Saturated fat

Saturated fat is fat that consists of triglycerides containing only saturated fatty acids.

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 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 and chocolate, and some prepared foods [ [http://www.dietaryfiberfood.com/fat-saturated.php Saturated fat food sources] ] .

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.

Examples of saturated fatty acids

Some common examples of fatty acids are:
*lauric acid with 12 carbon atoms (contained in coconut oil, palm oil and breast milk,
*myristic acid with 14 carbon atoms (contained in cow milk and dairy products),
*palmitic acid with 16 carbon atoms (contained in palm oil, hence the name, and meat),
*stearic acid with 18 carbon atoms (also contained in meat and cocoa butter).

Health issues

Harvard Nurses' Health Study found that diets lower in carbohydrate and higher in protein and animal fat are associated with a statistically insignificant decrease in 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." [cite journal |author=Halton TL, Willett WC, Liu S, "et al" |title=Low-carbohydrate-diet score and the risk of coronary heart disease in women |journal=N. Engl. J. Med. |volume=355 |issue=19 |pages=1991–2002 |year=2006 |month=Nov |pmid=17093250 |doi=10.1056/NEJMoa055317 |url=http://content.nejm.org/cgi/content/short/355/19/1991 ]

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 [MS Wolfe, JK Sawyer, TM Morgan, BC Bullock and LL Rudel [http://atvb.ahajournals.org/cgi/content/abstract/14/4/587 Dietary polyunsaturated fat decreases coronary artery atherosclerosis in a pediatric-aged population of African green monkeys] "Arteriosclerosis and Thrombosis" Vol 14, 587–597] and human, such as a study of infant diets cite journal |author=Lapinleimu H, Viikari J, Jokinen E, "et al" |title=Prospective randomised trial in 1062 infants of diet low in saturated fat and cholesterol |journal=Lancet |volume=345 |issue=8948 |pages=471–6 |year=1995 |month=Feb |pmid=7861873 |doi= |url=] , 22 hypercholesterolemic men [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 [http://www.annals.org/cgi/content/full/134/12/1115 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] [cite journal |author=Rivellese AA, Maffettone A, Vessby B, "et al" |title=Effects of dietary saturated, monounsaturated and n-3 fatty acids on fasting lipoproteins, LDL size and post-prandial lipid metabolism in healthy subjects |journal=Atherosclerosis |volume=167 |issue=1 |pages=149–58 |year=2003 |month=Mar |pmid=12618280 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0021915002004240] [cite journal |author=Hu FB, Stampfer MJ, Manson JE, "et al" |title=Dietary fat intake and the risk of coronary heart disease in women |journal=N. Engl. J. Med. |volume=337 |issue=21 |pages=1491–9 |year=1997 |month=Nov |pmid=9366580 |doi= |url=http://content.nejm.org/cgi/content/abstract/337/21/1491] 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. [cite journal |author=Kromhout D, Menotti A, Bloemberg B, "et al" |title=Dietary saturated and trans fatty acids and cholesterol and 25-year mortality from coronary heart disease: the Seven Countries Study |journal=Prev Med |volume=24 |issue=3 |pages=308–15 |year=1995 |month=May |pmid=7644455 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0091743585710493] [cite journal |author=Hu FB, Stampfer MJ, Manson JE, "et al" |title=Dietary saturated fats and their food sources in relation to the risk of coronary heart disease in women |journal=Am. J. Clin. Nutr. |volume=70 |issue=6 |pages=1001–8 |year=1999 |month=Dec |pmid=10584044 |doi= |url=http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=10584044] [ [http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TB0-3RJPSRP-S&_user=38557&_coverDate=03%2F31%2F1997&_rdoc=1&_fmt=full&_orig=search&_cdi=5128&_sort=d&_docanchor=&view=c&_acct=C000004358&_version=1&_urlVersion=0&_userid=38557&md5=c659c1e0202b8126829ef23a2e1b2417 Coronary heart disease in seven countries] ] [cite journal |author=Beegom R, Singh RB |title=Association of higher saturated fat intake with higher risk of hypertension in an urban population of Trivandrum in south India |journal=Int. J. Cardiol. |volume=58 |issue=1 |pages=63–70 |year=1997 |month=Jan |pmid=9021429 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0167-5273(96)02842-2] Additionally, controlled experimental studies have found that people consuming high saturated fat diets experience negative cholesterol profile changes. [ Hanne Müller, Anja S. Lindman, Anne Lise Brantsæter, and Jan I. Pedersen [http://jn.nutrition.org/cgi/content/abstract/133/1/78 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] [cite journal |author=Mendis S, Samarajeewa U, Thattil RO |title=Coconut fat and serum lipoproteins: effects of partial replacement with unsaturated fats |journal=Br. J. Nutr. |volume=85 |issue=5 |pages=583–9 |year=2001 |month=May |pmid=11348573 |doi= |url=http://journals.cambridge.org/abstract_S0007114501000836] [cite journal |author=Abbey M, Noakes M, Belling GB, Nestel PJ |title=Partial replacement of saturated fatty acids with almonds or walnuts lowers total plasma cholesterol and low-density-lipoprotein cholesterol |journal=Am. J. Clin. Nutr. |volume=59 |issue=5 |pages=995–9 |year=1994 |month=May |pmid=8172107 |doi= |url=http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=8172107] 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.U.S. Department of Health and Human Services U.S. Department of Agriculture [http://www.fda.gov/ohrms/dockets/dockets/06q0458/06q-0458-sup0001-02.pdf Dietary Guidelines for Americans 2005] ]

Experiments in which subjects were randomly assigned to either a control or Mediterranean diet (which replaces saturated fat with mono and polyunsaturated fat) 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. [cite journal |author=de Lorgeril M, Salen P, Martin JL, Monjaud I, Delaye J, Mamelle N |title=Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: final report of the Lyon Diet Heart Study |journal=Circulation |volume=99 |issue=6 |pages=779–85 |year=1999 |month=Feb |pmid=9989963 |doi= |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=9989963] [http://www.aims.ubc.ca/home/modules/conference/2005/med_diet_study_1994.pdf]

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. [World Health Organization [http://www.who.int/nutrition/topics/5_population_nutrient/en/index12.html Disease-specific recommendations] ]

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. [cite journal |author=Valeria Pala, Vittorio Krogh, Paola Muti, Véronique Chajès, Elio Riboli, Andrea Micheli, Mitra Saadatian, Sabina Sieri, Franco Berrino |title=Erythrocyte Membrane Fatty Acids and Subsequent Breast Cancer: a Prospective Italian Study |journal=JNCL |volume=93 |year=2001 |url=http://jnci.oxfordjournals.org/cgi/content/full/93/14/1088 |accessdate=2008-03-22 |pmid=11459870]

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..." [ [http://www.cdc.gov/od/oc/media/mmwrnews/n040206.htm#mmwr2 Trends in Intake of Energy, Protein, Carbohydrate, Fat, and Saturated Fat — United States, 1971–2000] ] 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. [cite journal |author=Lichtenstein AH, Appel LJ, Brands M, "et al" |title=Diet and lifestyle recommendations revision 2006: a scientific statement from the American Heart Association Nutrition Committee |journal=Circulation |volume=114 |issue=1 |pages=82–96 |year=2006 |month=Jul |pmid=16785338 |doi=10.1161/CIRCULATIONAHA.106.176158 |url=http://circ.ahajournals.org/cgi/content/full/114/1/82] [cite journal |author=Smith SC, Jackson R, Pearson TA, "et al" |title=Principles for national and regional guidelines on cardiovascular disease prevention: a scientific statement from the World Heart and Stroke Forum |journal=Circulation |volume=109 |issue=25 |pages=3112–21 |year=2004 |month=Jun |pmid=15226228 |doi=10.1161/01.CIR.0000133427.35111.67 |url=http://circ.ahajournals.org/cgi/reprint/109/25/3112.pdf] 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. [World Health Organization [http://whqlibdoc.who.int/trs/WHO_TRS_916.pdf Diet, Nutrition and the Prevention of Chronic Diseases] ] [U.S. Department of Health and Human Services [http://www.fda.gov/ohrms/dockets/dockets/06q0458/06q-0458-sup0001-02.pdf Dietary Guidelines for Americans 2005] ]

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. [World Health Organization [http://www.who.int/cardiovascular_diseases/en/cvd_atlas_06_lipids.pdf Risk factor: lipids] ] [World Health Organization [http://www.who.int/cardiovascular_diseases/en/cvd_atlas_20_personal_choices.pdf Prevention: personal choices and actions] ]

Another confounding issue 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." [34] The glycotoxins, as he called them, are more commonly called AGEs [cite journal |author=Koschinsky T, He CJ, Mitsuhashi T, "et al" |title=Orally absorbed reactive glycation products (glycotoxins): an environmental risk factor in diabetic nephropathy |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=94 |issue=12 |pages=6474–9 |year=1997 |month=Jun |pmid=9177242 |pmc=21074 |doi= |url=http://www.pnas.org/cgi/pmidlookup?view=long&pmid=9177242]

Contrary research

* 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". [ [http://findarticles.com/p/articles/mi_m0CYD/is_13_39/ai_n6114090 'Surprising' data: saturated fat may slow atherosclerotic progression in postmenopausal women] , OB/GYN News, July 2004] [cite journal |author=Mozaffarian D, Rimm EB, Herrington DM |title=Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women |journal=Am. J. Clin. Nutr. |volume=80 |issue=5 |pages=1175–84 |year=2004 |month=Nov |pmid=15531663 |pmc=1270002 |doi= |url=http://www.ajcn.org/cgi/content/full/80/5/1175] [cite journal |author=Knopp RH, Retzlaff BM |title=Saturated fat prevents coronary artery disease? An American paradox |journal=Am. J. Clin. Nutr. |volume=80 |issue=5 |pages=1102–3 |year=2004 |month=Nov |pmid=15531654 |doi= |url=http://www.ajcn.org/cgi/content/full/80/5/1102]

* A study of 297 acute MI cases in Portuguese males, published in February 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". [ [http://findarticles.com/p/articles/mi_m0887/is_3_26/ai_n18791442 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)]

* 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.cite journal |author=Glew RH, Williams M, Conn CA, "et al" |title=Cardiovascular disease risk factors and diet of Fulani pastoralists of northern Nigeria |journal=Am. J. Clin. Nutr. |volume=74 |issue=6 |pages=730–6 |year=2001 |pmid=11722953 |doi=]

* 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. [ [http://www.ajcn.org/cgi/content/full/80/5/1102 Saturated fat prevents coronary artery disease? An American paradox] ]

Molecular description

ee also

*Trans fat
*Unsaturated fat
*Advanced glycation endproduct
*List of vegetable oils
*Diet and heart disease
*Iodine number
*Food groups
*Food guide pyramid
*Junk food
*Fast food
*Healthy diet

References