Scientific direction of NBF Lanes in cooperation with Prof. Sebastiano BANNI, University of Cagliari.
WHAT IS THE CLA
THE CONJUGATED LINOLEIC ACID (CLA) IS A LONG-CHAIN FATTY ACID
The conjugated linoleic acid (CLA) is a long-chain fatty acid formed by a mixture of several isomers; two particularly active forms have been identified: cis-9, trans-11 and trans-10, cis-12. CLA occurs naturally in dairy products and meat from ruminants.
HIGH NUMBER OF EXPERIMENTS FOR BIOLOGICAL ACTIVITY
The great attention paid to Conjugated Linoleic Acid (CLA) is due to the large number of experiments that have revealed several important biological activity of this long-chain fat acid such as:
Modulation of lipid metabolism
Anticancer activity
Modulation of the immune system
MODULATION OF LIPID MECHANISM
Reduction of adipose tissue
Particular attention was paid to CLA ability to alter body composition, reducing the accumulation of adipose tissue.The first experiments to test this activity were carried out on growing rats, in which there was a 50% reduction of total fat mass compared to control mice, by administering a diet containing 1% of conjugated linoleic acid.
CLA reduces by 50% the content of arachidonic acid in adipocytes
The CLA may also interfere with normal cellular mechanisms involved in the maturation of pre-adipocytes. It was observed that the CLA changes the profile and the content of fatty acids in adipocytes, in particular the content of arachidonic acid which is reduced by 50%. The latter is the precursor of prostaglandins PGE2.
Energy consumption regulation
The mechanisms by which CLA reduces fat deposits in normal-weight animals are to be found in the regulation of energy consumption. The results suggest that CLA improve metabolic percentages favoring a reduction in respiratory quotient, an increase in oxygen consumption associated with an increase of the oxidation of fats, but not of the carbohydrate.
MODULATION OF PROTEIN MECHANISM
CLA regulates the proliferation of lymphocytes, monocytes and macrophages
The CLA is able to influence the modulation of the immune response since it interferes with the production of eicosanoids. In fact, CLA is able to inhibit COX interfering with RNA messenger of the protein or its activity, and thus reducing the formation of eicosanoids; on the other hand it has been highlighted the link that CLA tightens with PPAR receptors at nucleus level. These receptors are widely expressed in the immune system and are involved in the regulation of several genes implicated in the proliferation of lymphocytes, monocytes and macrophages. It is believed that the mechanism by which CLA regulates the immune system is its ability to reduce, in the tissues, the level of arachidonic acid, the main substrate for the synthesis of Prostaglandin PGE2. The latter is a TNF-alpha regulator, a key factor in several disease states: carcinogenesis, atherosclerosis, obesity, inflammation and cachexia.
The CLA reduces the TNF-alpha secretion in macrophages
In macrophage cultures stimulated with endotoxin, the treatment with CLA reduce the TNF-alpha secretion compared to Linoleic Acid. Endotoxins are the components present in the cell membranes of Gram negative and can stimulate macrophages to secrete cytokines in particular TNF-alpha and IL-1 (Interleukin 1) both able to cause biochemical changes in other cells.
Increase of the cytotoxic activity of lymphocytes and protection from the typical organic deterioration of autoimmune diseases
The decrease of the negative effects produced by the administration of CLA is not due to immunosuppression, but to the increase of blastogenesis of lymphocytes, to their cytotoxic activity, the “killer” ability of macrophages and to protection by the final decay in case of autoimmune diseases.
In animal studies it was seen that the administration of CLA leads to an increase in suppressor T lymphocytes (CD8 +) and an improvement of the specific functions which they have mediated; from this it can be deduced that CLA has a direct effect on differentiation and cell growth.
A more recent study has suggested that the isomer c9, t11 is involved in increasing the number of CD8+ cells, while the isomer t10, c12 acts on the increase in T lymphocytes helper CD4+.
The CLA increases the production of IgA, IgG, IgM, reduces IgE production, stimulates the Th1 cytokines by lymphocytes
It was shown that CLA increases the production of IgA, IgG and IgM in rat serum and lymph cell cultures, while reducing the production of IgE, present when developing an allergic reaction of type I mediated by Th2 lymphocytes. Therefore it is believed that the administration of CLA in the diet stimulates cytokine synthesis by Th1 lymphocytes and inhibits Th2 lymphocytes. In people subjected to physical endurance tests, the administration of 6g / day for 28 days of CLA resulted in a 25% decrease of the ratio between neutrophils and lymphocytes in the circulation, while it is not noticed any change of this ratio in the control group.
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