Saturated fats, 439 Table

Numerous experiments with mice and rats have shown that animals on high fat diets develop mammary tumors more readily than similarly treated controls on low fat diets (Tannenbaum Silverstone, 1957 Tannenbaum, 1959 Carroll Khor, 1975 Carroll, 1975). In our own studies on rats treated with 7,12-dimethylbenz(a)anthracene (DMBA), unsaturated fats increased tumor yields more than saturated fats (Table 1). However, there did not seem to be a direct correlation with essential fatty acid content since lard and olive oil were about as effective as corn oil and soybean oil, although the latter are much richer in linoleic acid (Carroll Khor, 1971). Dayton and Hashimoto (1976) reached a similar conclusion on the basis of their experiments with an oil rich in oleic acid produced by a mutant safflower. This oil was found to be as effective as normal high-linoleic safflower oil in stimulating development of mammary... 

Therapeutic lifestyle changes should be the first approach tried in all patients (Table 9—7).3 An adequate trial of TLC should be employed in all patients, but pharmacotherapy should be instituted concurrently in higher-risk patients. This includes dietary restrictions of cholesterol and saturated fats as well as regular exercise and weight reduction. In addition, therapeutic options to enhance LDL cholesterol lowering such as consumption of plant stanols/sterols (which competitively inhibit incorporation of cholesterol into micelles) and dietary fiber should be encouraged. These therapeutic options collectively may reduce LDL cholesterol by 20% to 25%. 

The objectives of dietary therapy are to progressively decrease the intake of total fat, saturated fat, and cholesterol and to achieve a desirable body weight (Table 9-4). 

High serum triglycerides (see Table 9-1) should be treated by achieving desirable body weight, consumption of a low saturated fat and cholesterol diet, regular exercise, smoking cessation, and restriction of alcohol (in selected patients). 

Polyunsaturated fatty acids are characterized by a large number of C = C double bonds in their hydrocarbon chain. Stearic acid has no C = C double bonds and therefore is not unsaturated, let alone polyunsaturated. But eleostearic acid has three C = C double bonds and thus is polyunsaturated. Polyunsaturated fatty acids are recommended in dietary programs since saturated fats are linked to a high incidence of heart disease. Of the lipids listed in Table 28-2, safflower oil has the highest percentage of unsaturated fatty acids, predominately linoleic acid, an unsaturated fatty acid with two C=C bonds. 

Humans produce about 1 gram of cholesterol daily in the liver. Dietary cholesterol is consumed through food. High cholesterol foods are associated with saturated fats and trans-fatty acids (commonly called trans fats). Dietary cholesterol comes from animal products (plants contain minute amounts of cholesterol) such as meats and dairy products. Table 26.1 shows the amount of cholesterol in common foods. 

Diets. Three basic diets were utilized (Table I), a 2% low fat diet (2% linoleic acid methyl esters), a 20% polyunsaturated fat diet containing 20% stripped corn oil, and a high saturated fat diet containing 18% coconut oil and 2% linoleic acid methyl esters to prevent an essential fatty acid deficiency (6 ). All diets were prepared to our specifications by ICN Life Sciences (Cleveland, OH) and analyzed both by ICN and our laboratory for fatty acids, antioxidants and some trace minerals. They are routinely stored in sealed plastic containers at 4°. Antioxidants when added (see Figure 2) were supplemented just prior to feeding and at 0.2% or 0.3% of the diet by weight as specified in each experiment. 

Fatty acids consist of a hydrocarbon chain with a carboxylic acid at one end. They can be classified on the basis of the length of the hydrocarbon chain (Table 2.2) and whether there are any double bonds. Trivial names of fatty acids such as butyric, lauric, oleic and palmitic acids are in common use in the food industry. A form of short-hand is used to refer to triglycerides where POS is palmitic, oleic, stearic. If the chain length is the same an unsaturated fat will always have a lower melting point. Another classification of fats that is used is in terms of the degree of unsaturation of the fatty acids. Saturated fats are fats without any double bonds. Many animal fats are saturated, but some vegetable fats, e.g. coconut oil, are saturated also. Mono-unsaturated fats include oils like olive oil but also some partially hydrogenated fats. Polyunsaturated fats have many double bonds and include sunflower oil. Because they are... 

The National Cholesterol Education Program (NCEP)-recommended steps to lower the risk of CAD, collectively referred to as the TLC, are presented in Table 8.4. These guidelines are typically used for higher-risk individuals with elevated plasma cholesterol concentrations, established cardiovascular disease, and more than one major risk factor. The TLC dietary guidelines are relatively stringent, limiting daily total and saturated fat intakes to <30% and 7% of total energy and cholesterol... 

Japanese quad exhibit greater plasma total cholesterol concentrations than rat counterparts when fed a similar, basal low-cholesterol diet (Table 1). Species differences in plasma lipids are more pronounced when fed an atherogenic diet (e.g., cholesterol/cholic acid supplemented and saturated fat-contaming diet), as evidenced by the marked elevations observed in quad plasma total cholesterol concentrations... 

The current interest in dietary fat, however, stems primarily from its implication in the origin of several chronic diseases. Interest has centered on both the amount and type of dietary fat in the development of cardiovascular disease, cancer, hypertension, and obesity. As a result, dietary recommendations in many countries call for a reduction in total fat intake, to 30% of energy, and in saturated fat intake, to less than 10% of energy. In addition, some nutrition recommendations specify recommended levels of n-6 and n-3 fatty acids in the diets. Hence, the source of fat in the diet has assumed considerable importance over the past few years. Interest in the nutritional properties of canola oil developed because of its fatty acid composition (Table 2). Canola oil is characterized by a low level of saturated fatty acids, a relatively high level of monounsaturated fatty acids, and an appreciable amount of the n-3 fatty acid ot-linolenic acid (18 3 n-3). 

Ishida et al. (74) examined gac seed oil for its fatty acid composition. The oil was determined to contain an average of 60.5% stearic acid. Palmitic and arachidic acids were two other saturated fats found in the gac seed oil, and the total percent of saturated fatty acids ranged from 60.5% to 79.2%. The most prevalent unsaturated fatty acid was hnoleic acid at 20.3%, with an interesting variety of others including palmitoleic (16 1), oleic (18 ln-9), c -vaccenic (18 ln-ll), a-linolenic acid (18 3n-3), eicosa-ll-enoic acid (20 ln-ll), and eicosa-13-enoic acid (20 ln-13) (Table 10). 

A study on diet and colon cancer was reported by W. Willett s group (Willett et at., 1990) (Table 11.3). The study examined various components of the diet, such as fiber, fat, and meat. The fiber component was divid into cereal fiber and fruit fiber. The fat component was divided into meat fat, dairy fat, saturated fat, and unsaturated fat. The meat component was divided into beef, pork, and lamb, and into rare versus well-done Styles of cooking. The body mass index, as defined in the Obesity chapter, was also recorded. The study was part of the Nurses Health Study Cohort, which was inibated in 1976 and involved 121,700 female nurses. Every 2 years, the nurses filled in a questionnaire that asked about various risk factors for disease. The questionnaire asked, for example, about 61 foods and their frequency In the diet. The foods were chosen to allow epidemiologists to make broad statements regarding the component nutrients. 

Table I. Effect of a Chronic Marginal Vitamin C Deficiency (19 Weeks on a Diet with 15% Predominantly Saturated Fat and 0.03% Cholesterol) on Blood Serum Lipids in Sated Male Guinea Pigs...

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