Kefir is a fermented milk drink that originated in the Caucasus region of Eurasia and is prepared by inoculating cow, goat, or sheep’s milk with kefir grains, a combination of bacteria and yeasts in a matrix of proteins, lipids, and sugars. Traditional kefir was made in skin bags that were hung near a doorway and knocked by everyone passing through to help keep the milk and kefir grains mixed. Today, kefir is popular due to research into its health benefits. What are these benefits? Discuss