Conjugated linoleic acid in adipose tissue and risk of myocardial infarction.
BACKGROUND
Despite the high saturated fat content of dairy products, no clear association between dairy product intake and risk of myocardial infarction (MI) has been observed. Dairy products are the main source of conjugated linoleic acid (CLA; 18:2n-7t), which is produced by the ruminal biohydrogenation of grasses eaten by cows. Pasture-grazing dairy cows have more CLA in their milk than do grain-fed cows. Some animal models have reported beneficial effects of CLA on atherosclerosis.


OBJECTIVE
The objective was to determine the association between the 9c,11t-CLA isomer in adipose tissue and risk of MI.


METHODS
The studied population consisted of 1813 incident cases of a first nonfatal acute MI and 1813 population-based controls matched for age, sex, and area of residence. All subjects lived in Costa Rica-a country that uses traditional pasture-grazing for dairy cows. Conditional logistic regression was used to estimate multivariate odds ratios and 95% CIs.


RESULTS
Adipose tissue 9c,11t-CLA was associated with a lower risk of MI in basic and multivariate models. Compared with the lowest quintile, odds ratios and 95% CIs were 0.80 (0.61, 1.04) for the second, 0.86 (0.64, 1.14) for the third, 0.62 (0.46, 0.84) for the fourth, and 0.51 (0.36, 0.71) for the fifth quintiles (P for trend <0.0001). Dairy intake was not associated with risk of MI, despite a strong risk associated with saturated fat intake.


CONCLUSIONS
9c,11t-CLA, which is present in meaningful amounts in the milk of pasture-grazed cows, might offset the adverse effect of the saturated fat content of dairy products.
Smit
Liesbeth A
LA
Department of Nutrition Harvard School of Public Health, Boston, MA, USA.
Baylin
Ana
A
Campos
Hannia
H
D000273:Adipose Tissue / Q000378:metabolism*; D000368:Aged; D003364:Costa Rica / Q000453:epidemiology; D048909:Diabetes Complications / Q000453:epidemiology; D004032:Diet; D004562:Electrocardiography; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000453:epidemiology; D006973:Hypertension / Q000453:epidemiology; D007182:Income; D044243:Linoleic Acids, Conjugated / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D008958:Models, Molecular; D009203:Myocardial Infarction / Q000453:epidemiology*; D012008:Recurrence; D012307:Risk Factors; D049629:Waist-Hip Ratio
D044243:Linoleic Acids, Conjugated
Crit Rev Food Sci Nutr. 2006;46(6):479-88
16864141
J Nutr. 2005 Nov;135(11):2674-9
16251629
Eur J Clin Nutr. 2003 Nov;57(11):1447-57
14576758
J Clin Hypertens (Greenwich). 2008 Jul;10(7 Suppl 2):3-11
18607145
Curr Opin Lipidol. 2006 Feb;17(1):1-10
16407709
Eur J Clin Nutr. 2006 Feb;60(2):236-44
16267503
Biochem Cell Biol. 2008 Aug;86(4):293-301
18756324
Atherosclerosis. 2006 Jul;187(1):40-9
16182300
J Biol Chem. 1966 Mar 25;241(6):1350-4
5936712
J Nutr. 2002 May;132(5):940-5
11983818
J Lipid Res. 1999 Aug;40(8):1426-33
10428978
Nat Rev Cardiol. 2009 Oct;6(10):621-30
19687790
Circulation. 2009 Aug 25;120(8):649-55
19667235
Am J Clin Nutr. 1999 Jul;70(1):21-7
10393134
Am J Epidemiol. 2001 Dec 15;154(12):1126-35
11744518
Am J Clin Nutr. 2002 Oct;76(4):750-7
12324287
Lipids. 2004 Jul;39(7):611-6
15588017
Am J Clin Nutr. 2002 Sep;76(3):504-10
12197992
Hypertension. 2007 May;49(5):1063-9
17372031
Circulation. 2007 Apr 10;115(14):1858-65
17389261
Lipids. 1997 Aug;32(8):853-8
9270977
Nutr Rev. 2008 Jul;66(7):415-21
18667017
Eur J Cardiovasc Prev Rehabil. 2006 Oct;13(5):791-7
17001220
Am J Clin Nutr. 2007 Oct;86(4):929-37
17921367
J Nutr. 2001 May;131(5):1548-54
11340114
Crit Rev Food Sci Nutr. 2005;45(6):463-82
16183568
Diabetes. 2007 Mar;56(3):574-82
17327424
Curr Opin Lipidol. 2006 Feb;17(1):22-7
16407712
Am J Clin Nutr. 2004 Jun;79(6 Suppl):1169S-1174S
15159253
J Dairy Sci. 1999 Oct;82(10):2146-56
10531600
Food Nutr Bull. 2008 Sep;29(3):172-85
18947030
J Lipid Res. 1966 Jan;7(1):103-11
5900208
Am J Clin Nutr. 2008 Jun;87(6):1914-25
18541585