Soya oil is the oil extracted from soya beans, one of the world’s most produced vegetable oils, used for cooking, salad dressings, and margarine manufacture. Neutral in flavour and high in polyunsaturated fats, it suits frying and general cooking, and hydrogenated versions once dominated margarine and shortening before trans-fat concerns ended that era. It is rich in omega-6 fatty acids and contains vitamin E and plant sterols. Folk claims credit it with protective effects against breast cancer, though the evidence is preliminary and contested. Like all commodity oils it is refined, bleached, and deodorised for a bland, stable product. Its ubiquity in processed food makes it one of the defining fats of the modern diet.