PUFA almost fully blocks protein synthesis and the effect is correlated with unsaturation; SFA do not
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Another study demonstrating direct negative effect of PUFA on human health. Namely, inhibition by PUFA of protein synthesis, which is vital for tissue/organ growth/repair. Moreover, the degree of protein synthesis inhibition apparently depends on the degree of PUFA unsaturation. As was the case with the recent post about PUFA increasing platelet aggregation and serotonin release, saturated fatty acids (SFA) did not inhibit protein synthesis. Also, just as in the platelet/serotonin study, the inhibition of protein synthesis by PUFA was a direct effect of the unmodified lipids and did not depend on their downstream conversion into the well-known inflammatory metabolites derived from PUFA.
https://pubmed.ncbi.nlm.nih.gov/1546963/
“…Optimal translation initiation in intact mammalian cells requires sequestered intracellular Ca2+. Arachidonic acid, which releases sequestered Ca2+ from cells and isolated organelles, was studied to assess its potential role in the regulation of protein synthesis via Ca2+ mobilization. Unsaturated fatty acids at microM concentrations inhibited protein synthesis in intact GH2 pituitary, C6 glial tumour and HeLa cells in a manner dependent on degree of unsaturation and cell number. Arachidonate was generally the most, and the fully saturated arachidic acid the least, potent of the fatty acids tested. At 2 x 10(6) GH3 cells/ml, amino incorporation into a broad spectrum of polypeptides was inhibited by 80-90% by 10-20 microM fatty acid. Inhibition was maximal at 4-8 min and was attenuated by 1-2 h and more pronounced at lower pH. Protein synthesis was maximally inhibited when arachidonate mobilized approx. 40% of cell-associated Ca2+. At lower concentrations (10 microM) arachidonate suppressed translational initiation, with the inhibition being reversed as extracellular Ca2+ concentrations were increased to supraphysiological values. At higher concentrations (20 microM) arachidonate inhibited peptide-chain elongation in a Ca(2+)-independent manner. Arachidonate also blocked elongation in reticulocyte lysates. The effects of arachidonate in intact cells were reversible with time via its metabolism or by washes containing BSA. Sufficient arachidonate appears to be synthesized during ischaemic stress to inhibit translation by either mechanism.”