Role of Butterfat in Nutrition and in Atherosclerosis: A Review

The role of butterfat in nutrition and in atherosclerosis is discussed in the light of its chemical and nutritional properties, its importance in health, and the transitory evidence for the dietary linkage of fat with heart disease.The triglyceride and fatty acid composition of butterfat is structurally different from other edible fats.This difference contributes to the superior nutritional value of thermally oxidized butterfat.It is emphasized that the total caloric intake and the ratio of dietary protein to dietary fat may be more important in determining serum cholesterol levels than the intake of the so-called soft and hard fats.Editor.Comparative growth studies under standardized conditions have served as a classical means of measuring the nutritive value of fats (17).However, since high-fat diets have been used as the most successful means for inducing atherosclerosis in animals (31), another criterion for judging the nutritive value of fats seems to have become available.In fact, a decrease in the consumption of dietary calories from fat, and the substitution of "soft" fats, such as corn oil, for "hard" fats such as butterfat, have been suggested as the best means for preventing atherosclerosis and coronary heart disease (33).In order to evaluate the role of butterfat in nutrition, and its role ill atherosclerosis, three major factors will be considered in the present discussion:(i) a comparison of the chemical and nutritional characteristics of butterfat with those of other fats, (2) the vital role that dietary fats play in good nutrition and human health, and (3) the incomplete data on which practical dietary information is linked with heart disease. CHEI~ICAL COMPOSITION OF BUTTERFAT AS CO~][PARED WITH OTHER FATSThe term "fat" usually has been applied to a wide variety of fat-soluble, or "lipid," materials.However, the component of greatest nutritional interest in this discussion involves the portion known chemically as a triglyceride.A triglyceride contains glycerol and three parts, or moles, of fatty acids.The proportion of various triglycerides and the mixed fatty acid composition of an edible fat determine its physical state and stability and, as has been shown recently (28), are important factors in its nutritional value.A fat with a large proportion of trisaturated glyeerides (Table 1), as beef fat, hydrogenated coconut oil, and butterfat, is a solid or hard fat at room temperature, and is more stable towards heat than an oil or soft fat, such as safflower or corn oil, which contains a large proportion of triunsaturated or diunsaturated glycerides.