Kefir peptides improved nonalcoholic fatty liver diseases via activation of Janus kinase 2 (JAK2) signal transduction through the JAK2/signal transducer and activator of transcription protein 3 (STAT3) and JAK2/AMP-activated protein kinase (AMPK) pathways in a high fructose-induced fatty liver animal model44. The gene discussed is STAT3; the disease is metabolic dysfunction-associated steatotic liver disease.