-IBIS-1.5.0-
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constituents
fats and lipids
nutrition
definition
fats and lipids
» lipids are divided into three major classes: triglycerides, phospholipids (lecithin), and cholesterol
» lipids are vital component of nutrition and perform necessary functions: basic component of cell membrane, cell metabolism, enzyme reactions, synthesis and utilization of sterol hormones and hormone-like prostaglandins, carrier for fat soluble vitamins A, D, E and K, memory and nervous system function
» all fats and oils are a combination of saturated and unsaturated fatty acids; fats are classified by the fatty acid structure of the major constituent oil
» pesticides, which are very fat soluble, tend to be concentrated in oil products; therefore it is a good idea to buy organic oils whenever possible. Oils especially high in pesticide residue: soy, corn, cottonseed, canola
» store oils in refrigerator, tightly capped away from light
» buy oils in small quantities and use before they become rancid
saturated fats:
» solid at room temperature (butter, lard)
» derived from animal products
» fatty acid chain contains no double bonds (that is: all the bonds are "saturated" by hydrogen atoms)
polyunsaturated fats:
» liquid at room temperature
» derived from plant sources
» fatty acid chain contain two or more double bonds; therefore are more easily oxidized by light, heat and air (that is: the double bond is attacked by oxygen) to become rancid
» lowers total serum cholesterol by lowering both HDL and LDL
» they are implicated in some types of cancer, especially breast
» high in essential fatty acids
mono-unsaturated fats:
» liquid at room temperature
» derived from plant sources
» fatty acid chain contains only one double bond; therefore are more resistant to oxidation
» lowers total serum cholesterol by lowering LDL and leaving HDL levels unchanged
footnotes