Virgin olive oil supplementation and long-term cognition: the PREDIMED-NAVARRA randomized, trial.
Study Goal
The researchers aimed to determine whether a Mediterranean diet supplemented with mixed nuts improves cognitive performance compared to a low-fat control diet.
Results Summary
The study found no significant differences in cognitive performance between participants on the MedDiet+Nuts and the control group, unlike the MedDiet+EVOO group, which showed better cognitive outcomes.
Population
285 participants at high vascular risk (44.8% men, average age 74.1±5.7 years).
Effective Dosage
30 g/day of mixed nuts.
Duration
6.5 years.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Mediterranean diet supplemented with extra-virgin olive oil (MedDiet+EVOO) | increase | cognitive performance | participants at high vascular risk | - | Better post-trial cognitive performance versus control | #1 |
Mediterranean diet supplemented with extra-virgin olive oil (MedDiet+EVOO) | increase | fluency and memory tasks | participants at high vascular risk | - | significantly better performance | #2 |
Mediterranean diet supplemented with extra-virgin olive oil (MedDiet+EVOO) | decrease | mild cognitive impairment (MCI) | participants at high vascular risk | OR=0.34 95% CI: 0.12-0.97 | showed lower MCI | #3 |
Mediterranean diet supplemented with mixed nuts (MedDiet+Nuts) | no change | cognitive performance | participants at high vascular risk | - | did not differ from controls | #4 |
EVOO-rich Mediterranean diet | increase | cognitive function | participants at high vascular risk | - | resulted in a better cognitive function | #5 |
EVOO-rich Mediterranean diet | no change | most cognitive domains | participants at high vascular risk | - | non-significant differences were found | #6 |
EVOO-rich Mediterranean diet | decrease | mild cognitive impairment (MCI) | participants at high vascular risk | - | had less MCI | #7 |
OBJECTIVE: To assess the effect on cognition of a controlled intervention testing Mediterranean diets (MedDiet). DESIGN: Randomized trial after 6.5 years of nutritional intervention. SETTING: Eight primary care centers affiliated to the University of Navarra. PARTICIPANTS: A random subsample of 285 participants (95 randomly allocated to each of 3 groups) of the PREDIMED-NAVARRA trial. All of them were at high vascular risk (44.8% men, 74.1±5.7 years at cognitive evaluation). INTERVENTIONS: Nutritional intervention comparing two MedDiets (supplemented with extra-virgin olive oil [EVOO] or mixed nuts) versus a low-fat control diet. Participants received intensive education to increase adherence to the intended intervention. Participants allocated to the MedDiet groups received EVOO (1 l/week) or 30 g/day of mixed nuts. Dietary habits were evaluated using a validated 137-item food frequency questionnaire (FFQ). Additionally, adherence to MedDiet was appraised using a 14-item questionnaire both at baseline and yearly thereafter. MEASUREMENTS: Cognitive performance as a main outcome and cognitive status (normal, mild cognitive impairment [MCI] or dementia) as a secondary outcome were evaluated by two neurologists blinded to group assignment after 6.5 years of nutritional intervention. RESULTS: Better post-trial cognitive performance versus control in all cognitive domains and significantly better performance across fluency and memory tasks were observed for participants allocated to the MedDiet+EVOO group. After adjustment for sex, age, education, apolipoprotein E genotype, family history of cognitive impairment/dementia, smoking, physical activity, body mass index, hypertension, dyslipidaemia, diabetes, alcohol and total energy intake, this group also showed lower MCI (OR=0.34 95% CI: 0.12-0.97) compared with control group. Participants assigned to MedDiet+Nuts group did not differ from controls. CONCLUSION: A long-term intervention with an EVOO-rich MedDiet resulted in a better cognitive function in comparison with a control diet. However, non-significant differences were found for most cognitive domains. Participants allocated to an EVOO-rich MedDiet had less MCI than controls.