Saturated fat

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Types of fats in food
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Saturated fat is fat that consists of triglycerides containing only saturated fatty acids.

Contents

[edit] Explanation

Fat that occurs naturally in living matter contains varying proportions of saturated and unsaturated fat. Foods that contain a high proportion of saturated fat are butter, ghee, suet, tallow, lard, coconut oil, cottonseed oil, and palm kernel oil, dairy products (especially cream and cheese), meat, chocolate, and some prepared foods[1].

There are several kinds of naturally occurring saturated fatty acids, their only difference being the number of carbon atoms - from 1 to 24. Saturated fatty acids have no double bonds between the carbon atoms of the fatty acid chain; hence, they are fully saturated with hydrogen atoms.

While nutrition labels usually lump them together, the saturated fatty acids appear in different proportions among food groups. Lauric and myristic acids are most commonly found in "tropical" oils (e.g. palm kernel, coconut) and dairy products. The saturated fat in meat, eggs, chocolate and nuts is primarily palmitic and stearic acid.

saturated fat profile of common foods (percentage of total fat)[2]
Food Lauric acid Myristic acid Palmitic acid Stearic acid
Coconut oil 47% 18% 9% 3%
Butter 3% 11% 29% 13%
Ground beef 0% 4% 26% 15%
Dark chocolate 0% 0% 34% 43%
Salmon 0% 1% 29% 3%
Eggs 0% 0% 27% 10%
Cashews 2% 1% 10% 7%
Soybean oil 0% 0% 11% 4%

[edit] Examples of saturated fatty acids

Some common examples of fatty acids are:

[edit] Health issues

The relationship between dietary fats and CVD, especially coronary heart disease, has been extensively investigated, with strong and consistent associations emerging from a wide body of evidence accrued from animal experiments, as well as observational studies, clinical trials and metabolic studies conducted in diverse human populations...Saturated fatty acids raise total and low-density lipoprotein (LDL) cholesterol...The most effective replacement for saturated fatty acids in terms of coronary heart disease outcome are polyunsaturated fatty acids, especially linoleic acid. This finding is supported by the results of several large randomized clinical trials, in which replacement of saturated and trans fatty acids by polyunsaturated vegetable oils lowered coronary heart disease risk.

– World Health Organization, Population nutrient intake goals for preventing diet-related chronic diseases,5.4.4

Diets high in saturated fat are correlated with an increased incidence of atherosclerosis and coronary heart disease according to a number of studies, both African green monkeys[3] and human.[4][5][6][7] Some studies have suggested that diets high in saturated fat increase the risk of heart disease and stroke. Epidemiological studies have found that those whose diets are high in saturated fatty acids, including lauric, myristic, palmitic, and stearic acid, had a higher prevalence of coronary heart disease.[8][9][10][11] Additionally, controlled experimental studies have found that people consuming high saturated fat diets experience negative cholesterol profile changes.[4][12][13][14] A 2003 meta-analysis published in the American Journal of Clinical Nutrition concluded that diets high in saturated fat negatively affected cholesterol profiles — predictors of a heart attack and other cardiovascular diseases.[15]

Experiments in which subjects were randomly assigned to either a control or Mediterranean diet (which replaces saturated fat with mono and polyunsaturated fat) showed a significantly decreased likelihood of suffering a second heart attack, cardiac death, heart failure or stroke.[16][17]

Epidemiological studies of heart disease have implicated the four major saturated fatty acids to varying degrees. The World Health Organization has determined that there is "convincing" evidence that myristic and palmitic acid intake increases the probability, "possible" risk from lauric acid, and no increased risk at all from stearic acid consumption.[18]

In a study published in 2001, erythrocyte membrane oleic and monounsaturated fatty acid content was positively associated with breast cancer risk in postmenopausal women, while no association was shown between saturated fatty acids and breast cancer risk. Enzyme Δ9-desaturase catalyzes the conversion of stearic acid to oleic acid: there is a negative correlation between erythrocyte membrane oleic acid and dietary polyunsaturated fatty acids. Inverse relationship between Saturation Index (ratio of membrane stearic to oleic acid) and breast cancer risk could also be related to hormonal and metabolic factors and to interactions between them, as well as to dietary factors.[19]

[edit] Dietary recommendations

A 2004 statement released by the Centers for Disease Control (CDC) determined that "Americans need to continue working to reduce saturated fat intake..." [20] Additionally, reviews by the American Heart Association led the Association to recommend reducing saturated fat intake to less than 7% of total calories according to its 2006 recommendations.[21] [22] This concurs with similar conclusions made by the World Health Organization (WHO) and the US Department of Health and Human Services, both of which determined that reduction in saturated fat consumption would positively affect health and reduce the prevalence of heart disease.[23][15] [24]

The World Health Organization (WHO) has concluded that saturated fats negatively affect cholesterol profiles, predisposing individuals to heart disease, and recommends avoiding saturated fats in order to reduce the risk of a cardiovascular disease. [25] [26]

[edit] Contrary research

 The relevance of particular information in (or previously in) this article or section is disputed.
The information may have been removed or included by an editor as a result.
Please see discussion on the talk page considering whether its inclusion is warranted.(March 2008)
See also: Lipid hypothesis
  • A 3-year study of 235 postmenopausal women conducted by Mozaffarian et al was released in 2004. The study subjects all had established coronary artery disease. Most were hypertensive and many had diabetes (19–31%). Their body mass index ranged from 29 to 30 and their lipid profile indicated combined hyperlipidemia. These combined characteristics are consistent with metabolic syndrome. Coronary angiography was employed to examine 2,243 coronary artery segments; once at the start of the study and once more at its conclusion. The study concluded that "in postmenopausal women with relatively low total fat intake, a greater saturated fat intake is associated with less progression of coronary atherosclerosis." The same study revealed similarly surprising results when it was disclosed that a greater consumption of polyunsaturated oils "was also associated with greater progression of atherosclerosis".[27] [28][29]
  • A study of 297 acute MI cases in Portuguese males, published in February of 2007, concluded that, "Total fat intake, lauric acid, palmitic acid, and oleic acid were inversely associated with acute MI" and that, "Low intake of total fat and lauric acid from dairy products was related to acute MI". The researchers also stated, in revealing the results of this study, that "some prospective studies show that replacing saturated fat with unsaturated fat is more effective in lowering CHD risk than reducing total fat consumption".[30]
  • Fulani of northern Nigeria get around 25% of energy from saturated fat, yet their lipid profile is indicative of a low risk of cardiovascular disease. This finding is likely due to their high activity level and their low total energy intake.[31]
  • A 2004 article in The American Journal of Clinical Nutrition raised the possibility that the supposed causal relationship between saturated fats and heart disease may actually be a statistical mistake because of the greater precision with which saturated fats have been measured.[32]

[edit] Molecular description

Two-dimensional representation of the saturated fatty acid myristic acid.
Two-dimensional representation of the saturated fatty acid myristic acid.
A space-filling model of the saturated fatty acid myristic acid.
A space-filling model of the saturated fatty acid myristic acid.


[edit] See also

[edit] References

  1. ^ Saturated fat food sources
  2. ^ U.S. Department of Agriculture, Agricultural Research Service. 2007. USDA National Nutrient Database for Standard Reference, Release 20. Nutrient Data Laboratory Home Page
  3. ^ MS Wolfe, JK Sawyer, TM Morgan, BC Bullock and LL Rudel Dietary polyunsaturated fat decreases coronary artery atherosclerosis in a pediatric-aged population of African green monkeys Arteriosclerosis and Thrombosis Vol 14, 587–597
  4. ^ a b Lapinleimu H, Viikari J, Jokinen E, Salo P, Routi T, Leino A, Ronnemaa T, Seppanen R, Valimaki I, Simell O. Prospective randomised trial in 1062 infants of diet low in saturated fat and cholesterol Lancet 1995 Feb 25;345(8948):471–6
  5. ^ Francisco Fuentes; José López-Miranda; Elias Sánchez; Francisco Sánchez; José Paez; Elier Paz-Rojas; Carmen Marín; Purificación Gómez; José Jimenez-Perepérez; José M. Ordovás,; and Francisco Pérez-Jiménez Mediterranean and Low-Fat Diets Improve Endothelial Function in Hypercholesterolemic Men Annals of Internal Medicine 19 June 2001, Volume 134, Issue 12, pp. 1115–1119
  6. ^ Rivellese AA, Maffettone A, Vessby B, Uusitupa M, Hermansen K, Berglund L, Louheranta A, Meyer BJ, Riccardi G Effects of dietary saturated, monounsaturated and n-3 fatty acids on fasting lipoproteins, LDL size and post-prandial lipid metabolism in healthy subjects Atherosclerosis 2003 Mar;167(1):149–58
  7. ^ Frank B. Hu, M.D., Meir J. Stampfer, M.D., JoAnn E. Manson, M.D., Eric Rimm, Sc.D., Graham A. Colditz, M.D., Bernard A. Rosner, Ph.D., Charles H. Hennekens, M.D., and Walter C. Willett, M.D. Dietary Fat Intake and the Risk of Coronary Heart Disease in Women N Engl J Med 1998 Volume 337:1491–1499 November 20, 1997
  8. ^ Kromhout D, Menotti A, Bloemberg B, Aravanis C, Blackburn H, Buzina R, Dontas AS, Fidanza F, Giampaoli S, Jansen A, et al Dietary saturated and trans fatty acids and cholesterol and 25-year mortality from coronary heart disease: the Seven Countries Study Prev Med 1995 May;24(3):308–15
  9. ^ Frank B Hu, Meir J Stampfer, JoAnn E Manson, Alberto Ascherio, Graham A Colditz, Frank E Speizer, Charles H Hennekens, and Walter C Willett Dietary saturated fats and their food sources in relation to the risk of coronary heart disease in women Am J Clin Nutr 1999;70:1001–8
  10. ^ Coronary heart disease in seven countries
  11. ^ Beegom R, Singh RB. Association of higher saturated fat intake with higher risk of hypertension in an urban population of Trivandrum in south India Int J Cardiol 1997 Jan 3;58(1):63–70
  12. ^ Hanne Müller, Anja S. Lindman, Anne Lise Brantsæter, and Jan I. Pedersen The Serum LDL/HDL Cholesterol Ratio Is Influenced More Favorably by Exchanging Saturated with Unsaturated Fat Than by Reducing Saturated Fat in the Diet of Women The American Society for Nutritional Sciences J. Nutr 133:78–83, January 2003
  13. ^ Shanthi Mendis, U. Samarajeewa and R. O. Thattil Coconut fat and serum lipoproteins: effects of partial replacement with unsaturated fats British Journal of Nutrition Volume 85, Number 5, May 2001, pp. 583–589(7)
  14. ^ M Abbey, M Noakes, GB Belling and PJ Nestel Partial replacement of saturated fatty acids with almonds or walnuts lowers total plasma cholesterol and low-density-lipoprotein cholesterol American Journal of Clinical Nutrition Vol 59, 995–999
  15. ^ a b U.S. Department of Health and Human Services U.S. Department of Agriculture Dietary Guidelines for Americans 2005
  16. ^ http://www.circ.ahajournals.org/cgi/reprint/99/6/779.pdf
  17. ^ http://www.aims.ubc.ca/home/modules/conference/2005/med_diet_study_1994.pdf
  18. ^ World Health Organization Disease-specific recommendations
  19. ^ Valeria Pala, Vittorio Krogh, Paola Muti, Véronique Chajès, Elio Riboli, Andrea Micheli, Mitra Saadatian, Sabina Sieri, Franco Berrino (2001). "Erythrocyte Membrane Fatty Acids and Subsequent Breast Cancer: a Prospective Italian Study". JNCL 93. 
  20. ^ Trends in Intake of Energy, Protein, Carbohydrate, Fat, and Saturated Fat — United States, 1971–2000
  21. ^ Alice H. Lichtenstein, Lawrence J. Appel, Michael Brands, Mercedes Carnethon, Stephen Daniels, Harold A. Franch, Barry Franklin, Penny Kris-Etherton, William S. Harris, Barbara Howard, Njeri Karanja, Michael Lefevre, Lawrence Rudel, Frank Sacks, Linda Van Horn, Mary Winston, Judith Wylie-Rosett Diet and Lifestyle Recommendations Revision 2006: A Scientific Statement From the American Heart Association Nutrition Committee Circulation 2006;114:82-96
  22. ^ Ole Faergeman, David A. Wood, Michael Alderman, John Horgan, Philip Home, Sidney C. Smith, Jr, Rod Jackson, Thomas A. Pearson, Valentin Fuster, Salim Yusuf, Marilyn Hunn and Scott M. Grundy Principles for National and Regional Guidelines on Cardiovascular Disease Prevention: A Scientific Statement From the World Heart and Stroke Forum Circulation 2004;109;3112-3121 DOI: 10.1161/01.CIR.0000133427.35111.67
  23. ^ World Health Organization Diet, Nutrition and the Prevention of Chronic Diseases
  24. ^ U.S. Department of Health and Human Services Dietary Guidelines for Americans 2005
  25. ^ World Health Organization Risk factor: lipids
  26. ^ World Health Organization Prevention: personal choices and actions
  27. ^ 'Surprising' data: saturated fat may slow atherosclerotic progression in postmenopausal women, OB/GYN News, July 2004
  28. ^ Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women American Journal of Clinical Nutrition, Vol. 80, No. 5, 1175-1184, November 2004
  29. ^ Saturated fat prevents coronary artery disease? An American paradox American Journal of Clinical Nutrition, Vol. 80, No. 5, 1102-1103, November 2004
  30. ^ Risk of myocardial infarction and intake and adipose tissue composition of fatty acids, Nutrition Research Newsletter, March 2007 - Carla Lopes, Antti Aro, Ana Azevedo, et al. Intake and Adipose Tissue Composition of Fatty Acids and Risk of Myocardial Infarction in a Male Portuguese Community Sample. JADA;107:276-286 (February 2007)
  31. ^ Glew RH, Williams M, Conn CA, et al (2001). "Cardiovascular disease risk factors and diet of Fulani pastoralists of northern Nigeria". Am. J. Clin. Nutr. 74 (6): 730–6. PMID 11722953. 
  32. ^ Saturated fat prevents coronary artery disease? An American paradox