Archive

Research Area: Cardiovascular Health

Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts.

Estruch, R., E. Ros, J. Salas-Salvadó, M.-I. Covas, D. Corella, F. Arós, E. Gómez-Gracia, V. Ruiz-Gutiérrez, M. Fiol, J. Lapetra, R.M. Lamuela-Raventos, L. Serra-Majem, X. Pintó, J. Basora, M.A. Muñoz, J.V. Sorlí, J.A. Martínez, M. Fitó, A. Gea, M.A. Hernán, M.A. Martínez-González, PREDIMED Study Investigators, 2018. Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts. N Engl J Med.  378(25):e34. doi: 10.1056/NEJMoa1800389. Epub 2018 Jun 13.

Background: Observational cohort studies and a secondary prevention trial have shown inverse associations between adherence to the Mediterranean diet and cardiovascular risk. Methods: In a multicenter trial in Spain, we assigned 7447 participants (55 to 80 years of age, 57% women) who were at high cardiovascular risk, but with no cardiovascular disease at enrollment, to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a control diet (advice to reduce dietary fat). Participants received quarterly educational sessions and, depending on group assignment, free provision of extra-virgin olive oil, mixed nuts, or small nonfood gifts. The primary end point was a major cardiovascular event (myocardial infarction, stroke, or death from cardiovascular causes). After a median follow-up of 4.8 years, the trial was stopped on the basis of a prespecified interim analysis. In 2013, we reported the results for the primary end point in the Journal. We subsequently identified protocol deviations, including enrollment of household members without randomization, assignment to a study group without randomization of some participants at 1 of 11 study sites, and apparent inconsistent use of randomization tables at another site. We have withdrawn our previously published report and now report revised effect estimates based on analyses that do not rely exclusively on the assumption that all the participants were randomly assigned. Results: A primary end-point event occurred in 288 participants; there were 96 events in the group assigned to a Mediterranean diet with extra-virgin olive oil (3.8%), 83 in the group assigned to a Mediterranean diet with nuts (3.4%), and 109 in the control group (4.4%). In the intention-to-treat analysis including all the participants and adjusting for baseline characteristics and propensity scores, the hazard ratio was 0.69 (95% confidence interval [CI], 0.53 to 0.91) for a Mediterranean diet with extra-virgin olive oil and 0.72 (95% CI, 0.54 to 0.95) for a Mediterranean diet with nuts, as compared with the control diet. Results were similar after the omission of 1588 participants whose study-group assignments were known or suspected to have departed from the protocol. Conclusions: In this study involving persons at high cardiovascular risk, the incidence of major cardiovascular events was lower among those assigned to a Mediterranean diet supplemented with extra-virgin olive oil or nuts than among those assigned to a reduced-fat diet. (Funded by Instituto de Salud Carlos III, Spanish Ministry of Health, and others; Current Controlled Trials number, ISRCTN35739639 .).

The effects of daily intake timing of almond on the body composition and blood lipid profile of healthy adults.

Liu, Y., H.-J. Hwang, H. Ryu, Y.-S. Lee, H.-S. Kim, H. Park, 2017. The effects of daily intake timing of almond on the body composition and blood lipid profile of healthy adults. Nutrition Research and Practice. 11(6):479-486.

BACKGROUND/OBJECTIVES: Timing of almond intake during a day may result differently in the perspectives of body composition and changes of lipid profile. The current study was conducted to compare the effects of daily almond intake as a preload versus as a snack on body composition, blood lipid profile, and oxidative and inflammation indicators among young Korean adults aged 20-39 years old. SUBJECTS/METHODS: Participants were randomly assigned to one of three groups: a pre-meal almond group (PM), a snack almond group (SN) in which participants were instructed to consume 56 g of almonds either as a preload before meals or as a snack between meals, respectively, and a control group (CL) in which participants were provided high-carbohydrate iso-caloric control food. Measurements were performed at baseline, weeks 8 and 16. RESULTS: A total of 169 (M 77 / F 92) out of the 227 participants completed the study between June 2014 and June 2015 (n=58 for PM; 55 for SN; and 56 for CL). A significant decrease in body fat mass was observed in the PM group at both weeks 8 and 16 compared with the CL. There were significant intervention effects on changes of body fat mass (P=0.025), body fat percentages (P=0.019), and visceral fat levels (P<0.001). Consuming almonds as a daily snack reduced the levels of total cholesterol (P=0.043) and low-density lipoprotein (LDL) cholesterol (P=0.011) without changing high-density lipoprotein (HDL) cholesterol compared with the CL. CONCLUSION: Almond consumption as a preload modified body fat percentages, whereas snacking on almonds between meals improved blood lipid profiles.

Effect of nut consumption on vascular endothelial function: A systematic review and meta-analysis of randomized controlled trials.

Xiao, Y., W. Huang, C. Peng, J. Zhang, C. Wong, J.H. Kim, E.-K. Yeoh, 2017. Effect of nut consumption on vascular endothelial function: A systematic review and meta-analysis of randomized controlled trials. Clinical Nutrition. http://dx.doi.org/10.1016/j.clnu.2017.04.011

Objective: Nut consumption has consistently been found to be associated with a reduced risk of cardiovascular diseases (CVD) and mortality in prospective studies. However, its effect on endothelial function, a prognostic marker of CVD, is still controversial in clinical trials. This meta-analysis of randomized controlled trials (RCTs) aimed to quantitatively assess the effect of nuts on vascular endothelial function. Methods: Major electronic databases were searched for published RCTs that reported the effect of nuts on flow mediated dilation (FMD) as a measurement of endothelial function in the adult population (age eighteen years or over). We calculated the pooled estimates of weighted mean differences (WMDs) and their 95% confidence intervals (CIs) by using random-effects models. Results: A total of nine papers (10 trials) involving 374 participants were included. The pooled estimates found that nut consumption significantly improved FMD (WMD: 0.41%; 95% CI: 0.18%, 0.63%; P = 0.001). Moderate and marginally significant heterogeneity was observed among the studies (I2 = 39.5%, P = 0.094). Subgroup analyses indicated that walnuts significantly improved FMD (WMD: 0.39%; 95% CI: 0.16%, 0.63%; P = 0.001). In addition, nut consumption had a significant effect on FMD in the trials with study duration <18 weeks, nut dose <67 g/d, or subjects with baseline FMD ≥8.6%. Conclusions: Nut consumption significantly improved endothelial function. However, the beneficial effect was limited to walnuts. More studies examining the effect of other nuts on endothelial function are needed in the future.

Inclusion of almonds in a cholesterol-lowering diet improves plasma HDL subspecies and cholesterol efflux to serum in normal-weight individuals with elevated LDL cholesterol.

Berryman, C.E, J.A. Fleming, P.M. Kris-Etherton, 2017. Inclusion of almonds in a cholesterol-lowering diet improves plasma HDL subspecies and cholesterol efflux to serum in normal-weight individuals with elevated LDL cholesterol. J. Nutr. 147(8). doi: 10.3945/jn.116.245126.

Background: Almonds may increase circulating HDL cholesterol when substituted for a high-carbohydrate snack in an isocaloric diet, yet little is known about the effects on HDL biology and function. Objective: The objective was to determine whether incorporating 43 g almonds/d in a cholesterol-lowering diet would improve HDL subspecies and function, which were secondary study outcomes. Methods: In a randomized, 2-period, crossover, controlled-feeding study, a diet with 43 g almonds/d (percentage of total energy: 51% carbohydrate, 16% protein, and 32% total and 8% saturated fat) was compared with a similar diet with an isocaloric muffin substitution (58% carbohydrate, 15% protein, and 26% total and 8% saturated fat) in men and women with elevated LDL cholesterol. Plasma HDL subspecies and cholesterol efflux from J774 macrophages to human serum were measured at baseline and after each diet period. Diet effects were examined in all participants (n = 48) and in normal weight (body mass index: <25; n = 14) and overweight or obese (≥25; n = 34) participants by using linear mixed models. Results: The almond diet, compared with the control diet, increased α-1 HDL [mean ± SEM: 26.7 ± 1.5 compared with 24.3 ± 1.3 mg apolipoprotein A-I (apoA-I)/dL; P = 0.001]. In normal-weight participants, the almond diet, relative to the control diet, increased a-1 HDL (33.7 6 3.2 compared with 28.4 ± 2.6 mg apoA-I/dL), the α-1 to pre–β-1 ratio [geometric mean (95%CI): 4.3 (3.3, 5.7) compared with 3.1 (2.4,4.0)], and non–ATP-binding cassette transporter A1 cholesterol efflux (8.3% ± 0.4% compared with 7.8% ± 0.3%) and decreased pre–β-2 (3.8 ± 0.4 compared with 4.6 ± 0.4 mg apoA-I/dL) and α-3 (23.5 ± 0.9 compared with 26.9 ± 1.1 mg apoA-I/dL) HDL (P < 0.05). No diet effects were observed in the overweight or obese group. Conclusions: Substituting almonds for a carbohydrate-rich snack within a lower-saturated-fat diet may be a simple strategy to maintain a favorable circulating HDL subpopulation distribution and improve cholesterol efflux in normal-weight individuals with elevated LDL cholesterol.