Trans fatty acids are a byproduct of partially hydrogenated oils (PHOs) and are created in a process called hydrogenation. During hydrogenation hydrogen gas is boiled through oil, allowing the released hydrogen ions to saturate the oil, resulting in double bonds.

What is it? Hydrogenated Soybean Oil is soybean oil (from soy bean plant (Glycine max)), which is liquid at room temperature, that has been processed by adding hydrogen to make it more saturated. Hydrogenation increases the oil’s stability and raises its melting point so that it is a solid at room temperature.

Some of the partially hydrogenated soybean oil has been converted to trans fatty acids. Trans fatty acids have been shown to increase the risk of atherosclerosis and coronary heart disease due to their in vivo effects in two ways.

Partially hydrogenated oils are most commonly found in foods that also have saturated fat, such as:

• margarine.
• vegetable shortening.
• packaged snacks.
• baked foods, especially premade versions.
• ready-to-use dough.
• fried foods.
• coffee creamers, both dairy and nondairy.

To convert soybean, cottonseed, or other liquid oil into a solid shortening, the oil is heated in the presence of hydrogen and a catalyst. That hydrogenation process converts some polyunsaturated fatty acids to monounsaturated and saturated fatty acids.

Since the process of hydrogenation adds hydrogen atoms to oil, it will reduce the number of unsaturated fatty acids and increase the number of saturated fatty acids in the oil. Sometimes partial hydrogenation is carried out on oil as this will result in a lower level of saturated fatty acids formed in the product.

Hydrogenated soy oil, also known as soybean oil, is a major food fat in the American dietary. Food uses of hydrogenated soybean oil are in the production of margarine, shortening, and salad and cooking oils. It is often used for frying and baking and is marketed as vegetable oil.

Hydrogenated oils are oils that have had hydrogen added to them to make them less likely to spoil. The difference between partially hydrogenated and fully hydrogenated fats is that the partial hydrogenation creates trans-fats, while fully hydrogenated, the oil returns to a “zero trans-fat” level.

Partially hydrogenated oil is often found in many food products, including margarine, premade baked goods (cookies, piecrusts and crackers) chips, fried foods, refrigerated dough, creamer and vegetable shortening. These types of products should be consumed as little as possible.