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Scientifically proven diets that work

Heart-healthy diets emphasize fruits and vege-tables as a major source of daily calories.

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Substantial research proves the Mediterranean and DASH eating plans offer important health benefits for men.

Many diets promise weight loss, but if your priority is to prevent major chronic illnesses, the choices narrow. Only a handful are backed by extensive scientific evidence for health benefits of primary interest to men, like controlling blood pressure and preventing heart attacks and strokes.

Two such eating plans are the Dietary Approaches to Stop Hypertension (DASH) diet and the Mediterranean diet. Both emphasize eating plant foods and healthy fats to reduce the risk of cardiovascular disease. Evidence for wider benefits is accumulating, too—like preserving memory.

“There are so many other diets out there that may work for an individual for weight loss,” says registered dietitian Kathy -McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women’s Hospital. “But these are two for preventing chronic disease. That’s why these specific diets keep floating to the top.”

What is a Mediterranean diet?

Health researchers noticed that cultures in the Mediterranean region had lower rates of cardiovascular disease and determined that what those people eat (and don’t eat) had something to do with it. Here are the general features of a Mediterranean dietary pattern:

  • Plant foods as the main source of daily calories. These include fruits, vegetables, whole grains, nuts, and legumes (like beans, peas, and lentils), with a preference for foods that are fresh and minimally processed to preserve nutrients.

    Olive oil as the main source of fat calories. Some research suggests that extra-virgin olive oil may contain beneficial substances that other oils lose in processing steps.

  • Low to moderate amounts of cheese and yogurt with meals.

  • Minimal amounts of red meat, with moderate amounts of fish and poultry as the preferred sources of animal protein.

  • Small amounts of sweets, eaten occasionally; fresh fruit with meals instead of desserts.

  • For those who drink alcohol, wine consumed in low to moderate amounts, usually with meals.

What the science says: The largest test of the Mediterranean diet to date was PREDI-MED, a randomized clinical trial in Spain involving nearly 7,500 people 55 to 80 years old. Participants were told to eat either a reduced-fat diet or a Mediterranean diet supple-mented with nuts or extra-virgin
-olive oil. After about five years, people who ate the supplemented diet were up to 30% less likely to have heart -attacks and strokes or die from heart-related causes.

It’s not only about food, because exercise patterns and other factors probably also play a role. “The Mediterranean diet is really more of a lifestyle,” McManus says.

What is DASH?

The DASH diet was specifically designed to lower blood pressure. This diet has some important things in common with a Mediterranean eating style, such as generous amounts of fruits, vegetables, and grains, but imposes stricter limits on fat and sodium. Here are DASH’s major features:

  • most daily calories from fruits, vegetables, and grains

  • reduced total and saturated fat

  • moderate amounts of fat-free or low-fat milk and milk products

  • low in red meat, sweets, added sugars, and beverages containing sugar

  • reduced sodium for greatest effect on blood pressure

  • rich in potassium, magnesium, calcium, and fiber.

What the science says: In the 1990s, two major clinical trials showed that the DASH diet lowers blood pressure. In addition, it is considered a generally nutritious and heart-healthy diet.

DASH or Mediterranean?

If you have high blood pressure, the DASH diet is an obvious choice. But that means it’s less flexible. “It was tested in a randomized clinical trial, so you can’t steer too far away from it to get the effect on blood pressure,” McManus says.

For example, the DASH diet sets specific targets for sodium and fat. People who want to get the most benefit from the DASH diet would have to limit their sodium intake to 1,500 milligrams (mg) per day—a goal that is difficult at best. For most other adults, the limit is 2,300 mg.

In contrast, the Mediterranean style of eating imposes no specific limits on sodium, although most physicians encourage their patients—especially those with high blood pressure—to reduce the amount of sodium they take in.

The diets also differ in terms of fat intake. The DASH diet caps fat intake at 27% of total calories, with saturated fat being no more than 6%. In short, DASH is a reduced-fat diet.

The Mediterranean diet is not a reduced-fat diet. Participants got about 40% of their calories as fat—primarily healthy mono- and polyunsaturated fats from nuts or olive oil.

What’s the bottom line? A Mediterranean-style diet is, like DASH, a good place to start for heart health. It’s also flexible enough to accommodate different food preferences while maintaining a healthy balance of nutrients.

But if your top concern is blood pressure, consider giving DASH a try—and be prepared for some strict limits on
sodium and fat intake. It’s easy to obtain detailed information about the DASH diet, such as suggested daily meal portions and sample menus and recipes. You can find that information online at www.health.harvard.edu/dash.

Healthy diet swaps

It’s wise to transition gradually to a new style of eating. Here are some suggestions for ways to adopt a healthier eating style consistent with either a DASH or Mediterranean diet:

  • Sauté vegetables, poultry, or fish in olive oil, not butter.

  • Toss a small handful of nuts, diced fruit, or cooked and chilled whole grain into garden salads.

  • Drizzle extra-virgin olive oil and lemon juice over salads.

  • Stir a handful or two of green leafy vegetables like kale or Swiss chard into pasta sauces.

  • Mix white rice with bulgur wheat or quinoa.

  • Snack on carrot, celery, or sliced pepper sticks instead of pretzels or chips.

  • Replace half of your refined semolina pasta with whole-grain pasta.

  • Use whole-wheat tortillas to make roll-up sandwiches.

  • Try hummus spread instead of mayonnaise on your sandwich.

  • Eat fresh sliced fruit with meals and save sweet desserts as a restaurant treat.

Posted by: Dr.Health

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