The Effects of Dietary Tryptophan on Affective Disorders

Using a randomized crossover study design, 25 healthy young adults were examined for differences in anxiety, depression, and mood after consuming a high tryptophan and a low tryptophan diet for 4 days each. There was a 2 week washout between the diets. A within-subjects analysis of the participants' mood indicated significantly (p < .01) more positive affect scores after consuming a high tryptophan diet as compared to a low tryptophan diet. Negative affect differences between the diets were not statistically significant (p > .05). Also, consuming more dietary tryptophan resulted in (p < .05) less depressive symptoms and decreased anxiety.