Danger of Saturated Fat - Research Paper Example

?SATURATED FAT IS NOT SO BAD FOR HEALTH One-quarter of what you eat keeps you alive. The other three-quarters keep your doctor alive. Hieroglyph found in an ancient Egyptian tomb Human body and its nutrition share a similarity in composition, though the relative proportions of the substances forming the two vary. The source of body fat is lipids that are stored in the living body as triglycerides, cholesterols and phospholipids. The structure of triglycerides comprises of a glycerol backbone to which are attached three fatty acids (figure 1). Triglycerides are important sources of nutrition, energy and insulation (Britannicaonline,; Medic on web,). WHAT IS SATURATED FAT? The triglycerides forming the fat vary with respect to the nature of fatty acids, i.e. the length and the saturation levels of fatty acids rendering the fat saturated or unsaturated. Fat in body is a mixture of the two forms of fat; however the ratios of two vary. Thus saturated fat refers to fat mixture with lower number of double bonds, while unsaturated fat refers to fat mixture with higher number of double bonds. Figure 1: (medic on web, 2011) Figure 2: Saturated and Unsaturated Fats (yellowtang.org) Saturation of a chemical bond refers to the presence of single bonds exclusively in a molecule. In saturated fats, all the bonds between the carbon and hydrogen of fatty acids comprising the fat molecule are single bonds. Further the since the single bonds allow close packing of the molecules, with van der Waals forces providing intermolecular binding; saturated fats are solids. In contrast unsaturated fats are characterized by the presence of at least one double bond. The comparative rigidity of unsaturated bonds, does not allow unsaturated fats to pack as closely. Hence they have lower melting points. Thus a higher proportion of unsaturated fats gives the fat mixture a lower melting point or makes it liquid. The liquid fat is referred to as oil. Another category of dietary fat intake includes trans fat, which is vegetable fat with unsaturated fatty acids that have been made to artificially undergo hydrogenation to make them partially unsaturated trans isomers (Scanes, ch1). Saturated fats are present in animal products such as butter, cheese, whole milk, ice cream, cream, and fatty meats and in certain vegetable oils -- coconut, palm, and palm kernel oils (Dietitians of Canada). SIGNIFICANCE OF SATURATED FAT IN DIET It has been common belief and supported by studies that saturated fats have higher probability of blocking the blood vessels and hence may cause cardiovascular diseases. In contrast a diet comprising of polyunsaturated fats may be healthier (Pilling, Ch1). A less than 10% dietary intake of saturated fats is recommended by Dietitians of Canada and the American Dietetic Association; a higher proportion raising the risk of accumulation of LDL (low density lipoproteins) cholesterol levels (Dietitians of Canada). EARLY STUDIES One of the major early evidences correlating the levels of saturated fats in diet with development of coronary heart diseases (CHDs) was provided by a seven country study involving 12763 men examined between 1958 and 1964. During the 10 and 15 year follow up a high positive correlation was established between baseline saturated fat intake and death due to CHD; and inverse relation between the latter and dietary intake of monounsaturated fatty acids. Further a correlation was also established between mean saturated fatty acid intake and overall level of total serum cholesterol. The results from this study led to a series of researches exploring the relation between dietary fat and CHD. Most of these studies reported that risk of CHD lowers when saturated fats are replaced by unsaturated fats leading to the development of the concept of good fat, i.e. unsaturated fat and bad fat, i.e. saturated fats (Skeaff & Miller, 173). REVIEW OF CURRENT LITERATURE In the studies conducted during the last decade the above results have been challenged. A study conducted by Mozaffarian and associates (2004) established a relationship between saturated fat and risk of CHD opposite to that reported earlier. Based on quantitative angiography, they established that saturated fats are associated with lower progression of CHDs. To explain this paradox, it was stated that saturated fats are more precisely measured compared to total fat. Hence during statistical analyses, they associate more strongly with the outcome variable; in this case CHD; even though other factors such as total fat or carbohydrate may be the ones physiologically more associated with the development of CHDs. This study therefore challenges the long established categorization of good fat/ bad fat (Knopp & Retzlaff, 1102). Another meta-analysis of 21 studies using random effects model derived composite data for relative risk estimates for CHD, stroke and cardiovascular diseases (CVDs) and its correlation to dietary fat. The study involving 347,747 subjects with a follow up of 5-23 years, reported 11,006 CHD or stroke cases. No strong correlation was reported between the risks of CHD, CVD and stroke; and saturated fat intake (Siri-Tarino et al.). CONTROVERSY Healthy eating is a vague concept; time, culture and location dependent. The established norm of low fat diet being a healthy diet is as controversial as the alleged ‘fact’ that saturated fats raise the risk of heart diseases. Though saturated fats raise LDL cholesterol, their impact is lowered due to the fact that these are larger LDL particles that are now established to be less of a risk than smaller ones (Berkeley). Further the risks are highly dependent on genetic factors, body weight, gender, and the source of saturated fats (Berkeley). Recalling the case of the Masai men, a nomadic tribe of Kenya and Tanzania; who lived on a diet of 60% fat, half of it being saturated fats. During a study conducted by George Mann in 1960, these men were found to have significantly low levels of cholesterol and were almost free of heart diseases. Formerly this trait in Masai men was attributed to genetic factors, but subsequent studies on Masai men who had migrated to Nairobi and were on a modern diet showed that these men had significantly high cholesterol levels. Similar observations were made from investigations on another Kenyan tribe, Samburu. Both of these studies refuted the reports that had been accepted as ‘facts’; that saturated fats are responsible for increase in LDL cholesterol and contributed to development of CVDs and CHDs (Teicholz et al.). Recent studies have proved that saturated fats are not that bad for health as they have been repeatedly established to be. In fact they are highly useful to living body. Under stress conditions, heart derives additional energy from the saturated fat reserves in its vicinity. Further 60% of the brain tissue is made of saturated fats. Saturated fats are integral components of each cell of body with the cell membrane formed almost entirely of these. They also play significant roles in the structural development of body (Huff). CONCLUSION: SATURATED FAT MAY NOT BE BAD FOR HEALTH Saturated fats may not be good; but neither are they bad. The important issue is what we are using to replace our saturated fat intake. Using trans fat instead of saturated fat from sources such as white bread, pasta etc lowers the HDL (high density lipoproteins) cholesterol levels and raises the levels of small particles of LDL cholesterol. But switching to polyunsaturated fats may lower risk of the heart diseases and improve cholesterol levels (Berkeley). High fat intake and high levels of saturated fats in diet have been associated with high risk of development of heart diseases, however categorizing them as “bad fat” or stating that the any level of intake of saturated fat is harmful is an inaccurate generalization. It is based on an oversimplified and unscientific description of the mechanism of interaction of fat with the body. A fact which can only be considered as a belief based on superstition. The truth is that saturated fats are vital biomolecules. WORKS CITED 1. Berkeley, U. C. "Saturated Fat: Not Quite So Bad After All?" June 2010. Wellness letter. November 2011 . 2. "Dietary fats." 2011. Dietitians of Canada. November 2011 . 3. Huff, E. A. "Is saturated fat really bad for you?" October 2010. Natural news. November 2011 . 4. "Human nutrition." 2011. Encyclopaedia Brittannica. November 2011 . 5. Knopp, R. H and B. M. Retzlaff. "Saturated fat prevents coronary artery diseases? An American paradox." The American journal of clinical nutrition (2004): 1102-3. 6. "Lipids: saturated vs unsaturated." Yellow tang. November 2011 . 7. Pilling, G. Salters higher chemistry. Spain: Edelvives, 1999. 8. Scanes, C. Fundamentals of animal science. NY: Cengage learning, 2011. 9. Siri-Tarino, P. W, et al. "Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease." American journal of clinical nutrition (2010). 10. Skeaff, C. M and J. Miller. "Dietary fat and coronary heart disease: summary of evidence from prospective cohort and randomised control trials." Ann nutr metab (2009): 173-201. 11. Teicholz, N. "What if bad fat is actually good for you?" October 2007. Men's health. November 2011 . 12. "Triglycerides." April 2011. Medic on web. November 2011 . Read More