Coronary heart disease composite diets

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). 

In the 1950s, Keys and co-workers pioneered work indicating the very different effects of saturated and unsaturated dietary fats on blood cholesterol levels and, in turn, on coronary heart disease. Based on this work, the lipid hypothesis states that there is a connection between the FA composition of the diet and the cholesterol content of the blood serum, in that saturated FA increase cholesterol, while PUFA decrease it. Later, it was established that the type of fat affected the lipid level more than cholesterol in blood. Keys research has provided the basis for the recommendation that fats with a relatively low proportion of PUFA be replaced by fats and oils that are rich in PUFA. 

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