Tryptophan concentrations and ratios below normal in obese subjects.
As a background, tryptophan crosses the blood-brain barrier and gets converted to serotonin. Serotonin is a neurotransmitter used for many purposes included onset of sleep and satiety. In order for tryptophan to cross the BBB effectively, there cannot be much competition from other amino acids.
In this study, the researchers found that plasma tryptophan concentrations are low. The significance of this finding is uncertain at this point, but the addition of 5-HTP supplementation may be a good route to take for obesity.
AJCN — Abstracts: Breum et al. 77 (5): 1112