Possible Interaction: Linoleic Acid and Conjugated Linoleic Acid

“Feeding cattle linoleic acid-rich oils for extended periods of time increases the CLA content of beef.”

“In established rodent tumors and human cancer cell lines, conjugated dienoic isomers of linoleic acid CLA ) suppress the growth-stimulating effects of linoleic acid (LA) and its metabolism to the mitogenic agent, 13-hydroxyoctadecadienoic acid (13-HODE).”

“The inhibitory effect is reversible with either pertussis toxin (PTX) or 8-Br-cAMP suggesting that CLA isomers differentially inhibit LA uptake and metabolism and cell proliferation in human breast cancer in vivo via a receptor-mediated, PTX-sensitive pathway.”

“The results demonstrated that two CLA isomers [10t, 12c-CLA>9t, 11t-CLA] caused a dose-dependent inhibition of LA uptake, cAMP content, 13-HODE formation, Erk 1/2 activity, and [(3)H]thymidine incorporation into tumor DNA; 9c, 11t-CLA showed no effect.”

“Accordingly, CLA metabolism interferes with LA metabolism.”

“Rather, linoleic acid antagonized the protective action of CLA isomers in a noncompetitive fashion.”

“Moreover, supplementation with 20 microM LA and 20 microM arachidonic acid profoundly interfered with the inhibitory effect of CLA in HepG2.”

“Although biological differences appeared to be modest (5-20% of control), the fact that LA and CLA treatment resulted in significant biological effects at physiologic concentrations is relevant, since most human cancers require years to develop.”

“ Linoleic acid stimulated cancer cell growth, while CLA was inhibitory.”

“ Linoleic acid stimulated the growth and [3H]thymidine incorporation of normal HMEC and MCF-7 cancer cells, while CLA was inhibitory.”

“Therefore, we hypothesized that CLA improves glucose utilization and insulin sensitivity in rats fed different levels of dietary linoleic acid (LA).”

“Mice receiving the 0.2% and 0.6% dose of 10,12 CLA plus linoleic acid or the CLA isomer mixture had decreased white adipose tissue (WAT) and brown adipose tissue (BAT) mass and increased incorporation of CLA isomers in epididymal WAT and liver.”

“Moreover, addition of CLA isomers interfered in the conversion of linoleic and linolenic acids to higher metabolites due to competition of CLA isomers for the same enzymes (Δ6-, Δ5-, Δ4-desaturases and elongase).”