Coronary heart disease saturated fatty acids

Monounsaturated fats Triacylglycerols containing primarily fatty acids with one double bond are referred to as monounsaturated fat. Unsaturated fatty acids are generally derived from vegetables and fish. When substituted for saturated fatty acids in the diet, monounsaturated fats lower both total plasma cholesterol and LDL cholesterol, but increase HDLs. This ability of monounsaturated fats to favorably modify lipoprotein levels may explain, in part, the observation that Mediterranean cultures, with diets rich in olive oil (high in monounsaturated oleic acid), show a low incidence of coronary heart disease. 

By far the most telling negative nutritional aspect of milk fat is the belief that its content of saturated fatty acids and cholesterol elevate plasma cholesterol levels, which is a risk factor for coronary heart disease (CHD). During the early 1950s, it was found that the type of fat in the diet could influence plasma cholesterol level. Ahrens et al. (1957) showed that diets containing saturated fats, such as beef, lard and milk fat, produced higher plasma cholesterol levels than diets containing unsaturated fat like safflower and corn oil when they were fed under strict metabolic-ward conditions. Later, Connor (1961) reported that the level of cholesterol in the diet also influenced plasma cholesterol level. 

Trans-Isomers and Coronary Heart Disease An increased risk of developing heart disease has been linked to an intake of trans-fatty acids (223). The replacement of dietary saturated fatty acids by trans-fatty acids, for example, lowers serum HDL cholesterol and impairs endothelial function in healthy men and women (224). It also impairs flow-mediated vasodilation and decreases the activity of serum paraoxonase, which is an HDL-bound esterase that may protect against atherosclerosis (225). 

Nutrition. Fats and oils are recognized as important nutrients for both humans and animals because they provide a concentrated source of energy, contain essential fatty acids, and serve as carriers for fat-soluble vitamins. Research studies have also indicated a relationship between saturated fats, cholesterol, and trans-isomers and the incidence of coronary heart disease. In many cases, shortening functionality can be maintained with formulations limiting cholesterol, the identified saturated fatty acids, and tran -isomers. Shortening formulation can also aid in reductions of fat consumption by development of more effective products to reduce the levels required to produce the desired functionality and finished product quality. 

The consumption of fat of high saturated fatty acid content has been associated with increased risk of coronary heart disease. Traditional sunflower oil contains around 11-12% saturated fatty acids, a considerably low value among vegetable oils. Canola oil has 7% and safflower oil less than 10% of saturated fatty acids, both being strong competitors of the edible oil market. 

The typical sunflower oil composition is 66-72% linoleic acid, 12% saturated acids (palmitic and stearic), 16-20% oleic acid, and less than 1% a-linolenic acid. An increase in low-density lipoprotein cholesterol (LDL-C) and a decrease of high-density lipoprotein cholesterol (HDL-C) are believed risk factors of coronary heart disease (CHD). Diets rich in saturated fat increase plasma total and LDL-C. Traditional high-linoleic sunflower oil has always been regarded as healthy because of its high content of polyunsaturated fatty acids (PUFA) and relatively low content in saturated fatty acids. 

The physiological effects of vegetable oil are based on their fatty acid composition. Current US dietary guidelines recommend that diets contain less than 30% calories from fat, of which less than 10% is from saturated fat, 10-15% from monounsaturated acid, and 10% from polyunsaturated acids. The primary concerns with fatty acid consumption relate to two chronic diseases—coronary heart disease (CHD) and cancer. Research has shown that high levels of dietary saturated fatty acids are related to increased CHD and that dietary modification can lower plasma cholesterol. Consequent changes in cholesterol level can be predicted by the following relationship (Hegsted et al. 1993). 

Among foods with favorable fatty acid profile, nuts have received particular attention because epidemiological studies have indicated that their increased intake is associated with protection from coronary heart disease (CHD) [10-13]. The total lipid content and fatty acid composition of Brazil nut oil from different sources are listed in Table 9.2. The total lipid content of Brazil nut ranges from 60.87% to 66.71% of the whole nut. Brazil nut is low in saturated fatty adds (SFA) and high in unsaturated fatty acids. There are great variations in fatty add composition of Brazil nut from different sources. However, the available data aU indicate that their PUFA and MUFA are mainly 18 2(o6 and 18 lco9, respectively. The variation in the results from different research gronps are nonetheless... 

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. 

We have seen in Section F that the dietary factors linked with the incidence of coronary heart disease reflect complex relations that cannot be simply based on ratios of polyunsaturated to saturated fats. It is now evident that not all saturated, polyunsaturated and monounsaturated fats play the same role in nutrition, n-3 Polyunsaturated fatty acids are not particularly effective in lowering serum cholesterol, but markedly reduce serum triacylglycerols in hypertriglyceridic subjects. The recent tendency has been to make nutritional recommendations on the basis of total fat intake and on the ratio of n-6 to n-3 polyunsaturated fatty acids. Reducing n-6 polyunsaturated fatty acids may be an effective way of utilizing relatively low and more practical amounts of fish oils. 

There is strong evidence that the risk of coronary heart disease is directly related to the plasma concentration of LDL-cholesterol and inversely related to that of HDL-cholesterol, and that the risk is reduced significantly by lowering elevated serum cholesterol levels. It has been known for many years that one of the most important dietary factors regulating serum cholesterol levels is the ratio of polyunsaturated fatty acids (PUFA) to saturated fatty acids (SFA). The SFA increase and the PUFA decrease cholesterol levels, except for the trans PUFA, which have a similar effect to the SFA. A ratio of 0.5. 9 SFA PUFA is considered to be satisfactory. It is... 

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