Elizabeth S. Reames | 5/27/2005 1:17:32 AM
In an attempt to lose weight, some people try to eliminate all fats and oils from their diets. That’s a mistake, according to LSU AgCenter nutritionist Dr. Beth Reames.
"Fats and oils are needed for a healthful diet," Reames says, explaining, "They supply energy and essential fatty acids and serve as building blocks of cell membranes."
She adds they also serve as carriers for the absorption of the fat-soluble vitamins A, D, E and K and carotenoids, such as beta-carotene.
The 2005 Dietary Guidelines for Americans recommends a daily total fat intake between 20 percent and 35 percent of calories for people over age 18, with most fats coming from sources of polyunsaturated and monounsaturated fatty acids, such as fish, nuts and vegetable oils.
The range of recommended fat intake for a person needing 2,000 calories a day is from 44 grams (20 percent of calories) to 78 grams (35 percent of calories). For children 2 to 3 years of age, the recommendation is between 30 percent and 35 percent of calories. For children and adolescents from ages 4 to 18, the range of recommended fat intake is 25 percent to 35 percent.
The Guidelines also recommend consuming less than 10 percent of calories from saturated fatty acids and less than 300 mg/day of cholesterol, and keeping trans fatty acid consumption as low as possible.
Reames explains the various kinds of fats and oils.
Monounsaturated fatty acids. MUFAs may help reduce blood cholesterol levels. Plant sources rich in MUFAs include nuts and vegetable oils, such as canola oil, olive oil, high oleic safflower and sunflower oils that are liquid at room temperature.
Polyunsaturated fats. PUFAs help lower blood cholesterol levels and reduce cholesterol deposits in artery walls. They may be of two types: 1) Omega-6, which includes liquid vegetable oils, such as soybean oil, corn oil and safflower oil; 2) Omega-3, which includes soybean oil, canola oil, walnuts and flaxseed. Fish and shellfish contain the beneficial long chain n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Saturated fatty acids. Eating too much saturated fat may increase blood cholesterol levels and increase risk of heart disease. Sources include animal products such as meat and dairy products. In general, animal fats are solid at room temperature.
Trans fatty acids. Trans fats are unsaturated fatty acids created when vegetable oil is chemically modified by the addition of extra hydrogen molecules ("hydrogenation") to increase a product’s shelf life and to make fats at room temperature hard instead of liquid. Trans fats may raise bad LDL cholesterol levels and lower good HDL cholesterol levels. Sources of trans fatty acids include hydrogenated/partially hydrogenated vegetable oils that are used to make shortening and commercially prepared baked goods, snack foods, fried foods and margarine. Trans fatty acids also are present in foods that come from ruminant animals, such as cattle and sheep. Foods include dairy products, beef and lamb.
Solid fats. Fats that are solid at room temperature, such as butter, lard and shortening, are generally higher than oils in saturated and/or trans fatty acids. These fats may be visible or may be a constituent of foods such as milk, cheese, meats or baked products. Solid fats come from many animal foods and can be made from vegetable oils through hydrogenation. A few plant oils, such as coconut oil and palm kernel oil, are high in saturated fats and for nutritional purposes should be considered the same as solid fats.
Oils. Fats that are liquid at room temperature, such as the vegetable oils used in cooking, generally are high in monounsaturated or polyunsaturated fats and low in saturated fats. They come from many different plants and from fish. Some common oils are corn oil, soybean oil, canola oil, cottonseed oil, olive oil, safflower oil, sunflower oil, walnut oil and sesame oil. Some foods are naturally high in oils, like nuts, olives, some fish and avocados.
For information on related family and consumer topics, link to the FCS Web site from the LSU AgCenter homepage, at www.lsuagcenter.com. For local information and educational programs, contact an extension agent in your parish LSU AgCenter office.