While both kefir and yogurt are cultured milk products, they contain different types of beneficial bacteria. Yogurt contains transient beneficial bacteria that keep the digestive system clean and provide food for the friendly bacteria that already are present. Kefir actually colonizes the intestinal tract -- a feat that yogurt cannot match.
Additionally, Kefir contains several major strains of friendly bacteria not commonly found in yogurt: Lactobacillus Caucasus, Leuconostoc, Acetobacter species, and Streptococcus species. It also contains beneficial yeasts, such as Saccharomyces kefir and Torula kefir, which dominate, control and eliminate destructive pathogenic yeasts in the body by penetrating the mucosal lining where unhealthy yeast and bacteria reside -- forming a virtual SWAT team that housecleans and strengthens the intestines. Consequently, the body becomes more efficient in resisting pathogens like E. coli and intestinal parasites.
Kefir's active yeast and bacteria provide more nutritive value than yogurt by helping digest the foods that you eat and by keeping the colon environment clean and healthy. The curd size of kefir is smaller than yogurt, so it's also easier to digest, making it an ideal food for babies, the elderly, and anyone with digestive disorders.
