The body WILL produce what it needs to when given the chance via a healthy ,
natural diet...which is pretty non existant in most these days.
Yogurt is a great source of bacteria...especially 'local'/indiginious to your area.
(When travelling abroad it's always good to eat the local yogurt to aclimate the bod to local food). There is some good Soy yogurt ,too.
Natto, or fermented soybeans, is an excellent source(protein,too) as well as the Chinese fruit, Lo Han Kuo . Google both for info...