Dietary fat
• Dietary fat is the most concentrated source of food energy equal to about 9 kilocalories per gram.
· Dietary fat also provides the essential fatty acid linoleic acid which is very important in normal metabolism.
· Other than the need for adequate quantities of linoleic acid, there is no specific requirement for dietary fat.
· Diets containing as little as 5-10% of total calories as fat appear to be safe and well tolerated.
• Dietary fats are composed primarily of fatty acids and dietary cholesterol.
· Fatty acids molecules contain either no carbon double bonds (saturated), one carbon double bond (monounsaturated), or more than one carbon double bond (polyunsaturated).
· Saturated fatty acids are associated with increased serum cholesterol.
· Polyunsaturated and monounsaturated fatty acids lower serum cholesterol.
· Trans-fatty acids are a particular form of unsaturated fat found in partially hydrogenated vegetable oils and is known to raise serum cholesterol levels.
· Saturated fats are solid at room temperature and in general are derived from animal foods.
· Unsaturated fats are liquid at room temperature and in general are derived from plant foods.
· The Polyunsaturated fatty acid linoleic acid is an essential nutrient and is required by the body for the synthesis of arachidonic acid, the major precursor of prostaglandins.
· Deficiency of linoleic acid results in dermatitis, hair loss, and impaired wound healing.
· Approximately 5 grams of linoleic acid per day is required to prevent essential fatty acid deficiency.
February 4, 2009
Posted on February 4, 2009
