An NIH study says that a supplement containing tyrosine, tryptophan, and blueberry extract showed promise in combating postpartum depression and sadness.
Affecting about 13% of moms between 1-4 weeks after birth, it can take a hard toll on the whole family. Adding a supplement containing those three nutrients help to counter increases in monoamine oxidase A, which has been shown to increase symptoms of depression and sadness.

Here is the link to the study:
https://www.ncbi.nlm.nih.gov/pubmed/?term=Selective+dietary+supplementation+in+early+postpartum+is+associated+with+high+resilience+against+depressed+mood