Kefir is used for probiotic benefit. For vegans or people with intolerance for dairy, the best substitute for Plain kefir is Greek Yogurt.
If you are vegan or have a dairy intolerance the good news is that both Kefir and Greek yogurt are available in rice and coconut based forms.
Hope this helps. If you have further concerns, please email us at email@example.com. We are happy to assist you.