Which of the following amino acids is a precursor for serotonin?

Tryptophan is the correct choice as a precursor for serotonin. This amino acid plays a crucial role in the synthesis of serotonin, a neurotransmitter that regulates mood, appetite, and sleep, among other functions. The body converts tryptophan into 5-hydroxytryptophan (5-HTP), which is then transformed into serotonin through a series of enzymatic reactions.

Understanding the role of tryptophan as a precursor helps emphasize the importance of dietary sources rich in this amino acid, such as turkey, nuts, and seeds, especially for those who may be managing mood disorders or other conditions influenced by serotonin levels. The biochemical pathway starting from tryptophan ties into a larger context of nutritional psychiatry, where the focus is on how nutrition impacts mental health.