PREDIMED Study – Traditional Mediterranean Diet (TMD)
The PREDIMED Study evaluated the Traditional Mediterranean Diet (TMD) for the prevention of Cardiovascular Disease. The Traditional Mediterranean Diet has been a favorite for health advocates for years. Multiple observational and secondary prevention trials showed improvement in risk for Cardiovascular Disease so the authors of the PREDIMED Study conducted a randomized trial to confirm (or debunk) these observations.
The PREDIMED Study was conducted in multiple locations (centers) in Spain. The participants were considered to be at ‘High cardiovascular disease risk’ but had no cardiovascular disease at enrollment. High risk of cardiovascular disease meant that participants were either Type 2 diabetic or at least 3 of the following: smoking, hypertension, elevated LDL, low HDL, overweight/obese, or family history of premature cardiovascular disease.
3 Diets:
- Mediterranean diet supplemented with extra-virgin olive oil (EVOO)
- Mediterranean diet supplemented with mixed nuts (walnuts, almonds, and hazelnuts)
- Control diet – they were advised to reduce dietary fat
All participants received educational sessions (individual and group) every quarter. Depending on the group, they were given free extra-virgin olive oil (~1 liter per week), mixed nuts (30 grams per day), or small nonfood gifts. They did not control or adjust caloric intake and there was no promotion of exercise or physical activity.
Mediterranean Diet
Recommended Foods
- Olive Oil: >4 tablespoons per day. The amount of olive oil includes oil used for cooking and salads and oil consumed in meals eaten outside the home. In the Mediterranean Diet Olive Oil group, the goal was to consume 50 grams (approximately 4 tablespoons) or more per day of the polyphenol-rich olive oil supplied to them as opposed to the ordinary refined variety, which is low in polyphenols.
- Tree nuts and peanuts: > 3 servings per week
- Fresh fruits: > 3 servings per day
- Vegetables: > 2 servings per day
- Fish (especially fatty fish) & Seafood: > 3 servings per week
- Legumes: > 3 servings per week
- Sofrito: > 2 servings per week. Sofrito is a sauce made with tomato and onion, often including garlic and aromatic herbs, and slowly simmered with olive oil.
- White meat: instead of red meat
- Wine with meals (optional, only for those already drinking alcohol): > 7 glasses per week
Discouraged Foods
- Sodas (soft drinks): < 1 per day
- Commercial baked good, sweets, & pastries: <3 servings per day
- Spread fats: <1 serving per day
- Red and processed meats: < 1 serving per day
Control Diet (low fat)
Recommended Foods
- Low-fat dairy products: > 3 servings per day
- Bread, potatoes, pasta, rice: > 3 servings per day
- Fresh fruits: > 3 servings per day
- Vegetables: > 2 servings per day
- Lean fish & seafood: > 3 servings per week
Discouraged Foods
- Vegetable oils (including olive oil): < 2 tablespoons per day
- Commercial baked good, sweets, & pastries: < 1 serving per week
- Spread fats: <1 serving per week
- Red and processed meats: < 1 serving per week
- Nuts and fried snacks: < serving per week
- Visible fat in meats and soups: always remove
- Fatty fish, seafood canned in oil: < 1 serving per week
- Sofrito: < 2 servings per week
Compliance
Compliance with all of the diet groups was good. Biomarkers (hydroxytyrosol for olive oil group & ALA level for mixed nuts group) were measured to confirm compliance.
Participants were followed for 4.8 years. 209 participants (2.8%) opted to not attend subsequent visits. Dropouts were higher in the Control Diet (11.3%) than in the Mediterranean Diet (4.9%).
Increased benefit was noted in the group with dyslipidemia and hypertension in regards to the primary end-point.
Conclusions:
The primary end points (for what they were looking to see if the diet helped) were major cardiovascular disease events (myocardial infarction, stroke, or death from cardiovascular disease causes). The study was conducted for 4.8 years. The study was funded by the Spanish Government (Instituto de Salud Carlos III and others).
There were a total of 7447 participants, 55-80 years of age. The primary end-point (myocardial infarction, stroke, or death from cardiovascular disease causes) occurred in a total of 288 of the participants.
- Mediterranean diet with extra-virgin olive oil – 96 events, 30% reduced risk (hazard ratio 0.70)
- Mediterranean diet with mixed nuts – 83 events, 28% reduced risk (hazard ratio 0.72)
- Control diet – 109 events
The author’s conclusion: “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.”
