19 May 2020 --- Feeding kefir to mice has modulated their behavior via the gut-brain axis (GBA), according to a new APC Microbiome Ireland study. Its findings show that two varieties of kefir, Fr1 and UK4, had different and positive effects on the immune system and various behaviors of the mice. As kefir demand continues to rise in the gut health space, this research supports the recent broadening of the definition of psychobiotics to include fermented foods and could optimize future generations of kefir products.