Cook M E: The biologically active isomers of conjugated linoleic acid

Department of Animal Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States
Progress in Lipid Research (Impact Factor: 10.02). 08/2001; 40(4):283-98. DOI: 10.1016/S0163-7827(01)00008-X
Source: PubMed


Numerous physiological effects are attributed to conjugated linoleic acid (CLA). The purpose of this presentation is to consider these effects with respect to the cis-9,trans-11 and trans-10,cis-12 CLA isomers. We review previously published data and present new findings that relate to underlying biochemical mechanisms of action. Both isomers are natural products. The cis-9,trans-11 isomer is the principal dietary form of CLA, but the concentrations of this isomer and the trans-10,cis-12 isomer in dairy products or beef vary depending on the diet fed to cows or steers, respectively. The trans-10,cis-12 CLA isomer exerts specific effects on adipocytes, in particular reducing the uptake of lipid by inhibiting the activities of lipoprotein lipase and stearoyl-CoA desaturase. The trans-10,cis-12 CLA isomer also affects lipid metabolism in cultured Hep-G2 human liver cells, whereas both the cis-9,trans-11 and trans-10,cis-12 CLA isomers appear to be active in inhibiting carcinogenesis in animal models. We present new findings indicating that the cis-9,trans-11 CLA isomer enhances growth and probably feed efficiency in young rodents. Accordingly, the effects of CLA on body composition (induced by trans-10,cis-12 CLA) and growth/feed efficiency (induced by cis-9,trans-11 CLA) appear to be due to separate biochemical mechanisms. We also show that a 19-carbon CLA cognate (conjugated nonadecadienoic acid, CNA) inhibits lipoprotein lipase activity as effectively as CLA in cultured 3T3-L1 adipocytes. Presumably, CNA is metabolized differently than the 18-carbon CLA isomers, so this finding indicates direct activity of the administered compound as opposed to acting via a metabolite.

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    • "Conjugated linoleic acid (CLA) consists of a group of positional and geometric isomers of linoleic acid with 2 conjugated double bonds at various carbon positions in the fatty acid chain. The most frequently studied CLA isomers for biological activity are the cis–9, trans–11 and the trans–10, cis–12 (Pariza et al., 2001). Studies have found that CLA has beneficial immunomodulatory properties (Lai et al., 2005; He et al., 2007) and positively influences body composition (Sirri et al., 2003; Cordero et al., 2010) preventing fat accumulation. "
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    ABSTRACT: The effects of lutein and conjugated linoleic acid (CLA) on growth performance and immune response of broiler chickens were evaluated in the presence and absence of Salmonella lipopolysaccharide (LPS) immune challenge. Cobb chicks (360; 1 to 22 d of age) were used in a 3 × 2 factorial arrangement of CLA (0, 1, and 2%) and lutein (0 and 50 mg/kg) dietary levels. At d 8 and 15, birds were injected with BSA to assess IgY production. At d 20, birds were injected with LPS. Samples of liver, spleen, and duodenum were collected at 3 and 16 h post-LPS challenge for RT-qPCR analysis of RXRα, RXRγ, PPARα, PPARγ, TLR-4, IL-1β, IL-2, IL-10, and IL-12 gene expression. CLA decreased BW, BW gain (BWG), and G:F from d 1 to 20, but these effects were reversed when lutein was included in the 1% CLA diet (P < 0.001). The production of IgY anti-BSA increased following a 2% CLA supplementation (P < 0.01). LPS increased the liver:BW ratio at 3 h post-injection (P < 0.001) and decreased BWG at 3, 16, and 40 h (P < 0.001). Lutein decreased plasmatic nitric oxide levels (P < 0.01). LPS downregulated PPARα mRNA in the duodenum (P = 0.02) and liver (P = 0.04), and PPARγ (P = 0.01) and RXRα (P = 0.08) in the spleen; these effects were not reversed by CLA or lutein as initially hypothesized. Although LPS upregulated IL-1β (P = 0.02) and IL-12 (P = 0.07) expression, lutein downregulated these pro-inflammatory cytokines in the liver (P = 0.03 and P = 0.07, respectively). Lutein decreased splenic (P = 0.09) but increased hepatic (P = 0.06) TLR-4 mRNA. A dietary CLA supplementation of 2% increased hepatic RXRα (P = 0.10). In conclusion, CLA decreased broiler chicken growth performance, but lutein could prevent this negative effect (depending on CLA dose). Lutein had an anti-inflammatory effect, and a 2% CLA supplementation improved the humoral immune response.
    Full-text · Article · Nov 2015 · Poultry Science
    • "Although many positional and geometric isomers of CLA exist, cis- 9,trans-11 CLA (9,11 CLA) and trans-10,cis-12 CLA (10,12 CLA) are the most biologically active forms (Pariza et al., 2001). Moreover, 9,11 CLA is the most common CLA isomer in the diet of humans (Pariza et al., 2001), in which isomers of CLA (primarily as 9,11 CLA) constitute a small, but significant, component of fats derived from the meat and milk of ruminant animals (Chin et al., 1992). The combined levels of CLA in most dairy products range from 2.5 to 7.0 mg/g of fat (Lin et al., 1995), whereas meat from ruminants contains 2.7 to 5.6 mg of CLA/g of fat (Chin et al., 1992). "
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    ABSTRACT: The mammary gland (MG) is one of a few organs that undergoes most of its growth after birth. Much of this development occurs concurrently with specific reproductive states, such that the ultimate goal of milk synthesis and secretion is coordinated with the nutritional requirements of the neonate. Central to the reproductive-MG axis is its endocrine regulation, and pivotal to this regulation is the ovarian secretion of estrogen (E). Indeed, it is widely accepted that estrogens are essential for growth of the MG to occur, both for ductal elongation during puberty and for alveolar development during gestation. As the factors regulating MG development continually come to light from the fields of developmental biology, lactation physiology, and breast cancer research, a growing body of evidence serves as a reminder that the MG are not as exclusively dependent on estrogens as might have been thought. The objective of this review is to summarize the state of information regarding our understanding of how estrogen (E) has been implicated as the key regulator of MG development, and to highlight some of the alternative E-independent mechanisms that have been discovered. In particular, we review our findings that dietary trans-10,cis-12 conjugated linoleic acid promotes ductal elongation and that the combination of progesterone (P) and prolactin (PRL) can stimulate branching morphogenesis in the absence of E. Ultimately, these examples stand as a healthy challenge to the question of just how important estrogens are for MG development. Answers to this question, in turn, increase our understanding of MG development across all mammals and the ways in which it can affect milk production.
    No preview · Article · Oct 2015 · Journal of Dairy Science
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    • "The use of low protein diets is gaining interest because of environmental concerns and the increasing cost of protein sources (Schiavon et al. 2010 and 2013; Gallo et al. 2015). Conjugated linoleic acid isomers (CLA) content in animal products has gained attention primarily for the beneficial effect of these molecules on human health (Pariza et al. 2001) and have shown a favourable interaction with dietary protein reduction in young bulls fattening (Schiavon et al., 2012; Schiavon and Bittante, 2012). A dietary supply of these isomers decreased milk fat content in dairy cows (Glasser et al., 2010) and worsened milk coagulation properties (MCP) in ewe milk (Bittante et al., 2014). "

    Full-text · Dataset · Oct 2015
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