Is the so-called “Mediterranean” diet – and ones like it – really good for heart and overall health?
The evidence is mostly circumstantial … but highly credible, judging by strong lab and clinical data … and keeps mounting.
As a team of evidence-reviewers wrote three years ago, the diet offers “… significant and consistent protection … in relation to the occurrence of major chronic degenerative diseases.” (Sofi F et al. 2010)
Still, many scientists withheld final judgment pending publication of a large, rigorously designed and conducted trial.
Now, a high-quality trial confirms indications that the Mediterranean diet is very heart-healthy, indeed.
The results – published in The New England Journal of Medicine – show that eating a Mediterranean diet for five years slashed by 30 percent the risk of suffering a cardiovascular death, heart attack, or stroke.
Med diet passes tough clinical test ... with flying colors
The study was led by Ramon Estruch, M.D., of the University of Barcelona, as part of the five-year PREDIMED trial (Estruch R et al. 2013).
A total of 7,447 people with major cardiovascular risk factors – e.g., overweight, smoking, hypertension, diabetes, metabolic syndrome – participated.
Each of three groups agreed to follow an assigned diet for five years:
- Low-fat diet (animal and plant foods)
Mediterranean diet supplemented with extra-virgin olive oil
Mediterranean diet supplemented with nuts (walnuts, almonds, hazelnuts)
The “Mediterranean diet” was defined very specifically:
Fruits – 3 servings daily
Vegetables – 2 servings daily
Fish – 3 or more servings weekly; preferably fatty fish
Beans – 3 or more servings weekly
Sofrito – 2 or more servings weekly*
Poultry (in place of habitual red meat)
Extra virgin olive oil (EVOO) – 4 tbsp daily or Nuts – 3 servings weekly (walnuts, almonds, and hazelnuts)
Glass of wine at dinner (optional, and only if previously habitual)
*Traditional Mediterranean sauce of tomato, onion, garlic, EVOO, and herbs.
The participants who followed either of the two Mediterranean diets received free extra virgin olive oil (one liter weekly) and nuts (30 grams per day; 15 grams of walnuts, 7.5 grams of almonds and 7.5 grams of hazelnuts).
Both Mediterranean diet groups were asked to limit dairy foods, red meats, processed meats and avoid soda and commercial baked goods (cookies, cakes, and pastries).
All of the volunteers attended group diet training sessions and got shopping lists, menus and recipes adapted to each type of diet and each season of the year. And each one was visited by a dietitian every three months.
To test compliance with the Mediterranean diets, the researchers measured urine levels of two things:
- Hydroxytyrosol, a potent, artery-loving antioxidant unique to olive oil.
- ALA, the plant-form omega-3 fatty acid found in walnuts and dark, leafy greens.
After five years, the participants who followed either of the two Mediterranean diets showed a substantial reduction in the risk of suffering a cardiovascular death, a myocardial infarction or a stroke.
The results prove that, for cardiovascular health, a diet high in fish, whole plant foods, and ample portions of healthful fats beats a low-fat diet … hands down.
Low-fat vs. Mediterranean: No contest
To be sure, low-fat diets can cut blood cholesterol and fat levels drastically – if not always healthfully.
And low fat diest are near-impossible for patients to keep up … as shown by the new study.
While the Mediterranean diet groups stuck with their eating plans, the low-fat diet group did not lower their fat intake very much over the course of the trial, proving that they could not follow their assigned plan.
To a large extent, the trial ended up comparing a semi-American-style diet high in processed and refined foods to a diet featuring healthful whole foods and not too much refined carbohydrate (bread, pasta).
While the diet slashed the risk of adverse heart disease events sharply for people at high risk, more research is needed to define its benefits for people at low risk.
Dr. Estruch expects it would also help people at low risk, and suggested starting a healthy diet in childhood.
Estruch R, Ros E, Salas-Salvadó J, Covas MI, D Pharm, Corella D, Arós F, Gómez-Gracia E, Ruiz-Gutiérrez V, Fiol M, Lapetra J, Lamuela-Raventos RM, Serra-Majem L, Pintó X, Basora J, Muñoz MA, Sorlí JV, Martínez JA, Martínez-González MA; the PREDIMED Study Investigators. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet. N Engl J Med. 2013 Feb 25. [Epub ahead of print]
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