Mediterranean diets and metabolic syndrome status in the PREDIMED randomized trial.
Study Goal
The researchers aimed to evaluate the long-term effect of Mediterranean diets ad libitum on the incidence or reversion of metabolic syndrome in individuals at high risk for cardiovascular disease.
Results Summary
The study found that Mediterranean diets supplemented with extra-virgin olive oil or nuts did not reduce the incidence of metabolic syndrome but significantly increased the likelihood of reversion. Participants on these diets showed improvements in central obesity and fasting glucose levels.
Population
Men and women aged 55-80 years at high risk for cardiovascular disease.
Effective Dosage
Not specified (ad libitum Mediterranean diet supplemented with extra-virgin olive oil or nuts).
Duration
4.8 years
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Mediterranean diet supplemented with extra-virgin olive oil | no change | risk of developing metabolic syndrome | men and women (age 55-80 yr) at high risk for cardiovascular disease | HR 1.10, 95% CI 0.94-1.30, p = 0.231 | did not differ | #1 |
Mediterranean diet supplemented with nuts | no change | risk of developing metabolic syndrome | men and women (age 55-80 yr) at high risk for cardiovascular disease | HR 1.08, 95% CI 0.92-1.27, p = 0.3 | did not differ | #2 |
Mediterranean diet supplemented with extra-virgin olive oil | increase | reversion of metabolic syndrome | men and women (age 55-80 yr) at high risk for cardiovascular disease | HR 1.35, 95% CI 1.15-1.58, p < 0.001 | more likely to undergo | #3 |
Mediterranean diet supplemented with nuts | increase | reversion of metabolic syndrome | men and women (age 55-80 yr) at high risk for cardiovascular disease | HR 1.28, 95% CI 1.08-1.51, p < 0.001 | more likely to undergo | #4 |
Mediterranean diet supplemented with extra-virgin olive oil | decrease | central obesity | participants in the group receiving olive oil supplementation | p = 0.02 | significant decreases | #5 |
Mediterranean diet supplemented with extra-virgin olive oil | decrease | high fasting glucose | participants in the group receiving olive oil supplementation | p = 0.02 | significant decreases | #6 |
Mediterranean diet supplemented with nuts | decrease | central obesity | participants in the group supplemented with nuts | - | significant decrease | #7 |
BACKGROUND: Little evidence exists on the effect of an energy-unrestricted healthy diet on metabolic syndrome. We evaluated the long-term effect of Mediterranean diets ad libitum on the incidence or reversion of metabolic syndrome. METHODS: We performed a secondary analysis of the PREDIMED trial--a multicentre, randomized trial done between October 2003 and December 2010 that involved men and women (age 55-80 yr) at high risk for cardiovascular disease. Participants were randomly assigned to 1 of 3 dietary interventions: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with nuts or advice on following a low-fat diet (the control group). The interventions did not include increased physical activity or weight loss as a goal. We analyzed available data from 5801 participants. We determined the effect of diet on incidence and reversion of metabolic syndrome using Cox regression analysis to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: Over 4.8 years of follow-up, metabolic syndrome developed in 960 (50.0%) of the 1919 participants who did not have the condition at baseline. The risk of developing metabolic syndrome did not differ between participants assigned to the control diet and those assigned to either of the Mediterranean diets (control v. olive oil HR 1.10, 95% CI 0.94-1.30, p = 0.231; control v. nuts HR 1.08, 95% CI 0.92-1.27, p = 0.3). Reversion occurred in 958 (28.2%) of the 3392 participants who had metabolic syndrome at baseline. Compared with the control group, participants on either Mediterranean diet were more likely to undergo reversion (control v. olive oil HR 1.35, 95% CI 1.15-1.58, p < 0.001; control v. nuts HR 1.28, 95% CI 1.08-1.51, p < 0.001). Participants in the group receiving olive oil supplementation showed significant decreases in both central obesity and high fasting glucose (p = 0.02); participants in the group supplemented with nuts showed a significant decrease in central obesity. INTERPRETATION: A Mediterranean diet supplemented with either extra virgin olive oil or nuts is not associated with the onset of metabolic syndrome, but such diets are more likely to cause reversion of the condition. An energy-unrestricted Mediterranean diet may be useful in reducing the risks of central obesity and hyperglycemia in people at high risk of cardiovascular disease. TRIAL REGISTRATION: ClinicalTrials.gov, no. ISRCTN35739639.