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February 2007 – Fat is Good, But ...
For good health, people need some fat in their diet. Fats provide energy and essential fatty acids that maintain cell function and the nervous system, absorb certain vitamins and perform other vital functions.
But too much fat may increase a person’s risk of weight gain, heart disease and certain types of cancer.
“All fats are not the same. The type of fat is more important than the amount of fat a person eats,” said Tracey Brand, a Froedtert Hospital registered dietitian and coordinator of corporate wellness. “For optimal health, it’s important to know the difference between ‘good’ fats and ‘bad’ fats.”
Trans fatty acids (trans fat) and saturated fat are considered “bad” fats. “Trans fat and saturated fat raise the LDL cholesterol levels in the blood, which blocks the arteries and increases the risk of heart disease,” Brand said.
Saturated FatSaturated fats are almost solid at room temperature. Most animal fats, such as those in lard, meat fat, dairy products (milk, butter, ice cream and cheese) are saturated. Saturated fat is also found in some vegetable oils (palm, palm kernel and coconut oils). Many foods that contain trans fats also contain saturated fat.
Saturated raises the “bad” LDL cholesterol in your blood.
Unsaturated fats, which come in two forms, are better for people than saturated fats. Unsaturated fats are:
- Monounsaturated fat — fat that remains liquid at room temperature, but are less fluid when cold. Sources include olive, peanut and canola oils, avocadoes, olives and many nuts and seeds.
- Polyunsaturated fat — fat that is liquid at room temperature and when cold. Sources include corn, safflower, sunflower, safflower and soybean oils, fish, and various nuts and seeds.
Monounsaturated fat is best, because it lowers the bad cholesterol and raises the good cholesterol in your blood. Polyunsaturated fat also lowers the bad cholesterol.
Trans Fat Food manufacturers created trans fat chemically once research clearly revealed that saturated fat damages arteries. They make trans fat by adding hydrogen to liquid oil. This process, called hydrogenation, turns the oil into a solid fat, which increases the shelf life and flavor stability of foods. Trans fat is found in vegetable shortenings, some margarines, crackers, cookies, snack foods and other foods made with or fried in partially hydrogenated oils. (Trans fat also occurs naturally, in small amounts, in meat and dairy products.)
Oil is called hydrogenated when the process forms a solid fat, and partially hydrogenated when the process forms a semi-solid fat (with a consistency like butter).
Unlike other types of fat, trans fats are not needed by the body. Trans fat raises blood cholesterol levels more than other forms of fat. It increases the “bad” LDL cholesterol, while lowering levels of “good” HDL cholesterol in the body. This combination increases the risk of heart disease. Trans fat also is associated with cancer, diabetes, immunity disorders, obesity and other health problems.
Read the Label The U.S. Food and Drug Administration’s dietary guidelines suggest that 30 percent or less of daily calories come from fat, and less than 10 percent of calories come from saturated fat. Since 1993, the FDA has required food manufacturers to list the percentage of fat in their products on Nutrition Facts labels. The label also includes the suggested daily value for total fat, saturated fat and cholesterol. In 2006, the FDA added trans fat content to the label (there is no recommended daily value for trans fat).
“When comparing foods, read the Nutrition Facts label, and choose foods with least amounts of saturated fat and trans fat,” Brand said. “Replace saturated and trans fats in your diet with mono- and polyunsaturated fats.”
Foods that work to lower cholesterol include:
- Omega 3 fatty acids, found in salmon, trout, tuna, canola oil, flaxseed, soybeans and walnuts
- Flax; add 2 tablespoons per day to yogurt or orange juice
- Soy from soy milk, soy nuts, soy cheese and tofu
Nutrition ResourcesSmall Stones, a health resource center of Froedtert & the Medical College of Wisconsin, offers many resources related to nutrition:
- The Harvard Medical School Guide to Lowering Your Cholesterol by Mason W. Freeman, MD
- The Road to a Healthy Heart Runs Through the Kitchen by Joseph C. Piscatella
- Dr. Dean Ornish’s Program for Reversing Heart Disease by Dean Ornish, MD
- Eating for Lower Cholesterol by Catherine Jones with Elaine B. Trujillo, MS, RD, CNSD
- American Dietetic Association Complete Food and Nutrition Guide by Roberta Larson Duyuff MS, RD, FADA, CFCS
Author: Marla Fraunfelder Date: Feb. 1, 2007 | Medical Reviewer: | Tracey Brand | | Registered Dietitian |
Online Editor(s): Christopher Sadler
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