Time for an Oil Change?
With so many cooking and salad oils on store shelves these days, which should you choose?
A stroll down the cooking oil aisle of your local supermarket may leave you
shaking your head. So many choices… olive, corn, canola, safflower. The list
seems to go on and on. Which do you choose?
Before answering that question, it helps to know a bit about cooking oils in
the first place.
Fats and oils are made up of "building blocks" called fatty acids.
Each type of fat or oil is a mixture of different fatty acids:
- Saturated fatty acids are found primarily in animal sources such as
meat and poultry, whole or reduced-fat milk, and butter. Some vegetable oils
like coconut, palm kernel oil, and palm oil have saturated fats. Saturated fats
are usually solid at room temperature.
- Monounsaturated fatty acids are usually found in vegetable oils such
as canola, olive, and peanut oils. They are liquid at room temperature.
- Polyunsaturated fatty acids are found mainly in vegetable oils such
as safflower, sunflower, corn, flaxseed, and canola oils. Polyunsaturated fats
are also the main fats in seafood. They are liquid or soft solids at room
temperature. Specific polyunsaturated fatty acids, such as linoleic acid and
alpha-linolenic acid, are called essential fatty acids. They are necessary for
cell structure and making hormones. The body does not manufacture its own
essential fatty acids; they must be obtained from the foods we eat.
- Trans fatty acids are formed when vegetable oils are processed into
margarine or shortening. Sources of trans fats in the diet include snack foods
and baked goods made with partially hydrogenated vegetable oil or vegetable
shortening. Trans fatty acids also occur naturally in some animal products such
as dairy products.
Eating too many foods high in saturated fat may increase blood levels of LDL
(bad) and total cholesterol. High blood levels of LDL and total cholesterol are
risk factors for heart disease.
Trans fatty acids act like saturated fats and raise LDL cholesterol levels;
they may also lower HDL (good) cholesterol in the blood. High levels of HDL are
protective against heart disease.
Eating foods high in monounsaturated fatty acids, on the other hand, may
help lower LDL cholesterol levels and decrease risk of heart disease. Eating
polyunsaturated fats in place of saturated fats decreases LDL cholesterol
While we should do what we can do stay away from saturated fats and trans
fatty acids, taking in a combination of monounsaturated and polyunsaturated
fats keeps us nutritionally balanced, says K.C. Hayes, professor of biology at
Fats and oils actually play an important role in how our body works, adds
Cindy Moore, MS, RD, director of nutrition therapy for the Cleveland Clinic and
spokeswoman for the American Dietetic Association. "Fats and oils provide a
concentrated source of energy for the body. Fats are used to store energy in
the body, insulate body tissues, and transport fat-soluble vitamins -- A, E, D,
and K -- through the blood. They also enhance the taste, aroma, and texture of
food, and contribute to a feeling of satiety, or fullness."