Do the plants you eat make calming and mood-improving peptides? These are a small or a modest string of amino acids–like a collection of pearls.
Yes.
- Small- and medium-sized peptides released from plants such as soybean, leaf, and grain regulate emotion.
- Some middle-sized peptides exhibit antidepressant-like and anxiolytic-like effects through the vagus nerve.
- Food-derived small peptides in the bloodstream may act directly in the brain.
Proteins are degraded by proteases with different substrate specificities in the intestinal tract, producing peptides with varying amino acid chain lengths and sequences. Adding the word end -ase indicates that it is an enzyme.
In fermented and processed foods, oligopeptides digest proteins from raw microorganisms, such as thermolysin and subtilisin, before ingestion. Consequently, enzymatic hydrolysis in the gastrointestinal tract and by microorganisms identifies bioactive peptides derived from food proteins.
More is in this huge article. The abstract has little new information and is not here.
FMI: Peptide. 2021 Aug:142:170569. doi: 10.1016/j.peptides.2021.170569. Epub 2021 May 10. Neuromodulatory peptides: Orally active anxiolytic-like and antidepressant-like peptides derived from dietary plant proteins. Takafumi Mizushige 1 PMID: 33984426 DOI: 10.1016/j.peptides.2021.170569