Brain research finds new appetite- suppressing nutrient
21 January 2010
A vitamin-like nutrient called citicoline could be the next
weapon in the battle against the obesity epidemic in developed
countries.
Scientists at McLean Hospital and professors at Harvard Medical School
in the US have explored the effects of Cognizin citicoline
supplementation on the neurobiological systems involved in appetite and
eating behaviour regulation.
They found it has potential to reduce food cravings and increase
feelings of satiety. Their work was published in the January issue of
the International Journal of Eating Disorders.
Dr Deborah Yurgelun-Todd, then Associate Professor of Psychiatry at
Harvard Medical School and McLean Hospital, monitored the effect of
nutrients such as citicoline on the dopamine neurons in the brain, which
have been shown to have a direct effect on the motivation to eat and the
rewarding value of food.
She explains, "We know that appetitive responses are highly regulated
by homeostatic mechanisms in the hypothalamus portion of the brain,
including hormones and dopamine. Previous research has measured the
effect that hormones and dopamine — and nutrients like citicoline that
may increase these compounds — may have in a variety of substance abuse
and addictive behaviour disorders such as cocaine addiction and
pathological gambling. In this latest study, we applied a similar set of
theories to study citicoline and both regulation of food intake and
motivation to eat."
This study compared the effects of open label treatment with
citicoline at two different dosages (500 mg/day versus 2,000 mg/day) for
six weeks on changes in appetite ratings (using questionnaires), weight,
and brain response to images of high-calorie foods (using magnetic
resonance imaging).
In the stimulation phases of the study, at baseline and following the
6-week treatment, participants were monitored via MRI while viewing a
series of colourful visuals that included both high-calorie foods and
non-food objects in a quick 150-second series of photos. Each image was
viewed for a brief, three seconds. Study participants included 16
healthy adults (8 men, 8 women) ranging from 40 to 57 years of age, and
across a range of Body Mass Index values from 20 to 38.
Appetite ratings did decline significantly for the group as a whole,
as assessed by questionnaire responses. The decline for the high-dose
group did reach significance, however the low-dose group did not. There
was no significant weight change in weight for either group overall,
although individuals did show weight loss.
"The most interesting findings are that with the use of brain imaging
studies we are able to visualize the differences between baseline and
after 6-weeks of citicoline supplementation. Scans from the high-dose
group illustrate the shift in how their brains interpreted the food
images," explains Yurgelun-Todd, now the Director of the Cognitive
Neuroimaging Laboratory and The Brain Institute at the University of
Utah.
There are three regions of the brain that are particularly relevant
to appetite control and behavioural inhibition: the lateral
orbitofrontal cortex, the insular cortex and the amygdala. In a direct
correlation, those high-dose participants who had the greatest
activation of these three portions of the brain saw the greatest decline
in appetite for high-calorie foods.
"The citicoline may have affected their appetite by stimulating
regions of the brain used to normalize or regulate their response to the
food images. These three regions may help the participant see food as
less rewarding, and therefore have a lesser desire to eat it," added
Yurgelun-Todd.
Citicoline has a number of different mechanisms of action, and it has
yet to be determined which may be responsible for the changes in brain
responses.
The vitamin-like nutrient has been known to function as a precursor
of phospholipid and acetylcholine synthesis; citicoline also enhances of
the release of neurotransmitters such as norepinephrine and increased
synthesis of phospholipids including cardiolipin and sphingomyelin.
Citicoline has also been recognized for neuroprotective effects with
stroke or other brain injuries, protection from cognitive decline.
Though this research is still preliminary, researchers will continue to
investigate whether these effects are related to citicoline properties,
or from the effect citicoline has on the dopamine or other systems.