Mediterranean Diet Reduces Cardiovascular Risk

Today’s post has nothing directly to do with mental health issues. However, since the cardiovascular fitness significantly affects the risk for psychiatric disorders – especially dementia -, I would like to report today on a very interesting study published in the New England Journal of Medicine on April 4, 2013, in which the influence of a Mediterranean diet on cardiovascular risk was studied (Estruch et al., N Engl J Med 2013, 368: 1279-1290). In a randomized multicenter study conducted in Spain 7447 subjects (57% women) who did not suffer from cardiovascular illness at inclusion in the study were observed for a median of 4.8 years. About one-third of the subjects fed themselves with a Mediterranean diet, which had been enriched by olive oil (extra-virgin), another third lived on a Mediterranean diet supplemented with nuts. The control group was given the instruction to eat a low fat diet. The groups who supplemented their Mediterranean diet with olive oil or nuts got a free liter of olive oil a week or 30 grams of nuts a day (15 walnuts, 7.5 g hazelnuts, almonds 7.5  g), respectively. The control group received small non-food gifts. Caloric intake was not restricted, and physical activity was not particularly recommended. The primary endpoint was a composite of heart attack, stroke or death from a cardiovascular event. Secondary endpoints were heart attack, stroke, death from a cardiovascular event or death from any cause.

Participants were regularly trained individually and in group sessions to adhere to the following diets:

Mediterranean Diet:

Recommended:

  • Olive Oil                                                           ≥ 4 Tablespoons/Day
  • Tree Nuts and Peanuts                                    ≥ 3 Servings/Week
  • Fresh Fruits                                                     ≥ 3 Servings/Day
  • Vegetables                                                      ≥ 2 Servings/Day
  • Fish (esp. fatty fish), Seafood                           ≥ 3 Servings/Week
  • Legumes                                                         ≥ 3 Servings/Week
  • Sofrito                                                              ≥ 2 Servings/Week
  • White Meat                                                      Instaed of Red Meat
  • Wine with Meals (optional)                                ≥ 7 Glasses/Week

Discouraged:

  • Soda Drinks                                                     < 1 Drink/Day
  • Bakery Goods, Sweets, Pastries                      < 3 Portionen/Woche
  • Spread Fats                                                     < 1 Serving/Day
  • Res and Processed Meats                               < 1 Serving/Day

LowFat Diet (Control Group):

Recommended:

  • Low-Fat Dairy Products                                  ≥ 3 Servings/Day
  • Bread, Potatoes, Pasta, Rice                          ≥ 3 Servings/Day
  • Fresh Fruits                                                     ≥ 3 Servings/Day
  • Vegetables                                                      ≥ 2 Servings/Week
  • Lean Fish, Seafood                                         ≥ 3 Servings/Week

Discouraged:

  • Vegetable Oils (incl. Olive Oil)                          ≤ 2 Tablespoons/Day
  • Bakery Goods, Sweets, Pastries                    ≤ 1 Serving/Week
  • Nuts, Fried Snacks                                         ≤ 1 Serving/Week
  • Res and Processed Fatty Meats                     ≤ 1 Serving/Week
  • Visible Fat in Meats and Soups                       Always Remove
  • Fatty Fish, Seafood Canned in Oil                   ≤ 1 Serving/Week
  • Spread Fats                                                    ≤ 1 Serving/Week
  • Sofrito                                                            ≤ 2 Servings/Week

The subjects in the group who supplemented their diet with olive oil were asked to use only the provided oil (at least 50 g/day, equivalent to about four tablespoons), as this is rich in polyphenols. The usual refined oil is low in polyphenols. Sufrito is a sauce of tomatoes and onions, often with garlic and other spices, which is slowly simmered with olive oil.

At baseline the participants were on average 67 years old (range 55 – 80). 97% were white with European origin. Approximately 14% of participants in all groups were current smokers, 24-26% were former smokers. They were on average overweight, the mean BMI was 30. Only 7 or 8% had a BMI at baseline below 25. Vascular risk factors were present to a significant degree: 82-84% had hypertension, 47-50% had type II diabetes and 72-73% had dyslipidemia.

The subjects were observed for a total of between 9763 years (control group) and 11,852 years (olive oil). 11.2 events per 1000 person-years occurred in the control group, but only 8.1 (olive oil) and 8.0 (nuts) events in the groups fed with a Mediterranean diet. Thus, in both groups on a Mediterranean diet occurred statistically significantly less events than in the control group (olive oil vs. control: p = 0.009; nuts vs. control. P = 0.02.). Regarding the secondary endpoints, the Mediterranean diet significantly reduced the number of strokes (5.9 events per 1000 person-years in the control group; 4.1 events in the olive oil group, P = 0.03; 3.1 events in the nuts group, p = 0.003).

Overall, the study shows that a Mediterranean diet, even if it starts relatively late, reduces cardiovascular risk by 30% compared with a low-fat diet. A PDF of the paper can be obtained from me. I will discuss the cognitive effects of the Mediterranean diet, which was also examined by the authors, in a separate post in the future.

 

This post is also available in: German

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