Interplay of Walnut Consumption, Changes in Circulating miRNAs and Reduction in LDL-Cholesterol in Elders.
Author(s): Gil-Zamorano J, Cofán M, López de Las Hazas MC, García-Blanco T, García-Ruiz A, Doménech M, Serra-Mir M, Roth I, Valls-Pedret C, Rajaram S, Sabaté J, Ros E, Dávalos A, Sala-Vila A
Publication: Nutrients, 2022, Vol. 14, Page
PubMed ID: 35406086 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to compare cholesterol, triglyceride and alpha-linolenic acid (ALA) levels and microRNA (miRNA, miR) profiles in serum from patients before and one year after a dietary intervention that included either abstaining from walnuts or eating a diet in which walnuts accounted for 15% of energy intake.
Conclusion of Paper
Compared to patients that abstained from walnuts for a year, those that received 15% of energy intake from walnuts had serum with a higher percentage of ALA (relative to total fatty acids), and lower concentrations of total and of low density lipoprotein (LDL) cholesterol. Levels of total cholesterol and triglycerides did not differ between dietary groups at baseline or after a year on the diet. Although 27 miRNAs were identified to be differentially expressed between serum obtained before and after 1 year on the high walnut diet in the initial study, only miR-551a was differentially expressed between dietary groups when the entire cohort was evaluated.
Studies
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Study Purpose
The purpose of this paper was to compare cholesterol, triglyceride and ALA levels and miRNA profiles in serum from patients before and one year after a dietary intervention that included either abstaining from walnuts or eating a diet in which walnuts accounted for 15% of energy intake. Blood was collected from healthy fasting elderly patients before dietary intervention and after one year of abstinence from walnuts (164 patients; 111 females, 53 males), or after one year on a diet that consisted of 15% of energy intake from walnuts (166 patients; 114 female 52 males). Serum was obtained by centrifugation (details not provided) and stored at -80°C. Concentrations of alpha-linolenic acid (ALA), total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol and triglycerides were measured by unspecified methods. miRNA was extracted from serum using the miRCURY RNA Isolation Kit. To identify miRNA affected by dietary consumption of walnuts, in eight patients the levels of 752 miRNA were quantified using the miRCURY LNA miRNA miRNome PCR Human panel in serum collected before and after one year on the walnut diet; patients were selected based on reduced LDL and no reported change in physical activity. Identified miRNAs were quantified in the serum of all 330 participants by real-time PCR using Pick-&-Mix microRNA PCR Panels.
Summary of Findings:
Baseline (before diet intervention) percentages of fatty acids that were ALA, and concentrations of total cholesterol and LDL cholesterol were comparable between dietary groups. However, patients that were on a high walnut diet for 1 year (walnuts accounted for 15% of energy intake) had serum with a higher ALA percentage (P<0.001) and a lower concentration of total and LDL cholesterol (P=0.01 and P=0.005) than patients who abstained from walnuts for one year. There were no differences between the two dietary groups for HDL cholesterol and triglyceride concentrations at baseline or after 1 year on the diet.
Compared to baseline levels from the same individuals, 53 miRNAs were differentially expressed in serum after patients were on a diet high in walnuts for 1 year (P<0.05); 36 miRNAs were upregulated and 17 miRNAs were downregulated in serum from patients after a 1 year diet high in walnuts. After correction for multiple testing, 17 miRNAs were upregulated and 10 miRNAs were downregulated relative to baseline serum samples (P<0.05); thirteen of these miRNAs as well as two additional miRNAs (miR-192-5p and miR-330-3p) were chosen for further analysis. In the expanded analysis, only miR-551a was differentially expressed after 1 year on a diet high in walnuts relative to baseline (pre-dietary intervention) serum levels (P=0.006). This change was not significantly related to the observed change in LDL cholesterol in the same patients.
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Normal
Platform:
Analyte Technology Platform RNA Real-time qRT-PCR Small molecule Clinical chemistry/auto analyzer Lipid Clinical chemistry/auto analyzer Steroid Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Acquisition Time of biospecimen collection Before start of diet
After 1 year on the diet
Preaquisition Patient diet Diet with 15% of energy intake from walnuts
Abstinence from walnuts