Monounsaturated fatty atherosclerosis

There, also, is interest in dietary monounsaturated fatty acids because of their possible protective effect against oxidation of LDL cholesterol (101). There is appreciable evidence that the uptake of LDL cholesterol and the formation of fatty streaks in the intima of large blood vessels, which is considered an early lesion of atherosclerosis, is enhanced by the oxidation of the LDL cholesterol (102, 103). LDL cholesterol was found to be appreciably more stable to oxidation when subjects were fed diets rich in oleic acid than when fed linoleic acid enriched diets (104-106). 

The long-term influence of omega-3 fatty acid supplements is not known, and, for this reason, the American Heart Association has not recommended that supplements be taken (Krauss et al., 1996). There is a very real concern that dietary PUPAs of all types may enhance the accumulation of lipid oxidation products in lipoprotein particles, thus allowing the attack of lipid oxidation products on the pn>tein component of the LDL, the enhanced uptake of the damaged LDL by macrophages in the artery wall, and increased atherosclerosis (Allard ei ai, 1997 Felton ct si., 1994), (Monounsaturaled fatty acids are thought not to be involved in the oxidation scenario lead big to atherosclerosis.)... 

The principal nutritional focus in atherosclerosis has been dietary fat and cholesterol. It was concluded that (1) saturated fatty acids increase serum cholesterol and are its primary determinants (2) polyunsaturated fatty acids lower serum cholesterol and (3) monounsaturated fatty acids have no independent effect. Concerning cholesterol, it has been recommended to reduce dietary cholesterol intake to less that 300 mg/day. 

The preventive effects of a monounsaturated fatty acid (MUFA)-rich diet on atherosclerosis may be explained by the enhancement of HDL-C levels and impairement of LDL-C levels, LDL susceptibility to oxidation, cellular oxidative stress, thrombogenicity, and atheroma plaque formation (reviewed in ref. 94). 

Merkel M, Velez-Carrasco W, Hudgins LC, Breslow JL. Compared with saturated fatty acids, dietary monounsaturated fatty acids and carbohydrates increase atherosclerosis and VLDL cholesterol levels in LDL receptor-deficient, but... 

Medical evidence correlates a diet high in saturated fats with hardening of the arteries (atherosclerosis) and possible heart attack. Table 22.2 lists the percentage of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids in some common dietary fats and oils. This table compares human depot (storage) fat with butter and margarines, then with several vegetable oils. 

Several lines of evidence suggest that oxidatively modified LDL plays an important role in the development of atherosclerosis. Oxidative modification of LDL involves peroxidation of PUFAs. LDL particles enriched in PUFAs have been shown to be more susceptive to oxidative modification compared to LDL particles rich in monounsaturated fatty acids. Others have also suggested that a diet high in PUFAs may overwhelm the antioxidant defenses of cells. In particular, studies have shown that LA-enriched LDL is more prone to in vitro oxidation than oleic acid-enriched LDL. Concern also remains with... 

In the event that polyunsaturates are foimd to be the best source of fat, with the goal of reducing atherosclerosis, then safflower oil may be the oil of choice. Presently, it is recommended to replace saturated fats with a mixture of fats containing monounsaturates and PUFAs. One can see, for example, that at least 80% of the fatty acids of com oil, canola oil, soybean oil, olive oil, and safflower oil occur as the recommended fatty acids (monos and PUFAs). 

A fat content of 20-35% is strongly recommended in the 2005 dietary guidelines for Americans released by the U.S. Department of Health and Human Services. The fat in today s diet is about 40% saturated, 40% monounsaturated, and 20% polyunsaturated. Lowering the saturated and monounsaturated fat and raising the polyunsaturated fat content of the diet is also strongly recommended. What is the basis for these recommendations Heart disease is the primary cause of death in the United States (Section 17.1), and atherosclerosis, the buildup of fatty deposits called plaque on the inner walls of arteries, reduces the flow of hlood to the heart. If a coronary artery is blocked by plaque, a heart attack occurs as a result of the reduced blood flow carrying oxygen to the heart. About 98% of all heart attack victims have atherosclerosis, and the major components of atherosclerotic plaque are saturated fatty acids and cholesterol. 

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