Vegetable oils long have been used as a basic cooking ingredient throughout the world. Today, a vast array of different types of vegetable oils can be found on supermarket shelves. Are these vegetable oils basically all the same or are certain types more healthful than others? Should a particular vegetable oil be used when preparing a specific food? To help answer these questions, here’s a look at what some of the different oils have to offer.
Just the facts: All vegetable oils are 100 percent pure fat. They consist of three types of fatty acids – monounsaturated, polyunsaturated and saturated. Monounsaturated fatty acids are missing one pair of hydrogen atoms on their chemical chain, while polyunsaturated fatty acids are missing two or more hydrogen pairs. Saturated fatty acids, on the other hand, have all of the hydrogen they can hold on their chemical chain.
Vegetable oils are classified by the predominant type of fatty acids they contain. For example, canola oil is considered a monounsaturated oil because 61 percent of its fatty acids are monounsaturated. In contrast, safflower oil is labeled a polyunsaturated oil because 71 percent of its fatty acids are polyunsaturated.
Potential health benefits associated with vegetable oils: Over the past several years, olive oil has received the most media attention in part due to its potential health benefits. Both olive oil and canola oil consist predominately of the monounsaturated fats that appear to be useful in helping lower total blood cholesterol. They also may help reduce certain risk factors for heart disease; help reduce the oxidation of LDL ("bad") cholesterol, which contributes to the hardening of the arteries; and may help some people with diabetes control their blood sugar. Canola oil, along with certain polyunsaturated oils such as walnut, soybean and flaxseed oil, provide an omega-3-fatty acid similar to the heart-healthy omega-3 fatty acids found in fish and thus may help reduce the risk of heart attacks. Polyunsaturated oils, in general, have been found to help lower total blood cholesterol.
Tropical oils (coconut, palm kernel and palm oil) received a bad reputation during the late 1980s and many health-conscious people stopped eating them, mostly because their high saturated fat content was associated with negative health consequences. However, researchers are now investigating whether palm oil may actually act like an unsaturated fat in the body and help reduce blood cholesterol levels. Studies also indicate that coconut oil has a neutral effect in most people and may even help protect against liver damage.
Cooking with vegetable oils: When using vegetable oils in the kitchen, keep in mind:
– Olive or canola oil tend to be better choices when cooking at high temperatures.
– When preparing Mediterranean dishes, olive oil is usually preferred.
– When cooking Asian dishes, peanut or dark sesame oil are good choices.
– Canola oil’s neutral taste makes it a good selection for everyday cooking.
Words to the wise: Vegetable oils contain 125 calories per tablespoon. To avoid unwanted weight gain, use vegetable oils to replace other high-calorie foods rather than using them in addition to other foods. Also, when vegetable oils are used in packaged foods they often undergo a chemical process called hydrogenation, which makes them act more like saturated fats, both in foods and in the body. Partially hydrogenated vegetable oils are more saturated and contain trans fats, which, when eaten regularly, may increase a person’s risk for heart disease.
by Pat Kendall, Ph.D., R.D., Food Science and Human Nutrition Specialist, Colorado State University, Cooperative Extension