MTHFR and the gallbladder are linked, but not directly. Bile production and gallbladder function are deeply connected to liver metabolism, nutrient status, phospholipid production, inflammation, cholesterol balance, and methylation. That means common MTHFR gene variants may influence gallbladder health indirectly, not because MTHFR “controls the gallbladder,” but because methylation helps support several biochemical pathways that make healthy bile possible.