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ARS Home » Pacific West Area » Davis, California » Western Human Nutrition Research Center » Diet, Microbiome and Immunity Research » Research » Publications at this Location » Publication #179685
Title: FATTY ACID PROFILES OF LIVER, ADIPOSE TISSUE, SPLEEN, AND HEART OF MICE FED DIETS CONTAINING T10, C-12-, AND C9, T11-CONJUGATED LINOLEIC ADIC

Author
item Kelley, Darshan
item Bartolini, Giovanni
item Newman, John
item VEMURI, MADHURI - UC DAVIS, NUTR. DEPT.
item Mackey, Bruce

Submitted to: Prostaglandins Leukotrienes and Essential Fatty Acids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/13/2006
Publication Date: 2/14/2006
Citation: Kelley, D.S., Bartolini, G.L., Newman, J.W., Vemuri, M., Mackey, B.E. 2006. FATTY ACID PROFILES OF LIVER, ADIPOSE TISSUE, SPLEEN, AND HEART OF MICE FED DIETS CONTAINING T10, C-12-, AND C9, T11-CONJUGATED LINOLEIC ADIC. Prostaglandins Leukotrienes and Essential Fatty Acids. 74:331-338.

Interpretive Summary: Conjugated linoleic acid (CLA) is a collective term for a group of isomers of linoleic acid that have conjugated double bonds. There are several isomers of CLA and most published studies have used a mixture of the isomers. The risks and benefits of individual isomers are not known. Even if there are several risks associated with CLA supplementation and the effects of individual isomers have not been defined, supplementation of human diets with CLA to reduce body fat, to increase lean mass and for other perceived health benefits is on the increase. The purpose of this study was to examine the effects of two purified isomers of dietary CLA (c9, t11-CLA, and t10, c12-CLA) supplements on the amount and fatty acid profiles of mouse liver, adipose tissue, spleen and heart lipids. Eight week old, female mice (n=6/group) were fed either a control diet, or diets supplemented with 0.5% c9, t11-CLA or t10, c12-CLA isomers for eight weeks. Weights and lipid content of hearts and spleens were not altered by both isomers; c9 t11-CLA did not alter these parameters in liver and adipose tissue as well. In animals fed diets containing t10, c12-CLA, the total liver weight and lipid content were increased by two and four fold as compared to the corresponding values in the control group, respectively; both the weight and lipid contents of retroperitoneal adipose tissue were reduced approximately to one-third of those in the control group. Both isomers significantly altered fatty acid concentrations of several fatty acids. The most dramatic and alarming effect of the t10, c12-CLA was a greater than 25% reduction in the heart omega- 3 fatty acid (DHA) with concomitant 6-fold increase in the spleen DHA. This increase in spleen DHA was accompanied by a reduction in arachidonic acid (omega-6 fatty acid) to less than 5% of that found in the control group. C9, t11-CLA did not alter the DHA content of the hearts but reduced the spleen DHA to about 10% of that found in the control group. Since omega -3 fatty acids are known to improve cardiovascular health, the dramatic reduction in heart tissue DHA may have serious health consequences.

Technical Abstract: The purpose of this study was to examine the incorporation of two purified isomers of dietary CLA (c9, t11-CLA, and t10, c12-CLA) into tissue (liver, adipose tissue, spleen and heart) lipids, and their effects on the tissue lipid content and fatty acid profiles. Eight week old, female mice (n=6/group) were fed either a control diet, or diets supplemented with 0.5% c9, t11-CLA or t10, c12-CLA isomers for eight weeks. Incorporation of c9, t11-CLA was greater than that of t10, c2-CLA in all tissue lipids, with the highest being in adipose tissue lipids (4%) and lowest in the spleen lipids (undetectable). Weights and lipid content of hearts and spleens were not altered by both isomers; c9 t11-CLA did not alter these parameters in liver and adipose tissue as well. In animals fed diets containing t10, c12-CLA, the total liver weight and lipid content were two and four times greater than the corresponding values in the control group, respectively; both the weight and lipid contents of retroperitoneal adipose tissue were reduced approximately to one-third of those in the control group. Both isomers significantly altered the concentrations of several fatty acids in all tissues. Concentration of 22:6n-3 (DHA) in the heart and spleen lipids from the control group were 13.1±0.8, and 2.8±0.3 (Mean±SEM) wt% respectively. In the t10, c12-CLA group the concentration of DHA in heart was reduced to 9.7±0.4, and in the spleen it was increased to 20.4±1.4 wt%. 20:4n-6 (AA) in the spleen was reduced from 17.3±0.7 to 0.6±0.1 wt%. c9, t11-CLA did not alter the wt% of DHA in heart lipids, but it reduced the DHA to 0.3±0.0 and increased the AA to 27.9 wt % in spleen lipids. While concentrations of some other fatty acids also changed significantly, alterations in DHA and AA metabolism may have significant health consequences. These changes may increase the risk for cardiovascular and other inflammatory diseases.