Exploring the Possible Relationship Between Mother’s Dietary Intake of Tryptophan and Melatonin Levels in Her Breast Milk

<b><i>Background and Objective:</i></b> Tryptophan is an essential amino acid that is not produced in the body and can only be consumed through diet. Tryptophan is a precursor for serotonin, which, in turn, helps produce melatonin. Melatonin exhibits a circadian rhythm, peaking at night and dissipating during the day, with basal levels significantly differing between mothers. Both tryptophan and melatonin are found in breast milk. The aim of this project is to determine if the variations in tryptophan levels found in breast milk are related to the amount of melatonin detected in breast milk and the amount of tryptophan consumed in a mother's diet. <b><i>Method:</i></b> Three hundred and eighty breast milk samples were collected by participants at four timepoints across 5 consecutive days, along with a food diary. Melatonin and tryptophan in these samples were measured. <b><i>Results:</i></b> No significant relationship was found between tryptophan and melatonin in breast milk or diet. There were also no significant changes in tryptophan across the day or night, suggesting no circadian rhythm timing like melatonin. <b><i>Discussion:</i></b> The findings from this study differ from earlier research, suggesting that more work needs to be completed in this area to understand the variation of melatonin in breast milk across mothers.