Thanks Deb,
I realize I forgot two points:
26. There is one fat that should be avoided: trans fat (partially hydrogenated oil). Replacement of just 2% of energy from trans unsaturated fats with unsaturated fats would result in a 53% risk reduction for coronary heart disease. The U.S. government Board of Food and Nutrition recently issued a report on trans fat saying "that dietary trans fatty acids are more deleterious with respect to coronary heart disease than saturated fatty acids."(51) This report suggests "a Tolerable Upper Intake Level (UL) of zero."(52)
27. Although the government's Dietary Guidelines for Americans recommends that Americans cut their daily saturated fat intake to 10% and certain researchers recommend replacing saturated fat with polyunsaturated fat, there appear to be valid reasons to fear replacing saturated fats with polyunsaturated fats.(53) When the arterial plaque of deceased humans was examined it contained polyunsaturated fats.(54) Oxidation of fats whether it occurs in the body or whether oxidized fat is ingested is known to lead to clogging of the arteries. The fat that oxidizes the easiest is polyunsaturated fat.(55) Saturated fats are the most stable.(56)
References:
51 Ascherio A, Hennekens CH, Buring JE, Master C, Stampfer MJ, Willett WC. 1994. Trans-fatty acids intake and risk of myocardial infarction. Circulation 89:94-101.
52 Letter Report on Dietary Reference Intakes for Trans Fatty Acids; Institute of Medicine in the National Academy of Sciences, July 10, 2002.
http://www.iom.edu/iom/iomhome.nsf/Pages/FNB+Reports.
53 Dietary Guidelines for Americans
http://www.nal.usda.gov/fnic/dga/dga95/lowfat.html
54 Felton CV et al: Dietary polyunsaturated fatty acids and composition of human aortic plaques. Lancet 1994; 344:1195-1196.
55 Nippon Rinsho, Modified low-density lipoprotein. 1994 Dec; 52(12):3090-5.
56 Bourre JM, Piciotti M. Alterations in eighteen-carbon saturated, monounsaturated and polyunsaturated fatty acid peroxisomal oxidation in mouse brain during development and aging. Biochem Mol Biol Int 1997 Mar;41(3):461-8.