[Paleopsych] BH: Brain Molecule Guides Healthy Eating
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Thu Apr 14 13:59:21 UTC 2005
Brain Molecule Guides Healthy Eating
Ancient enzyme acts as an innate nutritionist to influence food choices
4/12/2005 3:42 PM
Burger and Fries
Credit: Greg Nicholas
Meal planner: An ancient enzyme in the brain appears to guide food
choices in omnivores to promote a balanced diet
If you're having trouble eating healthy, maybe you need to speak with
your internal nutritionist.
Mammals including humans appear to have such a nutritionist in the
form of an ancient brain molecule that regulates food choices.
The enzyme and its molecular mechanism are likely to be important
for all mammals that eat a varied diet comprising meat and vegetables,
Called GCN2 kinase, the enzyme initiates events relaying
information to the brain about foods' amino acid content.
This enables animals to adjust their food intake in favor of a more
Researchers have previously identified the molecular mechanism in
yeast and rats. David Ron of the New York University School of
Medicine and colleagues have now found it in mice, suggesting that
it's likely to be conserved in humans.
"This ancient pathway in mice recognizes drops in blood amino acid
levels that occur following consumption of food with an imbalanced
composition," says Ron. "That recognition culminates in a behavioral
response that limits consumption of the imbalanced food and favors, by
default, a more balanced diet."
While most of the 20 amino acids can be synthesized by the body, eight
must be obtained from food.
Omnivorous animals such as humans are known to consume less of a meal
lacking essential amino acids than meals that are nutritionally
To determine the role of GCN2 kinase in such behavior, Ron and
colleagues inactivated the enzyme in the brains of mice.
The mice subsequently had no aversion to imbalanced meals.
"There's no reason to believe that the same mechanism isn't at work in
humans," says Ron.
But cultural influences and an instinctive drive to consume
calorie-dense foods, says Ron, might override the molecular
nutritionist's ability to promote a balanced diet.
The research is reported in the journal Cell Metabolism (read
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