Carter, S., A.M. Hill, L.C. Mead, H.Y. Wong, C. Yandell, J.D. Buckley, S.Y. Tan, G.B. Rogers, F. Fraysse, A.M. Coates, 2023. Almonds vs. carbohydrate snacks in an energy-restricted diet: Weight and cardiometabolic outcomes from a randomized trial. Obesity (Silver Spring). 31(10):2467-2481. https://doi.org/10.1002/oby.23860
Objective: This study evaluated weight and cardiometabolic outcomes after a 3-month energy-restricted diet (−30%) containing almonds (almond-enriched diet [AED]) or containing carbohydrate-rich snacks (nut-free control diet [NFD]) (Phase 1), followed by 6 months of weight maintenance (Phase 2). Methods: Participants (25–65 years old) with overweight or obesity (BMI 27.5–34.9 kg/m2) were randomly allocated to AED (n = 68) or NFD (n = 72). Results: Both groups lost weight during Phase 1 (p < 0.001) (mean [SE], −7.0 [0.5] kg AED vs. −7.0 [0.5] kg NFD, p = 0.858) and Phase 2 (p = 0.009) (−1.1 [0.5] kg AED vs. −1.3 [0.6] NFD, p = 0.756), with improvements in percentage lean mass after Phase 2 (4.8% [0.3%], p < 0.001). Reductions occurred in fasting glucose (−0.2 [0.07] mmol/L, p = 0.003), insulin (−8.1 [4.0] pmol/L, p = 0.036), blood pressure (−4.9 [0.8] mm Hg systolic, −5.0 [0.5] mm Hg diastolic, p < 0.001), total cholesterol (−0.3 [0.1] mmol/L), low-density lipoprotein (LDL) (−0.2 [0.1] mmol/L), very low density lipoprotein (−0.1 [0.03] mmol/L), and triglycerides (−0.3 [0.06] mmol/L) (all p < 0.001), and high-density lipoprotein increased (0.1 [0.02] mmol/L, p = 0.011) by the end of Phase 2 in both groups. There were group by time interactions for lipoprotein particle concentrations: very small triglyceride-rich (−31.0 [7.7] nmol/L AED vs. −4.8 [7.9] nmol/L NFD, p = 0.007), small LDL (−109.3 [40.5] nmol/L AED vs. −20.7 [41.6] nmol/L NFD, p = 0.017), and medium LDL (−24.4 [43.4] nmol/L AED vs. −130.5 [44.4] nmol/L NFD, p = 0.045). Conclusions: An energy-restricted AED resulted in weight loss and weight loss maintenance comparable to an energy-restricted NFD, and both diets supported cardiometabolic health. The AED resulted in greater improvements in some lipoprotein subfractions, which may enhance reductions in cardiovascular risk.
Yang, J., R. Lee, Z. Schulz, A. Hsu, J. Pai, S. Yang, S.M. Henning, J. Huang, J.P. Jacobs, D. Heber, Z. Li., 2023. Mixed nuts as healthy snacks: effect on tryptophan metabolism and cardiovascular risk factors. Nutrients. 15, 569; https://doi.org/10.3390/nu15030569.
We recently demonstrated that the consumption of mixed tree nuts (MTNs) during caloric restriction decreased cardiovascular risk factors and increased satiety. Tryptophan (Trp) metabolism has been indicated as a factor in cardiovascular disease. Here, we investigated the effect of MTNs on Trp metabolism and the link to cardiovascular risk markers. Plasma and stool were collected from 95 overweight individuals who consumed either MTNs (or pretzels) daily as part of a hypocaloric weight loss diet for 12 weeks followed by an isocaloric weight maintenance program for an additional 12 weeks. Plasma and fecal samples were evaluated for Trp metabolites by LC–MS and for gut microbiota by 16S rRNA sequencing. Trp–kynurenine metabolism was reduced only in the MTNs group during weight loss (baseline vs. week 12). Changes in Trp–serotonin (week 24) and Trp–indole (week 12) metabolism from baseline were increased in the MTNs group compared to the pretzel group. Intergroup analysis between MTN and pretzel groups does not identify significant microbial changes as indicated by alpha diversity and beta diversity. Changes in the relative abundance of genus Paludicola during intervention are statistically different between the MTNs and pretzel group with p < 0.001 (q = 0.07). Our findings suggest that consumption of MTNs affects Trp host and microbial metabolism in overweight and obese subjects.
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.
Kopecky, S.L., S. Alias, E. Klodas, P.J.H. Jones, 2022. Reduction in serum LDL cholesterol using a nutrient compendium in hyperlipidemic adults unable or unwilling to use statin therapy: a double-blind randomized crossover clinical trial. J. Nutr. 152(2), 458–465. https://doi.org/10.1093/jn/nxab375
Background: Many hyperlipidemic patients prescribed β-hydroxy-β-methylglutaryl coenzyme A reductase inhibitors (statins) are unable or unwilling to take them. A hedonically acceptable snack-based solution formulated from cholesterol-lowering food ingredients could represent a therapeutic alternative but has not been tested in this population. Objectives: To evaluate the effect of snacks containing a compendium of functional bioactives on fasting LDL cholesterol in statin candidates unwilling to use or intolerant to ≥1 statin drug. Secondary outcomes included changes in circulating total cholesterol (TC), triglycerides, HDL cholesterol, fasting glucose, insulin, and high-sensitivity C-reactive protein concentrations, as well as effects of single-nucleotide polymorphisms (SNPs) on outcome. Methods: This multicenter, randomized, double-blind, free-living crossover study was composed of 2 regimented phases of 4 wk each, separated by a 4-wk washout. Eighteen men and 36 women, with a mean ± SD age of 49 ± 12 y and mean ± SD LDL cholesterol of 131 ± 32.1 mg/dL, were instructed to ingest a variety of ready-to-eat snacks twice daily as a substitute for something they were consuming already. Other behavior changes were actively discouraged. Treatment products provided ≥5 g fiber, 1000 mg ω-3 (n-3) fatty acids, 1000 mg phytosterols, and 1800 μmol antioxidants per serving. Control products were calorie-matched like-items drawn from the general grocery marketplace. Serum lipids were measured at baseline and the end of each phase and compared using the ANOVA model. Compliance to study foods was confirmed by serum 18:3n-3 concentration assessment. Results: Comparing intervention phase endpoints, LDL cholesterol was reduced a mean ± SD of 8.80 ± 1.69% (P < 0.0001), and TC was reduced a mean ± SD of 5.08 ± 1.12% (P < 0.0001) by treatment foods compared with control foods, whereas effects on other analytes did not differ between treatments. SNPs were not significantly related to outcomes (P ≥ 0.230). Compliance with study foods was 95%. Conclusions: Consumption of hedonically acceptable snacks containing a compendium of cholesterol-lowering bioactive compounds can rapidly and meaningfully reduce LDL cholesterol in adult patients unable or unwilling to take statin drugs.
