Fats supply energy and essential fatty acids and serve asa carrier for the absorption of the fat-soluble vitamins A, D, E, and K and carotenoids. Fats serve as building blocks of membranes and play a key regulatory role in numerousbiological functions. Dietary fat is found in foods derivedfrom both plants and animals. The recommended total fatintake is between 20 and 35 percent of calories for adults. A fat intake of 30 to 35 percent of calories is recommendedfor children 2 to 3 years of age and 25 to 35 percent ofcalories for children and adolescents 4 to 18 years of age. Few Americans consume less than 20 percent of caloriesfrom fat. Fat intakes that exceed 35 percent of calories areassociated with both total increased saturated fat andcalorie intakes.
To decrease their risk of elevated low-density lipoprotein (LDL) cholesterol in the blood, most Americans need to decrease their intakes of saturated fat and trans fats, and many need to decrease their dietary intake of cholesterol. Because men tend to have higher intakes of dietary cholesterol, it is especially important for them to meet this recommendation. Population-based studies of American diets show that intake of saturated fat is more excessive than intake of trans fats and cholesterol. Therefore, it is most important for Americans to decrease their intake of saturated fat. However, intake of all three should be decreased to meet recommendations. Diets can be planned to meet nutrient recommendations for linoleic acid and α-linolenic acid while providing very low amounts of saturated fatty acids.
Based on 1994–1996 data, the estimated average daily intake of trans fats in the United States was about 2.6 percent of total energy intake. Processed foods and oils provide approximately 80 percent of trans fats in the diet, compared to 20 percent that occur naturally in food from animal sources. Trans fat content of certain processed foods has changed and is likely to continue to change as the industry reformulates products. Because the trans fatty acids produced in the partial hydrogenation of vegetable oils account for more than 80 percent of total intake, the food industry has an important role in decreasing trans fatty acid content of the food supply. Limited consumption of foods made with processed sources of trans fats provides the most effective means of reducing intake of trans fats. By looking at the food label, consumers can select products that are lowest in saturated fat, trans fats, and cholesterol.
To meet the total fat recommendation of 20 to 35 percent of calories, most dietary fats should come from sources of polyunsaturated and monounsaturated fatty acids. Sources of omega-6 polyunsaturated fatty acids are liquid vegetable oils, including soybean oil, corn oil, and safflower oil. Plant sources of omega-3 polyunsaturated fatty acids (α-linolenic acid) include soybean oil, canola oil, walnuts, and flaxseed. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are omega-3 fatty acids that are contained in fish and shellfish. Fish that naturally contain more oil (e.g., salmon, trout, herring) are higher in EPA and DHA than are lean fish (e.g., cod, haddock, catfish). Limited evidence suggests an association between consumption of fatty acids in fish and reduced risks of mortality from cardiovascular disease for the general population. Other sources of EPA and DHA may provide similar benefits; however, more research is needed. Plant sources that are rich in monounsaturated fatty acids include vegetable oils (e.g., canola, olive, high oleic safflower, and sunflower oils) that are liquid at room temperature and nuts.
Considerations for Specific Population Groups
Evidence suggests that consuming approximately two servings of fish per week (approximately 8 ounces total) may reduce the risk of mortality from coronary heart disease and that consuming EPA and DHA may reduce the risk of mortality from cardiovascular disease in people who have already experienced a cardiac event.Federal and State advisories provide current information about lowering exposure to environmental contaminants in fish. For example, methylmercury is a heavy metal toxin found in varying levels in nearly all fish and shellfish. For most people, the risk from mercury by eating fish and shellfish is not a health concern. However, some fish contain higher levels of mercury that may harm an unborn baby or young child's developing nervous system. The risks from mercury in fish and shellfish depend on the amount of fish eaten and the levels of mercury in the fish. Therefore, the Food and Drug Administration (FDA) and the Environmental Protection Agency are advising women of childbearing age who may become pregnant, pregnant women, nursing mothers, and young children to avoid some types of fish and shellfish and eat fish and shellfish that are lower in mercury. For more information, call FDA’s food information line toll-free at 1-888-SAFE-FOOD or visit http://www.cfsan.fda.gov/~dms/admehg3.html.
Lower intakes (less than 7 percent of calories from saturated fat and less than 200 mg/day of cholesterol) are recommended as part of a therapeutic diet for adults with elevated LDL blood cholesterol (i.e., above their LDL blood cholesterol goal). People with an elevated LDL blood cholesterol level should be under the care of a healthcare provider.
Source:
The Dietary Guidelines for Americans
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