It has been proven that kefir improves mood because it contains a high amount of tryptophan and helps the production of serotonin in the brain. Kefir is used to combat the effects of anxiety and depression.
Kefir also helps us combat insomnia, it is recommended to drink a glass of natural kefir one hour before going to sleep.
References:
1. https://www.ncbi.nlm.nih.gov/pubmed/25590029
