Research Abstracts
Interplay of walnut consumption, changes in circulating miRNAs and reduction in LDL-cholesterol in elders.
Gil-Zamorano, J., M. Cofán, M.C. López de Las Hazas, T. García-Blanco, A. García-Ruiz, M. Doménech, M. Serra-Mir, I. Roth, C. Valls-Pedret, S. Rajaram, J. Sabaté, E. Ros, A. Dávalos, A. Sala-Vila, 2022. Interplay of walnut consumption, changes in circulating miRNAs and reduction in LDL-cholesterol in elders. Nutrients. 14(7):1473. https://doi.org/10.3390/nu14071473
The mechanisms underlying the lipid-lowering effect of nuts remain elusive. This study explores whether one-year supplementation with walnuts decreases LDL-cholesterol (LDL-C) by affecting the expression of circulating microRNAs (c-miRNA). In this sub-study of the Walnuts and Healthy Aging (WAHA) trial, we obtained fasting serum at baseline and at 1 year from 330 free-living participants (63–79 year, 68% women), allocated into a control group (CG, abstinence from walnuts, n = 164) and a walnut group (WG, 15% of daily energy as walnuts, ~30–60 g/day, n = 166). Participants in the WG showed a 1 year decrease in LDL-C (−9.07, (95% confidence interval: −12.87; −5.73) mg/dL; p = 0.010 versus changes in the CG). We conducted a miRNA array in eight randomly selected participants in the WG who decreased in LDL-C. This yielded 53 c-miRNAs with statistically significant changes, 27 of which survived the correction for multiple testing. When validating them in the full population, statistical significance lasted for hsa-miR-551a, being upregulated in the WG. In mediation analysis, the change in hsa-miR-551a was unrelated to LDL-C decrease. Long-term supplementation with walnuts decreased LDL-C independently of the changes in c-miRNA. The hsa-miR-551a upregulation, which has been linked to a reduced cell migration and invasion in several carcinomas, suggests a novel mechanism of walnuts in cancer risk.