When you hear the word tryptophan, you probably think of turkey and sleepiness. What you may not know is that tryptophan is one of the 10 essential amino acids our bodies need in order to synthesize protein. It helps produces messengers that communicate with our nervous system, and yes, it's also related to relaxation, restfulness, and sleep. Turkey isn't the only source of tryptophan, though, so take this quiz to learn about this amino acid and what other foods contain it.

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