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5-HTP decreases food intake in stressed rats and those deprived of food
Monday, September 27, 2010 6:25 am Email this article
5-Hydroxy-L-tyrptophan (5-HTP) dose-dependently decreased food intake in rats deprived of food, and in rats that were stressed according to a study by Richard Wurtman of the Massachusetts Institute of Technology and Tim Maher from the Massachusetts College of Pharmacy and Health Sciences in Boston, Mass. Dose-dependent effect
The reduction of food intake was dose-dependent, that is, the higher the dose the greater the effect.
5-HTP eight times more effective at reducing stress-induced eating
However, the effect was at least 8 times more effective for the rats that were stressed than those that had been deprived of food.
The amino acid L-valine blocked the effect
The effect was blocked by giving rats the amino acid L-valine—another large neutral amino acid which competes with 5-HTP for taxi molecules to carry them into the brain.
This suggests that 5-HTP should be taken away from protein. (Amino acids such as L-valine are the building blocks of protein.)
No carbidopa necessary
This appetite suppression occurred without giving the animals a drug called carbidopa which prevents 5-HTP from being converted to serotonin in the body before reaching the brain.
Some researchers previously believed that it was necessary to give 5-HTP with carbidopa to be effect, however, this does not seem to be the case.
Conclusion: 5-HTP may reduce stress-induced eating
“These observations suggest that 5-HTP may be useful in controlling the excessive food intake sometimes generated by stress, even if given without decarboxylase inhibitors [carbidopa] or other drugs,” the researchers concluded.
5-HTP is the immediate precursor to serotonin
5-HTP is the immediate precursor to serotonin.
5-HTP increases leptin, carbidopa reduces this effect
A previous study found that 5-HTP increases leptin—the hormone released by fat cells that decreases appetite and may increase metabolism.
However, they also found that giving carbidopa with 5-HTP suppressed this effect, suggesting that it is better to give 5-HTP alone than with carbidopa.
Practical advice: 5-HTP should be taken on an empty stomach
5-HTP should be taken on an empty stomach away from protein. This study shows that taking it with protein will block the effect.
Other articles about 5-HTP
Other articles about 5-HTP can be found here.
Amer A, Breu J, Mcdermott J, Wurtman R, Maher T. 5-hydroxy-l-tryptophan suppresses food intake in food-deprived and stressed rats. Pharmacol Biochem Behav. 2004 Jan, 77(1):137-43.
AUTHOR’S CONTACT INFORMATION
Department of Pharmaceutical Sciences
Massachusetts College of Pharmacy and Health Sciences
Boston, MA, US
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