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 acid radicals. There are several kinds of naturally occurring saturated fatty acids, which differ by the number of carbon atoms, ranging from 3 carbons (Propionic Acid) to 36 (Hexatriacontanoic acid). Saturated fatty acids have no double bonds between the carbon atoms of the fatty acid chain and are thus fully saturated with hydrogen atoms.

Fat that occurs naturally in living matter contains varying proportions of saturated and unsaturated fat. Examples of foods containing a high proportion of saturated fat include dairy products (especially cream and cheese but also butter and ghee), animal fats such as suet, tallow, lard and fatty meat, coconut oil, cottonseed oil, palm kernel oil, chocolate, and some prepared foods[1].

Serum saturated fatty acid is generally higher in smokers, alcohol drinkers and obese people.[2]

Contents

[edit] Fat profiles

While nutrition labels usually combine them, the saturated fatty acids appear in different proportions among food groups. Lauric and myristic acid radicals 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 the triglycerides of palmitic and stearic acid.

Saturated fat profile of common foods (Esterified fatty acids as percentage of total fat )[3]
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

Main article: List of saturated fatty acids

Some common examples of fatty acids:

[edit] Stable deepfry and baking medium

Merge-arrow.svg
 It has been suggested that this article or section be merged into Polyunsaturated fat. (Discuss)

Deepfry oils and baking fats that are high in saturated fats, like palm oil, tallow or lard, can withstand extreme heat (of 180-200 degrees Celsius) and is resistant to oxidation. A 2001 parallel review of 20-year dietary fat studies in the United Kingdom, the United States of America and Spain[6] concluded that polyunsaturated oils like soya, canola, sunflower and corn degrade easily to toxic compounds and trans fat when heated up. Prolonged consumption of trans fat-laden oxidized oils can lead to atherosclerosis, inflammatory joint disease and development of birth defects. The scientists also questioned global health authories’ wilful recommendation of large amounts of polyunsaturated fats into the human diet without accompanying measures to ensure the protection of these fatty acids against heat-and oxidative-degradation.

[edit] Diseases with ties to saturated fat intake

[edit] Cardiovascular diseases

Diets high in saturated fat have been correlated with an increased incidence of atherosclerosis and coronary heart disease.

Combined cholesterol and saturated fat feeding has shown an increase in cholesterol levels of African green monkeys[7], while one study with baboons showed the opposite effect on LDL cholesterol. Rudel (1995). "Dietary polyunsaturated fat modifies low-density lipoproteins and reduces atherosclerosis of nonhuman primates with high and low diet responsiveness". The American journal of clinical nutrition 62 (2): 463S–470S. PMID 7625361.  edit.

An increase in cholesterol levels has been observed in humans with an increase in saturated fat intake, such as a study of 22 hypercholesterolemic men.[8][9][10] 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 fats, including lauric, myristic, palmitic, and stearic acid, had a higher prevalence of coronary heart disease.[11][12][13][14] Additionally, controlled experimental studies have found that people consuming high saturated fat diets experience negative cholesterol profile changes.[15][16][17][18]

In 1999, volunteers were randomly assigned to either Mediterranean (which replaces saturated fat with mono and polyunsaturated fat) or a control diet showed that subjects assigned to a Mediterranean diet exhibited a significantly decreased likelihood of suffering a second heart attack, cardiac death, heart failure or stroke.[19][20]

An evaluation of data from Harvard Nurses' Health Study found that "diets lower in carbohydrate and higher in protein and fat are not associated with increased risk of coronary heart disease in women. When vegetable sources of fat and protein are chosen, these diets may moderately reduce the risk of coronary heart disease." [21]

Meta-studies conducted by scientists in 1997[22] and 2003[23] found high corelation between excessive amounts of saturated fats and coronary heart disease. Mayo Clinic highlighted oils that are high in saturated fats include coconut, palm oil and palm kernel oil. Those of lower amounts of saturated fats, and higher levels of unsaturated (preferably monounsaturated) fats like olive oil, peanut oil, canola oil, avocados, safflower, corn, sunflower, soy and cottonseed oils are generally healthier.[24] The National Heart, Lung and Blood Institute,[25] and other health authorities like World Heart Federation[26] have urged saturated fats be replaced with polyunsaturated and monounsaturated fats. The health body list olive and canola oils as sources of monosaturated oils while soybean and sunflower oils are rich with polyunsaturated fat. A 2005 research in Costa Rica suggests consumption of non-hydrogenated unsaturated oils like soybean and sunflower over palm oil.[27]

The Cochrane Collaboration published a meta-analyses of fat modification trials finding no significant effect on total mortality, but with significant reductions in the rate of cardiovascular events that was statistically significant in the high risk group.[28]

[edit] Fatty acid specificity

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.[29]

In 2005, Dutch scientists at Department of Human Biology, Maastricht University compared the effects of stearic acid with oleic and linoleic acids. Forty five subjects (27 women and 18 men) consumed, in random order, three experimental diets, each for five weeks. The results suggest stearic acid is not highly thrombogenic compared with oleic and linoleic acids.[30]

[edit] Cancer

[edit] Breast cancer

Main article: Epidemiology and etiology of breast cancer#MUFAs on erythrocyte membrane and derived discussion about dietary fatty acids

There is one theorized association between saturated fatty acids intake and increased breast cancer risk.

[edit] Prostate cancer

Main article: Prostate cancer#Oils and fatty acids

Myristic and palmitic saturated fatty acids are associated with prostate cancer.

[edit] Small intestine cancer

A prospective study of data from the NIH-AARP Diet and Health Study correlated saturated fat intake with cancer of the small intestine.[31]

[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..." [32] 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.[33][34] 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.[35][36][37]

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.[38][39]

Dr German and Dr Dillard of University of California and Nestle Research Center in Switzerland, in their 2004 review, pointed out that "no lower safe limit of specific saturated fatty acid intakes has been identified". No randomized clinical trials of low-fat diets or low-saturated fat diets of sufficient duration have been carried out. The influence of varying saturated fatty acid intakes against a background of different individual lifestyles and genetic backgrounds should be the focus in future studies.[40]

[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

One confounding issue in studies may be the formation of exogenous (outside the body) advanced glycation endproducts (AGEs) and oxidation products generated during cooking, which it appears some of the studies have not controlled for. It has been suggested that, "given the prominence of this type of food in the human diet, the deleterious effects of high-(saturated)fat foods may be in part due to the high content in glycotoxins, above and beyond those due to oxidized fatty acid derivatives." The glycotoxins, as he called them, are more commonly called AGEs[41]

  • A 3-year study conducted of 235 postmenopausal women with established coronary artery disease, many also having metabolic syndrome concluded that "in postmenopausal women with relatively low total fat intake, a greater saturated fat intake is associated with less progression of coronary atherosclerosis." Nevertheless, the authors deemed that "the findings do not establish causality." [42][43]
  • A study of 297 Portuguese males with acute myocardial infarction (MI), found that "total fat intake, lauric acid, palmitic acid [two common saturated fats] and oleic acid [a monoinsaturated fat] were inversely associated with acute MI" and concluded that "low intake of total fat and lauric acid from dairy products was related to acute MI". The authors suggest that "recommendations on fatty acid intake should aim for both an upper and lower limit"[44].
  • 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.[45]
  • 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 bias. The authors take the example of the "Finnish mental hospital study" in which saturated fat intakes were monitored more closely than were total fat intakes, therefore ignoring the possibility that simply a larger fat intake may lead to a higher risk of coronary diseases. It also suggests that other parameters were overlooked, such as carbohydrates intakes.[46]

[edit] Molecular description

Two-dimensional representation 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. ^ Ma, J; Folsom, Ar; Shahar, E; Eckfeldt, Jh (Sep 1995). "Plasma fatty acid composition as an indicator of habitual dietary fat intake in middle-aged adults. The Atherosclerosis Risk in Communities (ARIC) Study Investigators". The American journal of clinical nutrition 62 (3): 564–71. ISSN 0002-9165. PMID 7661118.  edit
  3. ^ U.S. Department of Agriculture, Agricultural Research Service. 2007. USDA National Nutrient Database for Standard Reference, Release 20. Nutrient Data Laboratory Home Page
  4. ^ a b c .nutritiondata.com --> Egg, yolk, raw, fresh Retrieved on August 24, 2009
  5. ^ Feinberg School > Nutrition > Nutrition Fact Sheet: Lipids Northwestern University. Retrieved on August 24, 2009
  6. ^ Grootveld, MARTIN; Silwood; Addis; Claxson; Serra; Viana (2001). "HEALTH EFFECTS OF OXIDIZED HEATED OILS1". Foodservice Research International 13: 41. doi:10.1111/j.1745-4506.2001.tb00028.x. 
  7. ^ 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
  8. ^ 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
  9. ^ Rivellese AA, Maffettone A, Vessby B, et al. (March 2003). "Effects of dietary saturated, monounsaturated and n-3 fatty acids on fasting lipoproteins, LDL size and post-prandial lipid metabolism in healthy subjects". Atherosclerosis 167 (1): 149–58. doi:10.1016/S0021-9150(02)00424-0. PMID 12618280. http://linkinghub.elsevier.com/retrieve/pii/S0021915002004240. 
  10. ^ Hu FB, Stampfer MJ, Manson JE, et al. (November 1997). "Dietary fat intake and the risk of coronary heart disease in women". N. Engl. J. Med. 337 (21): 1491–9. doi:10.1056/NEJM199711203372102. PMID 9366580. http://content.nejm.org/cgi/content/abstract/337/21/1491. 
  11. ^ Kromhout D, Menotti A, Bloemberg B, et al. (May 1995). "Dietary saturated and trans fatty acids and cholesterol and 25-year mortality from coronary heart disease: the Seven Countries Study". Prev Med 24 (3): 308–15. PMID 7644455. http://linkinghub.elsevier.com/retrieve/pii/S0091743585710493. 
  12. ^ Hu FB, Stampfer MJ, Manson JE, et al. (December 1999). "Dietary saturated fats and their food sources in relation to the risk of coronary heart disease in women". Am. J. Clin. Nutr. 70 (6): 1001–8. PMID 10584044. http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=10584044. 
  13. ^ Coronary heart disease in seven countries
  14. ^ Beegom R, Singh RB (January 1997). "Association of higher saturated fat intake with higher risk of hypertension in an urban population of Trivandrum in south India". Int. J. Cardiol. 58 (1): 63–70. doi:10.1016/S0167-5273(96)02842-2. PMID 9021429. http://linkinghub.elsevier.com/retrieve/pii/S0167-5273(96)02842-2. 
  15. ^ Lapinleimu H, Viikari J, Jokinen E, et al. (February 1995). "Prospective randomised trial in 1062 infants of diet low in saturated fat and cholesterol". Lancet 345 (8948): 471–6. doi:10.1016/S0140-6736(95)90580-4. PMID 7861873. 
  16. ^ 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
  17. ^ Mendis S, Samarajeewa U, Thattil RO (May 2001). "Coconut fat and serum lipoproteins: effects of partial replacement with unsaturated fats". Br. J. Nutr. 85 (5): 583–9. doi:10.1079/BJN2001331. PMID 11348573. http://journals.cambridge.org/abstract_S0007114501000836. 
  18. ^ Abbey M, Noakes M, Belling GB, Nestel PJ (May 1994). "Partial replacement of saturated fatty acids with almonds or walnuts lowers total plasma cholesterol and low-density-lipoprotein cholesterol". Am. J. Clin. Nutr. 59 (5): 995–9. PMID 8172107. http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=8172107. 
  19. ^ de Lorgeril M, Salen P, Martin JL, Monjaud I, Delaye J, Mamelle N (February 1999). "Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: final report of the Lyon Diet Heart Study". Circulation 99 (6): 779–85. PMID 9989963. http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=9989963. 
  20. ^ http://www.aims.ubc.ca/home/modules/conference/2005/med_diet_study_1994.pdf
  21. ^ Halton TL, Willett WC, Liu S, et al. (November 2006). "Low-carbohydrate-diet score and the risk of coronary heart disease in women". N. Engl. J. Med. 355 (19): 1991–2002. doi:10.1056/NEJMoa055317. PMID 17093250. http://content.nejm.org/cgi/content/short/355/19/1991. 
  22. ^ Clarke, R; Frost; Collins; Appleby; Peto (1997). "Dietary lipids and blood cholesterol: quantitative meta-analysis of metabolic ward studies". BMJ (Clinical research ed.) 314 (7074): 112–7. PMID 9006469. 
  23. ^ Mensink, RP; Zock; Kester; Katan (2003). "Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials". The American journal of clinical nutrition 77 (5): 1146–55. PMID 12716665. 
  24. ^ Dietary fats: Know which types to choose Mayo Clinic website
  25. ^ Choose foods low in saturated fat National Heart, Lung, and Blood Institute (NHLBI), NIH Publication No. 97-4064. 1997.
  26. ^ Diet & cardiovascular desease World Heart Federation website
  27. ^ Kabagambe, Baylin, Ascherio & Campos (November 2005). "The Type of Oil Used for Cooking Is Associated with the Risk of Nonfatal Acute Myocardial Infarction in Costa Rica". Journal of Nutrition. pp. 2674–2679. http://jn.nutrition.org/cgi/content/abstract/135/11/2674. 
  28. ^ [Reduced or modified dietary fat for preventing cardiovascular disease http://mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD002137/frame.html]
  29. ^ World Health Organization Disease-specific recommendations
  30. ^ Thijssen, Myriam A.M.A.; Hornstra, Gerard; Mensink, Ronald P. (2005). "Stearic, Oleic, and Linoleic Acids Have Comparable Effects on Markers of Thrombotic Tendency in Healthy Human Subjects". Journal of Nutrition 135 (12): 2805. PMID 16317124. http://jn.nutrition.org/cgi/content/abstract/135/12/2805. 
  31. ^ Cross, A.; Leitzmann, M.; Subar, A.; Thompson, F.; Hollenbeck, A.; Schatzkin, A. (2008). "A prospective study of meat and fat intake in relation to small intestinal cancer". Cancer research 68 (22): 9274–9279. doi:10.1158/0008-5472.CAN-08-2015. PMID 19010900.  edit
  32. ^ Trends in Intake of Energy, Protein, Carbohydrate, Fat, and Saturated Fat — United States, 1971–2000
  33. ^ Lichtenstein AH, Appel LJ, Brands M, et al. (July 2006). "Diet and lifestyle recommendations revision 2006: a scientific statement from the American Heart Association Nutrition Committee". Circulation 114 (1): 82–96. doi:10.1161/CIRCULATIONAHA.106.176158. PMID 16785338. http://circ.ahajournals.org/cgi/content/full/114/1/82. 
  34. ^ Smith SC, Jackson R, Pearson TA, et al.' (June 2004). "Principles for national and regional guidelines on cardiovascular disease prevention: a scientific statement from the World Heart and Stroke Forum" (PDF). Circulation 109 (25): 3112–21. doi:10.1161/01.CIR.0000133427.35111.67. PMID 15226228. http://circ.ahajournals.org/cgi/reprint/109/25/3112.pdf. 
  35. ^ World Health Organization Diet, Nutrition and the Prevention of Chronic Diseases
  36. ^ U.S. Department of Health and Human Services U.S. Department of Agriculture Dietary Guidelines for Americans 2005
  37. ^ U.S. Department of Health and Human Services Dietary Guidelines for Americans 2005
  38. ^ World Health Organization Risk factor: lipids
  39. ^ World Health Organization Prevention: personal choices and actions
  40. ^ Saturated fats: what dietary intake? J Bruce German and Cora J Dillard, Am J Clin Nutr, 2004; 80:550–9
  41. ^ Koschinsky T, He CJ, Mitsuhashi T, et al. (June 1997). "Orally absorbed reactive glycation products (glycotoxins): an environmental risk factor in diabetic nephropathy". Proc. Natl. Acad. Sci. U.S.A. 94 (12): 6474–9. doi:10.1073/pnas.94.12.6474. PMID 9177242. PMC 21074. http://www.pnas.org/cgi/pmidlookup?view=long&pmid=9177242. 
  42. ^ 'Surprising' data: saturated fat may slow atherosclerotic progression in postmenopausal women, OB/GYN News, July 2004
  43. ^ Mozaffarian D, Rimm EB, Herrington DM (November 2004). "Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women". Am. J. Clin. Nutr. 80 (5): 1175–84. PMID 15531663. PMC 1270002. http://www.ajcn.org/cgi/content/full/80/5/1175. 
  44. ^ Lopes, Carla; Aro, Antti; Azevedo, Ana; Ramos, Elisabete; Barros, Henrique (2007). "Intake and adipose tissue composition of fatty acids and risk of myocardial infarction in a male portuguese community sample". Journal of the American Dietetic Association (New-York: Elsevier) 107 (2): 276-286. http://cat.inist.fr/?aModele=afficheN&cpsidt=18487382. 
  45. ^ 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 (6pages=730–6). PMID 11722953. 
  46. ^ Saturated fat prevents coronary artery disease? An American paradox
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