Chapter 21
Lifestyle+ — 12
Compared with eating few or no nuts and seeds a day, eating just a handful is associated with a 20 percent lower risk of cardiovascular disease, as seen in more than forty studies. Nut consumption, despite high caloric density, has also been linked to lower risks of obesity and weight gain.
The whole package of all these goodies is known as the Mediterranean diet (see below). Happily, this diet has been assessed by multiple randomized trials, unusual in the field of nutrition science. Data from over 12.8 million participants in randomized trials and observational studies provide robust support for benefit of the Mediterranean diet for its association with a reduction of death from any cause—cardiovascular diseases, coronary heart disease, myocardial infarction, cancer, neurodegenerative diseases, and diabetes. That’s a compelling list of outcomes!
Mediterranean Diet
Goal
RECOMMENDED
Olive oil
≥4 tbsp/day
Tree nuts and peanuts
≥3 servings/wk
Fresh fruits
≥3 servings/day
Vegetables
≥2 servings/day
Fish (especially fatty fish), seafood
≥3 servings/wk
Legumes
≥3 servings/wk
Sofrito
≥2 servings/wk
White meat
Instead of red meat
Wine with meals (optionally, only for habitual drinkers)
≤7 glasses/wk
DISCOURAGED
Soda drink
<1 drink/day
Commercial bakery goods, sweets, and pastries
<2 servings/wk
Spread fats
<1 serving/day
Red and processed meats
<1 serving/day
More than a decade ago, a trial of 7,477 participants, deemed at increased risk for heart disease, were randomly assigned to either a Mediterranean diet supplemented with extra-virgin olive oil or a Mediterranean diet with supplemented nuts, or a control diet of reduced dietary fat. A five-year follow-up showed a 30 percent lower risk of cardiovascular death, heart attack, or stroke with the two Mediterranean diets versus the control diet. The initial trial report had to be retracted and republished because of errors in random assignment and some protocol deviations, but with no substantive change in the results. That is one of the largest randomized trials in nutrition history, and it points toward the primary prevention benefit of the Mediterranean diet in people considered at high risk.
What about secondary prevention, people who already have manifested cardiovascular disease? Over thirty years ago, a trial known as the Lyon Heart Study randomly assigned about six hundred heart attack survivors to a Mediterranean diet or control and showed a 70 percent reduction of mortality during a five-year follow-up. In a more recent randomized trial conducted in people with established heart disease, the Mediterranean diet was compared with a low-fat diet in one thousand participants (83 percent were men) with follow-up of up to seven years. Cardiovascular events, such as heart attacks, strokes, or needs for bypass surgery, were reduced by 26 percent with the Mediterranean diet, and among men by 33 percent. For more than twenty-five thousand women followed for five years, a higher adherence to a Mediterranean diet was associated with 23 percent reduction of all-cause mortality.