The Rise of Vegetable Margarine

Modern margarine is now made not from solid animal fats, but from normally liquid vegetable oils. This shift was made possible around 1900 by German and French chemists who developed the process of hydrogenation, which hardens liquid oils by altering the structures of their fatty acids. Hydrogenation allowed manufacturers to make a butter substitute that spreads easily even at refrigerator temperature, where butter is unusably hard. An unanticipated bonus for the shift to vegetable oils was the medical discovery after World War II that the saturated fats typical of meats and dairy products raise blood cholesterol levels and the risk of heart disease. The ratio of saturated to unsaturated fat in hard stick margarine is only 1 to 3, where in butter it is 2 to 1. Recently, however, scientists have found that trans fatty acids produced by hydrogenation actually raise blood cholesterol levels. There are other methods for hardening vegetable oils that don’t produce trans fatty acids, and manufacturers are already producing “trans free” margarines and shortenings.