Fat and 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. 

Since then, there have been numerous studies that investigated the effect of different types and amounts of fat, individual fatty acids and other dietary components on plasma cholesterol level. It is now realized that all saturated fatty acids do not elevate plasma cholesterol levels to the same extent. The short-chain fatty acids, butyric (C4 o), caproic (C6 o), caprylic (Cs o) the medium-chain capric (Cio o) and stearic (Ci8 o) acids, 

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Ahrens, E. H., Jr. 1979. Dietary fats and coronary heart disease Unfinished business. Lancet 2, 1345-1348. 

Skeaff CM, Miller J. Dietary fat and coronary heart disease summary of evidence from prospective cohort and randomised controlled trials. Ann Nutr Metab. 2009 55 173-201. 

Various authors The cholesterol facts. A summary of the evidence relating dietary fats, serum cholesterol, and coronary heart disease. Circulation 1990 81 1721. 

The three fat fuels and their metabolism are involved directly or indirectly in diseases such as diabetes mellitus, syndrome X, obesity, atherosclerosis and coronary heart disease, which are discussed in other chapters in this book. This section considers the problems associated with high blood levels of ketone bodies and long-chain fatty acids. 

Excess fat can be located in the central abdominal area (android, upper body obesity). This fat is associated with a greater risk for hypertension, insulin resistance, diabetes, dyslipidemia, and coronary heart disease. That distributed in the lower extremities (gynoid, lower body obesity) is relatively benign, healthwise. 

LaRosa JC, Hnninghake Du, Bush D, Grundy et al. The cholesterol facts. A summary of the evidence relating dietary fats, serum cholesterol, and coronary heart disease. A joint statement by the American Heart Association and the National Heart, Lung, and Blood Institute. The Task Force on Cholesterol Issues, American Heart Association. Circulation. 1990, 8 1721-1733. 

Fraser GE. Diet and coronary heart disease beyond dietary fats and low-density-lipoprotein cholesterol. Am J Clin Nutr 1994 59 1 I I7S-I I23S. 

McKeigue, P. (1995). FndMS fatty acids and coronary heart disease lAfeighing the evidence against hardened fat. Lancel 345, 269-270. 

Among various types of fat deposition, visceral fat type obesity is one risk factor for metabolic diseases such as diabetes mellitus, hypercholesterolemia, hyperlipidemia, hypertension, and atherosclerosis. The risk of diseases such as diabetes mellitus and coronary heart disease, as well as all-cause mortality, increases in proportion to the increase in body adipose above optimal, but intra-abdominal distribution of fat in the body is associated more closely with disease risk. 

Grundy, S.M., Dietary fat at the heart of the matter. Science, 293, 801, 2001. Katan, M.B., Zock, P.L., and Mensink, R.P., Dietary oils, serum lipoproteins, and coronary heart disease. Am. J. Clin. Nutr, 61 (6 Suppl), 1368S, 1995. 

Unfortunately, the relationship between saturated fats in the human diet and the formation of cholesterol (a simple lipid, see below) plaque and coronary heart disease has been established. The dietary switch to less saturated fats is currently underway. 

It is the male pattern of upper body segment obesity that is associated with the major health risks, and in a number of studies assessment of the pattern of fat distribution by measurement of either the waist—hip ratio or the subscapular skinfold thickness (section 6.1.2.5) shows a greater correlation with the incidence of hypertension, diabetes and coronary heart disease than does BMI alone. 

Atherosclerosis and coronary heart disease. There is some evidence that a high consumption of sucrose is a factor in the development of atherosclerosis and coronary heart disease, although the evidence is less convincing than that for the effects of a high (saturated) fat intake. 

One of the most important research advances since World War II is the delineation of the chief mechanism of the etiologic effect of dietary lipid on atherogenesis. This has been the demonstration - as illustrated in the last three figures - that populations differing in habitual intake of saturated fat and cholesterol also differ markedly in serum cholesterol levels, i.e., interpopulation levels of these two sets of variables are highly correlated. So also are dietary saturated fat-cholesterol intake and coronary heart rates, and serum cholesterol level and coronary heart disease rates. 

Reduction in semm Hpids can contribute significantly to prevention of atherosclerosis. In 1985 a consensus report indicating that for every 1% reduction in semm cholesterol there is a 2% reduction in adverse effects of coronary heart disease was issued (145). Recommended semm cholesterol concentration was 200 mg/dL for individuals under 30 years of age, and individuals having concentration 240 mg/dL and LDL-cholesterol over 160 mg/dL should undertake dietary modification and possibly pharmacotherapy (146). Whereas the initial step in reducing semm cholesterol is through reduction of dietary cholesterol intake, a number of dmgs are available that can affect semm Hpid profile (see Fat substitutes). The pathway to cholesterol synthesis is shown in Figure 2. 

To date, the studies that have tried to link dietary fat to increased risk of coronary heart disease have remained ambiguous. Studies have shown that cholesterol-lowering drugs help reduce the risk of heart (45) disease, but whether a diet low in cholesterol can do the same is still questionable. While nutrition experts are debating whether a low-fat, carbohydrate-based diet is the healthiest diet for Americans, nearly all agree that the anti-fat message of the last twenty years has been oversimplified. For example, some fats and oils like those found in olive oil... 

Coronary heart disease A type of heart disease caused by narrowing of the coronary arteries that feed the heart, which needs a constant supply of oxygen and nutrients carried by the blood in the coronary arteries. When the coronary arteries become narrowed or clogged by fat and cholesterol deposits and cannot supply enough blood to the heart, CHD results. [NIH]... 

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