What Is Corn Oil?

Corn oil is an edible oil made from the seeds of corn, also called kernels. It has a bland flavor and light color.

Composition

According to the Corn Refiners Association’s website, corn oil contains around 60 percent polyunsaturated, 25 to 30 percent monounsaturated and 10 to 15 percent saturated fats. It is high in omega-6 fatty acids. Corn oil is a rich source of the essential fatty acid linoleic acid, which is needed for growth as well as optimal quality of skin and hair. Corn oil is a good source of tocopherols, including vitamin E. Tocopherols serve as antioxidants in the body and help prevent rancidity.

Extraction of Corn Oil

As mentioned in Encyclopaedia Britannica Online, oil makes up around half of the germ in the corn kernel. After the milling process, which separates the germ from the remainder of the kernel, the corn germ is dried in a kiln. The oil is then extracted from the germ using pressure. A solvent such as hexane is used to extract the remaining oil from the compressed corn kernels, and after the solvent is evaporated, the remainder of the corn germ is used for hominy feed and given to animals.

Uses

Corn oil can be used in salad dressings, baking and for frying foods. It can also be commercially hydrogenated to saturate some of its double bonds to produce margarine. Corn oil can also be used to make biodiesel fuel to power motor vehicles, as per a 2006 article in "Biodiesel" magazine.

Food Label Health Claims

According to the U.S. FDA, corn oil and corn oil containing products are allowed to post a claim on their labels saying that they can reduce the risk of heart disease. As per the FDA’s website, vegetable oil blends, salad dressings, shortenings and other similar products that contain 4 grams or more corn oil per reference amount, are low in cholesterol and sodium, and do not contain more than 4 g of saturated fat per reference amount can carry this health claim. Also according to the FDA’s website, very limited and preliminary scientific evidence suggests that eating about 1 tablespoon of corn oil daily may reduce the risk of heart disease if it replaces a saturated fat due to the unsaturated fat content in corn oil.

Possible Side Effects

As with many things, it is best to use corn oil only in moderation. Although it is more favorable than saturated fat, it is a fat, so it has 9 calories per gram, which is twice as much as any proteins or carbohydrates. Excess fat intake of any type of fat can lead to weight gain. It is high in polyunsaturated fatty acids, and contains linoleic acid. A research study of 37 healthy volunteers that was published in the British Journal of Nutrition in 2010 found that corn oil led to impaired endothelial (artery wall) function. This study did not find that corn oil promoted inflammation, although omega-6 fatty acids tend to promote inflammation, whereas omega-3 fatty acids generally have an anti-inflammatory effect.