Lipids and Fats

• Excessive consumption of sugar can lead to obesity and possibly heart disease or cancer.
• Fats belong to a group of organic compounds called lipids.
• The word lipid is derived from lipos, a Greek word for fat.
• Forms of the word lipid are found in several fat-related health terms such as blood lipids, hyperlipidemia, and lipoproteins.
• Fats are greasy substances that are not soluble in water.
• Fats are digested by 95% but the process is complex.
• A plaque is a fatty deposit on the interior of artery walls.
• Fats are not digested in the mouth or stomach, they are digested only slightly in the stomach where gastric lipase acts on emulsified fats such as those found in cream and egg yolk.
• The chemical digestion of fats occurs mainly in the small intestine.
• Heart attack and stroke are reduced by consuming fats.
• Fats must be mixed well with the gastric juices before entering the small intestine.
• Fats are soluble in some solvents such as ether, benzene, and chloroform.
• Fats provide a more concentrated source of energy than carbohydrates; each gram of fat contains 9 calories.
• Fat-rich foods are generally more expensive than carbohydrate-rich foods.
• Like carbohydrates, fats are composed of carbon, hydrogen, and oxygen but with a substantially lower proportion of oxygen.
• Fats are essential for the functioning and structure of body tissues.
• Fats are a necessary part of cell membranes (cell walls).
• Fats contain essential fatty acids and act as carriers for fat-soluble vitamins A, D, E, and K.
• The fat stored in body tissues provides energy when one cannot eat, as may occur during some illness and after abdominal surgery.
• Adipose (fatty) tissue protects organs and bones from injury by serving as protective padding and support.
• Body fat also serves as insulation from cold.
• Fats provide a feeling of satiety (satisfaction) after meals due to their flavor and slow rate of digestion, which delays hunger.
• Fats are present in both animal and plant foods.
• The animal foods that provide the richest sources of fats are meats, especially fatty meats such as bacon, sausage, and luncheon meats; whole, low-fat, and reduced-fat milk; cream; butter; cheeses made with cream; egg yolks; and fatty fish such as tuna and salmon.
• Omega-6 (linoleic acid) has a cholesterol-lowering effect.
• Monounsaturated fats have no effect on high-density lipoproteins (HDLs) (“good cholesterol”).
• Polyunsaturated fats contain two or more places among the carbon atoms of its fatty acids where there are fewer hydrogen atoms attached than in saturated fats.
• Examples of foods containing monounsaturated fats are olive oil, peanut oil, canola oil, avocados, and cashew nuts.
• Omega-3 fatty acids have been reported to help lower the risk of heart disease.
• The two major fatty acids denoted by the placement of their double bonds are the omega-3 and omega-6 fatty acids.
• The point at which carbon-carbon double bonds occur in a polyunsaturated fatty acid is the determining factor in how the body metabolizes it.
• It is recommended that one consume 15% of total daily calories as monounsaturated fats.
• Foods containing high proportions of polyunsaturated fats are usually soft or oily.
• Monounsaturated fatty acid (oleic acid: ω-9) has one place among the carbon atoms of its fatty acids where there are fewer hydrogen atoms attached than in saturated fats.
• Saturated fatty acid (stearic acid) consists of a methyl group and an acid group.
• Examples of foods containing polyunsaturated fats include cooking oils made from sunflower, safflower, or sesame seeds or from corn or soybeans; soft margarines whose major ingredient is liquid vegetable oil; and fish.
• Research indicates that monounsaturated fats lower the amount of low-density lipoprotein (LDL) (“bad cholesterol”) in the blood, but only when they replace saturated fats in one’s diet.
• Polyunsaturated fats should not exceed 8% of total daily calories.
• The use of supplements of either of these fatty acids is not recommended.
• The plant foods containing the richest sources of fats are cooking oils made from olives, sunflower, safflower, or sesame seeds or from corn, peanuts, soybeans, margarine, nuts, avocados, coconut, and cocoa butter.