An essential amino acid and precursor to serotonin and melatonin. Competes with other large neutral amino acids for transport into the brain, which limits the effect of protein-rich sources.
2 foods, grouped by presence band. Bands are used instead of amounts because compound content swings widely with cultivar, soil, storage and preparation — a single number per food would look more precise than the measurements justify.
Consistently reported in this food in amounts researchers treat as meaningful.
Recorded in this food without a dependable quantity attached to it.