An Unjustified Knock Against Grass Fed Beef

December 2nd, 2010

Animals raised in a natural environment and on their natural diet are likely be healthier, and in turn, be a source of higher quality meat. Based on this premise, choosing meat from pasture raised animals makes a lot of sense and is supported by research that has identified a number of ways in which this type of meat is superior. However, a recent study done by researchers from Texas A&M is being used to claim the opposite, that beef from grain fed cattle is healthier than beef from pasture fed cattle.

Although there are many great reasons to choose meat from pasture raised livestock, eating conventionally produced meat is not necessarily a guarantee for poor health. Someone who primarily eats whole foods, is active, and manages stress well will still be likely to enjoy good health despite the concerns associated with conventionally produced meat. However, to insinuate in a general sense that beef from grain fed cattle is healthier than that from pasture fed beef is quite a stretch in my opinion.

Does HDL Cholesterol Define Overall Health?

Unfortunately, the full text of the Texas A&M study hasn’t been published, but the abstract1 provides enough of an overview to understand the basis of the research. 27 men each consumed 3 types of ground beef with each type being consumed exclusively for a 5 week period. The men were split into 3 groups to alter the order of the 5 week periods. One type of ground beef was from pasture fed cattle while the other two were from cattle fed corn for either a short or long duration.

The researchers found a statistically significant correlation between the amount of monounsaturated fat in the ground beef and the participants’ plasma levels of high density lipoproteins (HDL). This is considered to be beneficial because higher levels of HDL, which is often referred to as “good cholesterol,” have been associated with a reduced risk for heart disease. The beef from the cattle fed corn for the longest duration contained the most monounsaturated fat while the beef from the pasture raised cattle contained the least. From this, the researchers concluded that “consumption of high-oleic acid ground beef can increase HDL-C.”1 Fair enough.

Although this conclusion is specific and reasonable, at least based on the information provided by the abstract, the authors made a major and inappropriate projection by stating in the study’s title that “ground beef from corn-fed cattle provides greater health benefits than ground beef from pasture-fed cattle.” The vagueness of “greater health benefits” can easily be misconstrued to mean that beef from grain fed cattle is healthier in general than beef from pasture fed cattle. If you search for articles based on this research, you can see that this is exactly what happened. In fact, there’s even an article about the study on the Texas A&M website titled “Study shows ground beef from grain-fed cattle healthier than grass-fed.”2

HDL is only one of many factors associated with heart disease, and it’s not even one of the more important ones.96 Furthermore, although heart disease is the leading cause of death in the United States,3 it’s only one of many conditions that result in poor health and compromised quality of life. As such, I consider it inappropriate to use improved HDL levels as the justification for implying that beef from grain fed cattle is better for overall health. Besides, the Texas A&M researchers failed to acknowledge a number of other differences between the two types of meat that are arguably much more important.

Balance of Essential Fatty Acids

It’s estimated that the relative intakes of the omega-3 and omega-6 essential fatty acids throughout human evolution were roughly equivalent. However, due to changes in agricultural methods and an increase in the use of vegetable oils, we now consume as much as 20 times more omega-6 fatty acids than omega-3 fatty acids. Essential fatty acids have many important physiological roles, and because the human body cannot produce them, we must obtain them through diet. However, the imbalanced intake that is now common has been shown to be a significant concern due to its association with heart disease, cancer, asthma, arthritis, and mental illness.4-10

Research has shown that meat from pasture raised animals tends to have a much more favorable ratio of omega-6 to omega-3 fatty acids than meat from grain fed animals.11-14 In one case, the ratio in meat from grain fed animals was shown to be nearly 5 times greater.14 In this regard, meat from grain fed animals presents more of a risk for heart disease and other serious health concerns.

Vulnerability to Lipid Oxidation

Polyunsaturated fatty acids, including the omega-6 and omega-3 essential fatty acids, are very susceptible to oxidation.15-17 The oxidation of these fatty acids produces free radicals that are damaging to cells and are associated with a number of health concerns including heart disease, stroke, cancer, arthritis, asthma, and accelerated aging.18-23 They’re believed to cause damage to the endothelial cells that line arteries and induce the lesions associated with atherosclerosis.24,25 Low density lipprotens (LDL), which are often given the misleading designation of “bad cholesterol,” contain these easily oxidized polyunsaturated fatty acids. When they’re oxidized, the LDL molecules that contain them are referred to as “oxidized LDL.” Although it’s somewhat questionable to refer to LDL in general as “bad cholesterol,” oxidized LDL in particular is believed to be a significant cause of artery damage and increase the risk of atherosclerosis.26-30

Unfortunately, the polyunsaturated fat in food can become oxidized when exposed to oxygen, light, or the high temperatures of cooking,15-17,22,23,31 and the consumption of this oxidized fat has been shown to increase the concentration of oxidized LDL in the blood.32,33 The fat in meat from grain fed animals has been shown to be more susceptible to oxidation than the fat in meat from pasture fed animals.13,34 This is believed to be a result of meat from grain fed animals containing less vitamin E13,34 which is known to protect against the oxidation of fatty acids.17,22,35,36 Based on this, meat from grain fed livestock poses a greater risk of increasing oxidized LDL levels, and in turn, increasing the risk of atherosclerosis.

Even if polyunsaturated fatty acids are not oxidized when consumed, an excessive intake increases the polyunsaturated content of LDL molecules which makes the LDL more susceptible to oxidation.37-39 Although the meat from grain fed animals tends to contain an unfavorable ratio of omega-6 to omega-3 fatty acids, it doesn’t necessarily contain more polyunsaturated fatty acids in general. However, this less desirable ratio could encourage one to consume more omega-3 fatty acids, and in turn, consume more polyunsaturated fatty acids overall.

In regard to the results of the Texas A&M study, one of the benefits of HDL is that it protects against LDL oxidation.26,29,40,41 However, the improved HDL levels observed by the researchers are negated and of little value if the meat that promotes this improvement also increases the risk of LDL oxidation and its harmful effects.

Hormones, Antibiotics, and Pesticides

Despite being fed an unnatural diet, some grain fed livestock are raised with great care and may only be fed such a diet for a brief period. However, it’s more likely for the meat commonly found in grocery stores to be of poorer quality and come from animals raised under the questionable conditions of factory farms. These animals may be given hormones to accelerate or increase their growth, and they may be exposed to pesticide residues and mold toxins from being fed low quality feed. Because such conditions are likely to impair their health, they may also be given antibiotics on a regular basis to reduce the incidence of illness.

This is a moral dilemma to say the least, but the focus of this discussion is nutritional quality. Research has shown that the residues of pesticides, hormones, and antibiotics that conventionally raised livestock are commonly exposed to can be found in their meat.42,97-99 This presents a number of health concerns and is obviously not synonymous with a high level of quality.

Misrepresentation of Trans Fat

There’s little doubt that trans fat is unhealthy and increases the risk for heart disease. However, this is a generalization that applies to the trans fat that’s artificially derived from vegetable oils. During this process, which is referred to as hydrogenation, hydrogen atoms are added to unsaturated fatty acids to give them the more solid and stable properties of saturated fatty acids.43

Although the harmful nature of the trans fat found in hydrogenated vegetable oils has become common knowledge, not as many people realize that there are natural forms of trans fat that exist in the meat and milk of ruminant animals.44 However, it’s important to realize that these trans fats differ in structure than those derived from vegetable oils. Elaidic acid is the primary trans fat found in hydrogenated vegetable oils while trans-vaccenic acid is the primary trans fat found in ruminant animals. Although these two fatty acids are isomers of each other, which means that they share the same chemical formula, they have different structures based on a double bond being located in different positions.45 Although this might sound trivial, it’s not uncommon for such a seemingly small difference in molecular structure to have a significant impact.

Although both of these fatty acids are technically trans fatty acids, only one of them is deserving of the negative connotation associated with trans fat. Research has shown that it’s the elaidic acid in hydrogenated vegetable oils that’s associated with an increased risk of heart disease, not the trans-vaccenic acid naturally found in the meat and milk of ruminant animals.45-47 In addition, the meat and milk of ruminants also contain another type of trans fat called conjugated linoleic acid (CLA) which is believed to have many health benefits including the potential to reduce body fat, increase lean body mass, protect against cancer, heart disease, and diabetes, and enhance immune function and bone development.11,48-51 Trans-vaccenic acid, the dominant trans fatty acid in animal fat, is believed to be a precursor to CLA in both animals and humans, and consumption of trans-vaccenic acid has been shown to increase levels of CLA.52

Beef from pasture fed animals tends to contain more trans-vaccenic acid and CLA than animals fed grain.12,53 Based on the potential benefits of CLA and the evidence of trans-vaccenic acid not being harmful, this can be regarded as a benefit. However, one of the Texas A&M researchers seems to have put a negative and misleading spin on the issue as if there’s no difference between these natural trans fatty acids and the trans fat artificially derived from vegetable oils. On the university’s own website, he’s quoted as saying that “as we talked to some user groups and told them that we had found pasture-fed beef is higher in saturated [and] trans-fat, they were shocked.”2 (I added [and] to the quote assuming a transcription mistake based on the fact that there’s no such thing as a “saturated trans fat.” The existence of such a fat is contradictory by definition and isn’t even possible.)

Good Science or Just Clever Language?

Most people are probably not aware of the differences between trans fat from ruminant animals and hydrogenated vegetable oils, and if not, they’re certainly not aware of the different health implications. Based on this, they’re likely to assume that all trans fats are bad and interpret “shocked” as a negative response. I truly hope that this statement about trans fat wasn’t made with malicious intent, but either way, the potential for it to be misleading is still the same.

Along with the projection of improved HDL levels defining overall health, this is an unfortunate example of how subtle language choices made by researchers can encourage information to be misconstrued by the media. Good science relies on seeking truth and presenting it clearly to minimize the potential for misinterpretation. Unfortunately, it seems to me that this research is lacking these qualities.

A Side Note About Saturated Fat

Although I don’t consider the difference in saturated fat content to be an important comparison between the meat from pasture fed and grain fed animals, I feel obligated to acknowledge it since it’s mentioned in the quote about trans fat that I referenced.

Some research confirms that beef from pasture fed cattle contains more saturated fat,14 but other research has shown it to contain less.53 Either way, this is only relevant if you believe that saturated fat is inherently unhealthy. Despite the popularity of the belief that it’s harmful and is a significant risk factor for heart disease, there is quite a bit of convincing support indicating that saturated fat is misunderstood.54-66,96 In fact, it’s essential for important aspects of health. Saturated fat is a component of adipose tissue,67-69 and as such, contributes to energy storage and thermal insulation.70 Its concentration has been found to be higher in visceral fat which indicates its importance in protecting and supporting vital organs.69 It’s also essential for proper function of cell membranes,71-73 the brain and nervous system,74,75 and even the lungs.76-78 In addition, saturated fat contributes to the resiliency of skin,79,84-87 can enhance immunity,79-83 and has ironically been shown to be a significant if not dominant source of energy for the heart.88-92

Saturated fat also relates to the previous discussion about oxidized LDL. Research has shown the blood concentration of oxidized LDL to increase after after consuming a supposedly healthy diet that decreases saturated fat and overall fat intake while increasing polyunsaturated fat intake.93

A Different Outlook on What’s “Healthy”

Improved HDL levels are generally a byproduct of living a truly healthy lifestyle with the intent of promoting optimal health. For example, exercising is an important part of maintaining and promoting good health, and it has also been shown to improve HDL levels.94,95

One of the Texas A&M researchers claimed that “we looked at the scientific literature and could not find any justifications for the statement that pasture-fed beef is better for you.”2 I won’t make any assumptions about why they didn’t find any of the research that I referenced in this article, but the point remains that it exists, isn’t difficult to find, and in my opinion provides plenty of justification.

Because of the multitude of factors that can influence health, making healthy decisions requires a broad perspective. The Texas A&M researchers found that ground beef from grain fed cattle improves HDL levels, and from this very narrow and focused perspective concluded that meat from grain fed cattle is healthier than meat from pasture fed cattle. However, with a broader perspective that considers essential fatty acid imbalance, susceptibility to oxidation, and the existence of chemical residues, it seems to me that it’s their statement that isn’t justified.

If anything, the Texas A&M study supports the benefit of consuming monounsaturated fatty acids. However, if you want to increase your intake of this type of fat, you’d be better off eating avocados than eating meat from an animal not fed its natural diet.

[1. Gilmore LA, Walzem RL, Crouse SF, Smith SB. "Ground beef from corn-fed cattle provides greater health benefits than ground beef from pasture-fed cattle." The FASEB Journal.]
[2. Fannin B. "Study shows ground beef from grain-fed cattle healthier than grass-fed." AgriLife NEWS. 2010. Accessed 2010-11-03.]
[3. Lloyd-Jones D, Adams R, Carnethon M, De Simone G, Ferguson B, Flegal K, Ford E, Furie K, Go A, Greenlund K, Haase N, Hailpern S, Ho M, Howard V, Kissela B, Kittner S, Lackland D, Lisabeth L, Marelli A, McDermott M, Meigs J, Mozaffarian D, Nichol Graham, O'Donnell C, Roger V, Rosamond W, Sacco R, Sorlie P, Stafford R, Steinberger J, Thom T, Wasserthiel-Smoller S, Wong N, Wylie-Rosett J, Hong Y. "Heart Disease and Stroke Statistics - 2009 Update." Circulation. 2009. 119:e21-e181.]
[4. Simopoulos AP. "The importance of the ratio of omega-6/omega-3 essential fatty acids." Biomedicine & Pharmacotherapy. 2002. 56:365-379.]
[5. Simopoulos AP. "Essential fatty acids in health and chronic disease." American Journal of Clinical Nutrition. 1999. 70(3):560S-569S.]
[6. Youdim KA, Martin A, Joseph JA. "Essential fatty acids and the brain: possible health implications." International Journal of Developmental Neuroscience. 2000. 18:383-399.]
[7. Ruxton CHS, Reed SC, Simpson MJA, Millington KJ. "The health benefits of omega-3 polyunsaturated fatty acids: a review of the evidence." Journal of Human Nutrition and Dietetics. 2004. 17:449-459.]
[8. Connor WE. "Importance of n-3 fatty acids in health and disease." American Journal of Clinical Nutrition. 2000. 71(1):171S-175S.]
[9. Holman RT. "The Slow Discovery of the Importance of w3 Essential Fatty Acids in Human Health." Journal of Nutrition. 1998. 128(2):427S-433S.]
[10. Simopoulos AP. "Omega-3 fatty acids in health and disease and growth and development." American Journal of Clinical Nutrition. 1991. 54:438-463.]
[11. Razminowicz RH, Kreuzer M, Scheeder MRL. "Quality of retail beef from two grass-based production systems in comparison with conventional beef. Meat Science. 2006. 73:351-361]
[12. Nuernberg K, Dannenberger D, Nuernberg G, Ender K, Voigt J, Scollan ND, Wood JD, Nute GR, Richardson RI. "Effect of a grass-based and concentrate feeding system on meat quality characteristics and fatty acid composition of longissimus muscle in different cattle breeds." Livestock Production Science. 2005. 94:137-147.]
[13. O'Sullivan A, O'Sullivan K, Galvin K, Maloney AP, Troy DJ, Kerry JP. "Grass silage versus maize silage effects on retail packaged beef quality." Journal of Animal Science. 2002. 80:1556-1563.]
[14. manner W, Maxwell RJ, Williams JE. "Effects of Dietary Regimen and Tissue Site on Bovine Fatty Acid Profiles." Journal of Animal Science. 1984. 59:109-121.]
[15. Fernandez J, Perez-Alvarez JA, Fernandez-Lopez JA. "Thiobarbituric acid text for monitoring lipid oxidation in meat." Food Chemistry. 1997. 59(3):345-353.]
[16. Labuza TP, Dugan Jr. LR. "Kinetics of lipid oxidation in foods." Critical Reviews in Food Science and Nutrition. 1971. 2(3):355-405.]
[17. Halliwell B, Chirico S. "Lipid peroxidation: its mechanism, measurement, and significance." The American Journal of Clinical Nutrition. 1993. 57:715S-725S.]
[18. Esterbauer H. "Cytotoxicity and genotoxicity of lipid-oxidation products." The American Journal of Clinical Nutrition. 1993. 57:779S-786S.]
[19. Addis PB. "Occurrence of Lipid Oxidation Products in Foods." Food and Chemical Toxicology. 1986. 24(10-11):1021-1030.]
[20. Beckman KB, Ames BN. "The Free Radical Theory of Aging Matures." Physiological Reviews. 1998. 78(2):547-581.]
[21. Droge W. "Free Radicals in the Physiological Control of Cell Function." Physiological Reviews. 2002. 82:47-95.]
[22. Frankel EN. "Lipid Oxidation: Mechanisms, Products and Biological Significance." Journal of the American Oil Chemists' Society. 1984. 61(12):1908-1917.]
[23. Frankel EN. "Chemistry of Free Radical and Singlet Oxidation of Lipids." Progress in Lipid Research. 1985. 23:197-221.]
[24. Stringer MD, Gorog PG, Freeman A, Kakkar VV. "Lipid peroxides and atherosclerosis." British Medical Journal. 1989. 298:281-284.]
[25. Hennig B, Chow CK. "Lipid Peroxidation and Endothelial Cell Injury: Implications in Atherosclerosis." Free Radical Biology & Medicine. 1988. 4:99-106.]
[26. Heery JH, Kozak M, Stafforini DM, Jones DA, Zimmerman GA, McIntyre TM, Prescott SM. "Oxidatively Modified LDL Contains Phospholipids With Platelet-activating Factor-like Activity and Stimulates the Growth of Smooth Muscle Cells." Journal of Clinical Investigation. 1995. 96:2322-2330.]
[27. Hovoet P, Stassen J, Cleemput JV, Collen D, Vanhaecke J. "Oxidized Low Density Lipoproteins in Patients With Transplant-Associated Coronary Artery Disease." Arteriosclerosis, Thrombosis, and Vascular Biology. 1998. 18:100-107.]
[28. Holvoet P, Vanhaecke J, Janssens S, Van de Werf F, Collen D. "oxidized LDL and Malondialdehyde-Modified LDL in Patients With Acute Coronary Syndromes and Stable Coronary Artery Disease." Circulation. 1998. 98:1487-1494.]
[29. Mertens A, Holvoet P. "Oxidized LDL and HDL: antagonists in atherothrombosis." The FASEB Journal. 2001. 15:2073-2084.]
[30. Steinberg D. "Low Density Lipoprotein Oxidation and Its Pathobiological Significance." The Journal of Biological Chemistry. 1997. 272:20963-20966.]
[31. Gray JI, Gomaa EA, Buckley DJ. "Oxidative Quality and Shelf Life of Meats." Meat Science. 1996. 43:111S-123S.]
[32. Straprans I, Rapp JH, Pan XM, Kim KY, Feingold KR. "Oxidized lipids in the diet are a source of oxidized lipid in chylomicrons of human serum." Arterioscleroisis, Thrombosis, and Vascular Biology. 1994. 14:1900-1905.]
[33. Straprans I, Rapp JH, Pan X,M Hardman DA, Feingold KR. "Oxidized Lipids in the Diet Accelerate the Development of Fatty Streaks in Cholesterol-Fed Rabbits." Arteriosclerosis, Thrombosis, and Vascular Biology. 1996. 16:533-538.]
[34. Warren HE, Scollan ND, Nute GR, Hughes SI, Wood JD, Richardson RI. "Effects of breed and a concentrate or grass silage diet on beef quality in cattle of 3 ages. II. meat stability and flavour." Meat Science. 2008. 78:270-278.]
[35. Desrumaux C, Deckert V, Athias A, Masson D, Lizard G, Palleau V, Gambert P, Lagrost L. "Plasma phospholipid transfer protein prevents vascular endothelium dysfunction by delivering a-tocopherol to endothelial cells." The FASEB Journal. 1999. 13:883-892.]
[36. Buettner BR. "The Pecking Order of Free Radicals and Antioxidants: Lipid Peroxidation, a-Tocopherol, and Ascorbate." Archives of Biochemistry and Biophysics. 1993. 300(2):535-543.]
[37. Reaven P. Parthasarathy S, Grasse BJ, Miller E, Almazan F, Mattson FH, Khoo JC, Steinberg D, Witztum JL. "Feasibility of using an oleate-rich diet to reduce the susceptibility of low-density lipoprotein to oxidative modification in humans." American Journal of Clinical Nutrition. 1991. 54:701-706.]
[38. Louheranta AM, Porkkala-Sarataho EK, Myyssonen MK, Salomen RM, Salomen JT. "Linoleic acid intake and susceptibility of very-low-density and low-density lipoproteins to oxidation in men." American Journal of Clinical Nutrition. 1996. 63:698-703.]
[39. Bonanome A, Pagnan A, Biffanti S, Opportuno A, Sorgato F, Dorella M, Maiorino M, Ursini F. "Effect of Dietary Monounsaturated and Polyunsaturated Fatty Acids on the Susceptibility of Plasma Low Density Lipoproteins to oxidative Modification." Arterisclerosis, Thrombosis, and Vascular Biology. 1992. 12:529-533.]
[40. Watson AD, Berliner JA, Hama SY, La Du BN, Faull KF, Fogelman AM, Navab M. "Protective Effect of High Density Lipoprotein Associated Paraoxonase. Inhibition of the Biological Activity of Minimally Oxidized Low Density Lipoprotein." Journal of Clinical Investigation. 1995. 96:2882-2891.]
[41. Aviram M, Rosenblat M, Bisagaier CL, Newton RS, Primo-Parmo SL, La Du BN. "Paraoxonase Inhibits High-density Lipoprotein Oxidation and Preserves its Functions. A Possible Peroxidative Role for Paraoxonase." Journal of Clinical Investigation. 1998. 8:1581-1590.]
[42. Coye MJ. "The Health Effects of Agricultural Production: II. The Health of the Community." Journal of Public Health Policy. 1986. 7(3):340-354.]
[43. Emken EA. "Nutrition and Biochemistry of Trans and Positional Fatty Acid Isomers in Hydrogenated Oils." Annual Review of Nutrition. 1984. 4:339-376.]
[44. Leth T, Ovesen L, Hansen K. "Fatty Acid Composition of Meat from Ruminants, with Special Emphasis on trans Fatty Acids." Journal of the American Oil Chemists' Society. 1998. 75:1001-1005.]
[45. Willett WC, Stampfer MJ. "Intake of trans fatty acids and risk of coronary heart disease among women." Lancet. 1993. 341(8845):581-585.]
[46. Hodgson JM, Wahlqvist ML, Boxall JA, Balazs ND. "Platelet trans fatty acids in relation to angiographically assessed coronary artery disease." Atherosclerosis. 1996. 120:147-154.]
[47. Jakobsen MU, Overvad K, Dyerberg J, Heitmann BL. "Intake of ruminant trans fatty acids and risk of coronary heart disease." International Journal of Epidemiology. 2008. 37:173-182.]
[48. Belury MA. "Dietary Conjugated Linoleic Acid in Health: Physiological Effects and Mechanisms of Action." Annual Review of Nutrition. 2002. 22:505-531.]
[49. Kritchevsky D. "Antimutagenic and some other effects of conjugated linoleic acid. British Journal of Nutrition. 2000. 83:459-465.]
[50. Pariza MW, Park Y, Cook ME. "The biologically active isomers of conjugated linoleic acid." Progress in Lipid Research. 2001. 40:283-298.]
[51. Parodi PW. "Conjugated linoleic acid: An anticarcinogenic fatty acid present in milk fat." The Australian Journal of Dairy Technology. 1994. 49:93-97.]
[52. Salminen I, Mutanen M, Hauhiainen M, Aro A. "Dietary trans fatty acids increase conjugated linoleic acid levels in human serum." Nutritional Biochemistry. 1998. 9:93-98.]
[53. French P, Stanton C, Lawless F, O'Riordan G, Monahan FJ, Caffrey PJ, Moloney AP. "Fatty acid composition, including conjugated linoleic acid, of intramuscular fat from steers offered grazed grass, grass silage, or concentrate-based diets." Journal of Animal Science. 2000. 78:2849-2855.]
[54. Ravnskov U. "The Questionable Role of Saturated and Polyunsaturated Fatty Acids in Cardiovascular Disease." Journal of Clinical Epidemiology. 1998. 51(6):443-460.]
[55. Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. "Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease." The American Journal of Clinical Nutrition. 2010. 91(3):535-546.]
[56. Ravnskov U. "The fallacies of the lipid hypothesis." Scandanavian Cardiovascular Journal. 2008. 42(4):236-239.]
[57. German JB, Dillard CJ. "Saturated fats: what dietary intake?." American Journal of Clinical Nutrition. 2004. 80(3):550-559.]
[58. Ravnskov U. "A hypothesis out-of-date: The diet-heart idea." Journal of Clinical Epidemiology. 2002. 55:1057-1063.]
[59. Ramsden CE, Faurot KR, Carrera-Bastos P, Cordain L, De Lorgeril M, Sperling LS. "Dietary Fat Quality and Coronary Heart Disease Prevention: A Unified Theory based on Evolutionary, Historical, Global, and Modern Perspectives." Current Treatment Options in Cardiovascular Medicine. 2009. 11:289-301.]
[60. Gillman MW, Cupples A, Millen BE, Ellison RC, Wolf PA. "Inverse Association of Dietary Fat With Development of Ischemic Stroke in Men." Journal of the American Medical Association. 1997. 278(24):2145-2150.]
[61. Mozaffarian D, Rimm EB, Herrington DM. "Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women. American Journal of Clinical Nutrition. 2004. 80(5):1175-1184.]
[62. Pietinen P, Ascherio A, Korhonen P, Hartman AM, Willett WC, Albanes D, Virtamo J. "Intake of Fatty Acids and Risk of Coronary Heart Disease in a Cohort of Finnish Men." American Journal of Epidemiology. 1997. 145(10):876-887.]
[63. Klevay LM. "Ischemic Heart Disease as Deficiency Disease." Cellular and Molecular Biology. 2004. 50(8):877-884.]
[64. Castelli WP. "Concerning the Possibility of a Nut." Archives of Internal Medicine. 1992. 152(7):1371-1372.]
[65. Ravnskov U. "Quotation Bias in Reviews of the Diet-Heart Idea." Journal of Clinical Epidemiology. 1995. 48(5):713-719.]
[66. Taubes G. "The Soft Science of Dietary Fat." Science. 2001. 291(5513):2536-2545.]
[67. Hodson L, Skeaff CM, Fielding BA. "Fatty acid composition of adipose tissue and blood in humans and its use as a biomarker of dietary intake." Progress in Lipid Research. 2008. 47(5):348-380.]
[68. Beynen AC, Hermus RJJ, Hautvast JGAJ. "A mathematical relationship between the fatty acid composition of the diet and that of the adipose tissue in man." American Journal of Clinical Nutrition. 1980. 33:81-85.]
[69. Malcom GT, Bhattacharyya AK, Velez-Duran M, Guzman MA, Oalmann MO, Strong JP. "Fatty acid composition of adipose tissue in humans: differences between subcutaneous sites." American Journal of Clinical Nutrition. 1989. 50:288-291.]
[70. Tortora GJ, Derrickson B. Principles of Anatomy and Physiology (12th ed.). 2009. Hoboken, NJ: Wiley.]
[71. Schuck S, Honsho M, Ekroos K, Shevchenko A, Simons K. "Resistance of cell membranes to different detergents." Proceedings of the National Academy of Sciences of the United States of America. 2003. 100(10):5795-5800.]
[72. Brown DA, London E. "Structure and Function of Sphingolipid- and Cholesterol-rich Membrane Rafts." Journal of Biological Chemistry. 2000. 275:17221-17224.]
[73. Ohvo-Rekila H, Ramstedt B, Leppimaki P, Slotte JP. "Cholesterol interactions with phospholipids in membranes." Progress in Lipid Research. 2002. 41:66-97.]
[74. O'Brien JS, Sampson EL. "Fatty acid and fatty aldehyde composition of the major brain lipids in normal human gray matter, white matter, and myelin." Journal of Lipid Research. 1965. 6:545-551.]
[75. Garbay B, Heape AM, Sargueil F, Cassagne C. "Myelin synthesis in the peripheral nervous system." Progress in Neurobiology. 2000. 61(3):267-304.]
[76. Veldhuizen R, Nag K, Orgeig S, Possmayer F. "The role of lipids in pulmonary surfactant." Molecular Basis of Disease. 1998: 1408(2-3):90-108.]
[77. Ding J, Takamoto DY, von Nahmen A, Lipp MM, Lee KYC, Waring AJ, Zasadzinski JA. "Effects of Lung Surfactant Protens, SP-B and SP-C, and Palmitic Acid on Monolayer Stability." Biophysical Journal. 2001. 80:2262-2272.]
[78. Bringezu F, Ding J, Brezinski G, Zasadzinski JA. "Changes in Model Lung Surfactant Monolayers Induced by Palmitic Acid." Langmuir. 2001. 17(15):4641-4648.]
[79. Drake DR, Brogden KA, Dawson DV, Wertz PW. "Antimicrobial lipids at the skin surface. Journal of Lipid Research. 2008. 49:4-11.]
[80. Marounek M, Skrivanova E, Rada V. "Susceptibility of Escherichia coli to C2-C18 Fatty Acids." Folia Microbiologica. 2003. 48(6):731-735.]
[81. Bergsson G, Arnfinnsson J, Steingrimsson O, Thormar H. "In Vitro Killing of Candida albicans by Fatty Acids and Monoglycerides." Antimicrobial Agents and Chemotherapy. 2001. 45(11):3209-3212.]
[82. Kabara JJ, Swieczkowski DM, Conley AJ, Truant JP. "Fatty Acids and Derivatives as Antimicrobial Agents." Antimicrobial Agents and Chemotherapy. 1972. 2(1):23-38.]
[83. Isaacs CE, Litov RE, Thormar H. "Antimicrobial activity of lipids added to human milk, infant formula, and bovine milk." Journal of Nutritional Biochemistry. 1995. 6(7):362-366.]
[84. Downing DT. "Lipid and protein structures in the permeability barrier of mammalian epidermis." Journal of Lipid Research. 1992. 33:301-313.]
[85. Lampe MA, Williams ML, Elias PM. "Human epidermal lipids: characterization adn modulations during differentiation." Journal of Lipid Research. 1983. 24:131-140.]
[86. Lampe MA, Burlingame AL, Whitney J, Williams ML, Brown BE, Roitman E, Elias PM. "Human stratum corneum lipids: characterization and regional variations." Journal of Lipid Research. 1983. 24:120-130.]
[87. James AT, Wheatley VR. "Studies of Sebum." Biochemical Journal. 1956. 63(2):269-273.]
[88. Ballard FB, Danforth WH, Naegle S, Bing RJ. "Myocardial Metabolism of Fatty Acids. Journal of Clinical Investigation. 1960. 39(5):717-723.]
[89. Wiseneski JA, Gertz EW, Neese RA, Mayr M. "Myocardial Metabolism of Free Fatty Acids." Journal of Clinical Investigation. 1987. 79:359-366.]
[90. Most AS, Brachfeld N, Coblin R, Wahren J. "Free Fatty Acid Metabolism of the Human Heart at Rest." Journal of Clinical Investigation. 1969. 48:1177-1188.]
[91. barger PM, Kelly DP. "PPAR Signaling in the Control of Cardiac Energy Metabolism." Trends in Cardiovascular Mecidin. 2000. 10(6):238-245.]
[92. Rothlin ME, Bing RJ. "Extraction and Release of Individual Free Fatty Acids by the Heart and Fat Depots." Journal of Clinical Investigation. 1961. 40(8):1380-1386.]
[93. Silaste ML, Rantala M, Alfthan G, Aro A, Witztum JL, Kesaniemi YA, Horkko S. "Changes in Dietary Fat Intake Alter Plasma Levels of Oxidized Low-Density Lipoprotein and Lipoprotein(a)." Atherosclerosis, Thrombosis, and Vascular Biology. 2004. 24:498-503.]
[94. Kraus WE, Houmard JA, Duscha BD, Knetzger KJ, Wharton MB, McCartney JS, Bales CW, Henes S, Samsa GP, Otvos JD, Julkarni KR, Slentz CA. "Effects of the Amount and Intensity of Exercise on Plasma Lipoproteins." New England Journal of Medicine. 2002. 347(19):1483-1492.]
[95. Huttunen JK, Lansimies E, Voutilainen E, Ehnholm C, Hietanen E, Penttila I, Siitonen O, Rauramaa R. "Effect of Moderate Physical Exercise on Serum Lipoproteins." Circulation. 1979. 60:1220-1229.]
[96. Rosenman RH. "The Independent Roles of Diet and Serum Lipids in the 20th-century Rise and Decline of Coronary Heart Disease Mortality." Integrative Physiological and Behavioral Science. 1993. 28(1):84-98.]
[97. Anderson A, Skakkebaek NE. "Exposure to exogenous estrogens in food: possible impact on human development and health." European Journal of Endocrinology. 1999. 140:477-485.]
[98. Galbraith H. "Hormones in international meat production: biological, sociological and consumer issues." Nutrition Research Reviews. 2002. 15:293-314.]
[99. Moishezon-Blank N. "Commentary on the Possible Effect of Hormones in Food on Human Growth." Medical Hypothesis. 1992. 38:273-277.]

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