your
memory, experts have warned.
Those who typically eat late at night can experience trouble
recalling information and learning.
Gorging on food at times typically reserved for sleeping
increases the risk of altering the brain’s physiology to
trigger deficiencies in learning and memory, they found.
The study was published in eLife.
These changes occur in the hippocampal area of the brain –
the area that’s linked to memory formation and storage, and
emotion.
Scientists from the University of California, Los Angeles
(UCLA), United States (U.S.) set out to investigate the
cognitive effects of eating at inappropriate hours.
It was already known that such eating habits could have an
impact on metabolic health – and lead to a pre-diabetic
state.
Dr. Dawn Loh, of the UCLA Laboratory of Circadian and Sleep
Medicine, said: “We have provided the first evidence that
taking regular meals at the wrong time of day has far-
reaching effects for learning and memory.
“Since many people find themselves working or playing
during times when they’d normally be asleep, it is important
to know that this could dull some of the functions of the
brain.”
The researchers tested the ability of mice to recognize a
novel object. They found that mice fed during their sleep
time were significantly less able to recall the object. The
scientists also subjected the mice to a fear-conditioning
experiment. They found that the mice’s long-term memory
was also drastically reduced.
Both long-term memory and the ability to recognize a novel
object are governed by the hippocampus, the researchers
said.
The hippocampus also affects the ability to associate senses
and emotional experiences with memory – and our ability to
organize and store new memories. Nerve impulses are active
along specific pathways during an experience. If we repeat
the experience, the same pathways increase in strength.
But, that effect was lowered when food was made available to
mice during the six-hour window in which they normally sleep
– as opposed to a six-hour daytime window when the mice
were active.
Certain genes involved in both the circadian clock – and
learning and memory – are regulated by a cAMP response
element-binding protein (or, CREB protein).
If CREB is less active, it decreases memory – and plays a role
in the onset of Alzheimer’s disease.
The mice that were fed at the wrong time exhibited
significantly reduced activity in CRED throughout the
hippocampus.
But, the suprachiasmatic nucleus in the hypothalamus – which
is the ‘master pacemaker of the circadian system’ – was
unaffected.
That results in ‘desynchrony between the clocks in the
different brain regions (misalignment)’ – which suggests
memory impairment.
Dr. Christopher Colwell, of UCLA, said: “Modern schedules can
lead us to eat around the clock so it is important to
understand how the timing of food can impact cognition.
“For the first time, we have shown that simply adjusting the
time when food is made available alters the molecular clock in
the hippocampus and can alter the cognitive performance of
mice.”