Saturated Fats, Cholesterol, and Heart Disease

We hear a lot these days about the relationships between saturated fats, cholesterol, and heart disease. What are the facts It s well established that a diet rich in saturated animal fats often leads to an increase in blood serum cholesterol, particularly in sedentary, overweight people. Conversely, a diet lower in saturated fats and higher in polyunsaturated fats leads to a lower serum cholesterol level. Studies have shown that a serum cholesterol level greater than 240 mg/dL (a desirable value is 200 mg/dL) is correlated with an increased incidence of coronary artery disease, in which cholesterol deposits build up on the inner walls of coronary arteries, blocking the flow of blood to the heart muscles. 

A better indication of a person s risk of heart disease comes from a measurement of blood lipoprotein levels. Lipoproteins are complex molecules with both lipid and protein parts that transport lipids through the body. They can be divided into three types according to density, as shown in Table 23.3. Very-low-density lipoproteins (VLDLs) act primarily as carriers of triglycerides from the intestines 

As a rule of thumb, a person s risk drops about 25% for each increase of 5 mg/dL in HDL concentration. Normal values are about 45 mg/dL for men and 55 mg/dL for women, perhaps explaining why premenopausal women appear to be somewhat less susceptible than men to heart disease. 

Name Density (g/mL) % Lipid % Protein Optimal (mg/dL) Poor (mg/dL) 

It s hard to resist, but a high intake of saturated animal fat doesn t do much foryour cholesterol level. This marbled Kobe beef costs Sioo/lb. 

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Focus On... Saturated Fats, Cholesterol, and Heart Disease 1090... 

Nutrition. Fats and oils are recognized as important nutrients for both humans and animals because they provide a concentrated source of energy, contain essential fatty acids, and serve as carriers for fat-soluble vitamins. Research studies have also indicated a relationship between saturated fats, cholesterol, and trans-isomers and the incidence of coronary heart disease. In many cases, shortening functionality can be maintained with formulations limiting cholesterol, the identified saturated fatty acids, and tran -isomers. Shortening formulation can also aid in reductions of fat consumption by development of more effective products to reduce the levels required to produce the desired functionality and finished product quality. 

The relation between blood levels of cholesterol and heart disease is well established. The more saturated fats and cholesterol in the diet, the higher the blood cholesterol is likely to be. Cholesterol, a lipid, has a waxy consistency, so to be transported in the bloodstream it must bond to a more water-soluble substance. Cholesterol combines with proteins to form lipoproteins, which are water soluble because of their many —NHj and —COO ions. About 65 % of the cholesterol in the blood is carried by low-density lipoproteins (LDLs), whereas about 25% is carried by high-density lipoproteins (HDLs). (The density difference is caused by the ratios of lipid to protein.)... 

Most experts recommend a food-based dietary approach to lower plasma cholesterol levels. Indeed, the FDA begins all claims about the role of diet and heart disease with ...a diet low in saturated fat and cholesterol.... Such a diet normally would include many vegetables, fruits, and limits on animal products and can also include 25 g of soy protein along with 3 to 6 g of soluble fiber. However, the role of such advice should be evaluated in terms of compliance with the advice as well as the potential efficacy of the recommended nutrition changes. The experimental evidence supporting dietary approaches to lower plasma LDL-C concentrations comes from controlled feeding trials devoid of many practical barriers that are likely to reduce the effectiveness of prescribed diets in real-life sitnations. Farther, the efficacy of recommended diets depends on compliance and the extent that... 

We are concerned about what types of dietary fat we should consume. We hear frequently about the amounts of saturated fats and cholesterol in our diets because a strong correlation has been found between these lipids and heart disease. Large quantities of dietary saturated fats may also predispose an individual to colon, esophageal, stomach, and breast cancers. As a result, we are advised to reduce our intake of cholesterol and saturated fats. 

Polyunsaturated vs. Saturated Fats. Most vegetable oils, with the exception of cocoa butter, coconut oil, and the palm oils, are more unsaturated (they have higher iodine numbers) than most fats from animals. Marine animals and fish may also be rich in unsaturated fats. Also, vegetable oils are free of cholesterol, which is suspected of contributing to the development of atherosclerosis and heart disease, when excessive amounts of the sterol are consumed by susceptible people over long periods of time. Furthermore, the substitution of substantial amounts of vegetable oils for saturated... 

Of all cardiovascular diseases, CHD is the leading cause of death for both men and women in the U.S., causing one in five deaths in 2003. Approximately every 29 seconds someone in the U.S. suffers from a CHD-related event, and approximately every minute someone dies from such an event. In addition, it is predicted that 1.2 million Americans will have a new or recurrent coronary attack in 2006, and the estimated direct and indirect cost of CHD for 2006 is 142.5 billion. After the age of 40, the hfetime risk of having coronary heart disease is 49% for men and 32% for women. Risks for CHD include both modifiable and nonmodifiable factors, including male gender, increasing age, overweight/obesity, saturated fat intake, and elevated plasma cholesterol levels. 

Soybeans contain about 40% protein (dry basis) and are rich in amino acids lysine and threonine. However, low content of the essential amino acid L-methionine hmits nutritive value of soy protein. Globulins, referred to as glycinin and conglycinin, are the most abundant protein types in soybeans. Health benefits of soybean proteins have been studied extensively. Positive effects of soybean proteins on hypertension and heart disease, osteoporosis, bone health and certain cancers have been reported (Friedman and Brandon, 2001). The US Food and Drug Administration (FDA) has authorized a health claim on the role of soy protein in reducing risk of coronary heart disease. The FDA rule permits a statement on the soybean containing product labels indicating that Diets low in saturated fat and cholesterol that include 25 g of soy protein a day may reduce the risk of heart disease (FDA, 1999). 

Most of the other components of the analyzed diets - total calories, total fat, mono-unsaturated fat, polyunsaturated fat, total protein - were not significantly related to serum cholesterol levels or coronary heart disease incidence rates of the cohorts. Dietary cholesterol was not systematically evaluated. Sucrose intake - significantly correlated with saturated fat intake - was significantly correlated with coronary heart disease incidence (r = 0.78). However, when this analysis was extended beyond simple correlation, with consideration simultaneously to both saturated fat and sucrose, the association between saturated fat intake and CHD incidence remained highly significant statistically, that between sucrose and CHD incidence became insignificant (14). 

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. 

Because unsaturated fats are now recognized as being more beneficial to health than saturated fats, American diets have changed to include more unsaturated fats and less saturated fatty acids. This change is a response to research that indicates that atherosclerosis and heart disease are associated with high levels of fats in the diet. However, the Inuit people of Alaska have a diet with high levels of unsaturated fats as well as high levels of blood cholesterol, but a very low occurrence of atherosclerosis and heart attacks. The fats in the Inuit diet are primarily unsaturated fats from fish, rather than from land animals. 

Lipoproteins and their associated apoproteins are strong predictors of the risk of coronary heart disease (CHD). Concentrations of total cholesterol, low-density lipoproteins (LDL), and apoprotein B are positively correlated with CHD risk high-density lipoprotein (HDL) and apoprotein A1 concentrations are negatively correlated. Controlled dietary trials have now demonstrated that the total saturated fat content and the type of saturated fatty acid in the diet affect serum lipid and lipoprotein levels. 

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