Lichtenstein (2003) states that 15 million deaths in the late 1990s could be attributed to cardiovascular disease. The American Heart Association has pointed out that coronary heart disease and the related cardiovascular disease is the number-one killer in the US, accounting for almost one in two deaths among Americans and more deaths than are caused by all the forms of cancer combined. The impact on disability and the attendant economic loss are enormous.
Atherosclerosis (‘hardening of the arteries’) is the term used to describe a number of pathological events occurring in arteries and which are responsible for coronary heart disease, stroke and diseases of the peripheral circulatory system (Fisher 1991). Atheroma (from the Greek ather = porridge) comprises deposits of fatty material on the walls of arteries – a material comprising cholesterol, triglycerides, brous tissue and red blood cells. As it builds it restricts blood ow and if this is in the coronary artery then heart attack and death may follow, as the heart muscle does not receive suf cient oxygen. Atheroma has also been associated with the development of cataracts, macular degeneration in the retina and the development of cancers (Emerit et al. 1991; Tunick et al. 1994). If the atheroma accumulation (plaque) is ruptured a blood clot may form which not only can accelerate the blockage of the artery concerned but also may break loose and plug another artery, increasing the risk of heart attack or, if the newly blocked artery is in the brain, a stroke.
Plainly, the intake of saturated fats and cholesterol increases the risk, although it must be realised that four- fths of the cholesterol is made in our bodies and does not come through the diet. The quantity of cholesterol produced is increased in proportion to the level of saturated fatty acids in the diet (polyunsaturated fatty acids reduce blood cholesterol), and also the trans saturated fatty acids, i.e. those that are produced industrially by catalytic hydrogenation (Krisetherton 1995). High sugar intake can lead to high formation of saturated fats in the body. Indeed, any imbalance in metabolism such that there is an excess of calories over those needed to sustain the body will lead to an accumulation of fat. Obesity, hypertension, diabetes, sedentary living and the use of cigarettes all increase the risk of atherosclerosis.
As cholesterol and other lipids such as the triglycerides are insoluble in aqueous systems, they are transported through the body by combination with proteins, as lipoproteins. The principal carrier of cholesterol is low-density lipoprotein (LDL) and there is a strong positive correlation between its level and the risk of atherosclerosis. Hence LDL is frequently referred to as ‘bad cholesterol’. A lower percentage (20–30%) of the blood cholesterol is in the form of high-density
lipoprotein (HDL), which is responsible for transporting cholesterol away from the arteries to the liver where it is metabolised. This role has caused HDL to be named ‘good cholesterol’, such that high levels of HDL appear to afford protection against heart attack. Thus there is an inverse correlation between levels of HDL and atherosclerosis.
Atherosclerosis (‘hardening of the arteries’) is the term used to describe a number of pathological events occurring in arteries and which are responsible for coronary heart disease, stroke and diseases of the peripheral circulatory system (Fisher 1991). Atheroma (from the Greek ather = porridge) comprises deposits of fatty material on the walls of arteries – a material comprising cholesterol, triglycerides, brous tissue and red blood cells. As it builds it restricts blood ow and if this is in the coronary artery then heart attack and death may follow, as the heart muscle does not receive suf cient oxygen. Atheroma has also been associated with the development of cataracts, macular degeneration in the retina and the development of cancers (Emerit et al. 1991; Tunick et al. 1994). If the atheroma accumulation (plaque) is ruptured a blood clot may form which not only can accelerate the blockage of the artery concerned but also may break loose and plug another artery, increasing the risk of heart attack or, if the newly blocked artery is in the brain, a stroke.
Plainly, the intake of saturated fats and cholesterol increases the risk, although it must be realised that four- fths of the cholesterol is made in our bodies and does not come through the diet. The quantity of cholesterol produced is increased in proportion to the level of saturated fatty acids in the diet (polyunsaturated fatty acids reduce blood cholesterol), and also the trans saturated fatty acids, i.e. those that are produced industrially by catalytic hydrogenation (Krisetherton 1995). High sugar intake can lead to high formation of saturated fats in the body. Indeed, any imbalance in metabolism such that there is an excess of calories over those needed to sustain the body will lead to an accumulation of fat. Obesity, hypertension, diabetes, sedentary living and the use of cigarettes all increase the risk of atherosclerosis.
As cholesterol and other lipids such as the triglycerides are insoluble in aqueous systems, they are transported through the body by combination with proteins, as lipoproteins. The principal carrier of cholesterol is low-density lipoprotein (LDL) and there is a strong positive correlation between its level and the risk of atherosclerosis. Hence LDL is frequently referred to as ‘bad cholesterol’. A lower percentage (20–30%) of the blood cholesterol is in the form of high-density
lipoprotein (HDL), which is responsible for transporting cholesterol away from the arteries to the liver where it is metabolised. This role has caused HDL to be named ‘good cholesterol’, such that high levels of HDL appear to afford protection against heart attack. Thus there is an inverse correlation between levels of HDL and atherosclerosis.
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