Mediterranean diet: A heart-healthy eating plan that may also benefit your brain

You may know that a Mediterranean diet — rich in fruits, vegetables, olive oil, legumes, whole grains and fish — offers many heart-healthy benefits. But a Mediterranean diet may also benefit your brain.

Studies show people who closely follow a Mediterranean diet are less likely to have Alzheimer's disease than people who don't follow the diet.

Research suggests a Mediterranean diet may:

• Slow cognitive decline in older adults
• Reduce the risk of mild cognitive impairment (MCI) — a transitional stage between the cognitive decline of normal aging and the more-serious memory problems caused by dementia or Alzheimer's disease
• Reduce the risk of MCI progressing into Alzheimer's disease

It's unclear which parts of the Mediterranean diet might protect brain function.

Researchers speculate that making healthy food choices may improve cholesterol and blood sugar levels and overall blood vessel health, which may in turn reduce the risk of MCI or Alzheimer's disease.

Another theory suggests that following a Mediterranean diet may help prevent brain tissue loss associated with Alzheimer's.

But for now it's difficult to say what exactly explains the relationship between following a Mediterranean diet and reducing the risk of Alzheimer's disease. Some research shows that individuals with moderate seafood consumption had fewer Alzheimer's-related changes in their brains among people carrying the apolipoprotein E (APOE e4) gene, which is thought to increase Alzheimer's risk.

But overall, evidence isn't strong enough to show that the Mediterranean diet reduces Alzheimer's disease risk. One issue is that most studies on the effects of diet on dementia are based on dietary questionnaires completed by participants who may have trouble recalling what they ate or have memory problems.

So, one study used a modified food questionnaire developed for use in older adults to address this issue. The study looked at whether following a Mediterranean diet, the Dietary Approaches to Stop Hypertension (DASH) diet designed to treat high blood pressure or a hybrid diet that combined aspects of both diets known as the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet could reduce the risk of Alzheimer's disease.

The results showed that people who strictly followed any of the three diets had a lower risk of Alzheimer's disease. Moreover, even modest adoption of the MIND diet approach, such as eating two vegetable servings a day, two berry servings a week and one fish meal a week, appeared to lower the risk of Alzheimer's disease.

More research and clinical trials are needed to know to what degree a Mediterranean diet prevents Alzheimer's or slows the progression of cognitive decline. Nonetheless, eating a healthy diet is important to stay physically and mentally fit. (Mayo Clinic, Jonathan Graff-Radford, M.D.) 

The heart-healthy Mediterranean diet is a healthy eating plan based on typical foods and recipes of Mediterranean-style cooking. Here's how to adopt the Mediterranean diet.

by Mayo Clinic Staff

If you're looking for a heart-healthy eating plan, the Mediterranean diet might be right for you.

The Mediterranean diet incorporates the basics of healthy eating — plus a splash of flavorful olive oil and perhaps a glass of red wine — among other components characterizing the traditional cooking style of countries bordering the Mediterranean Sea.

Most healthy diets include fruits, vegetables, fish and whole grains, and limit unhealthy fats. While these parts of a healthy diet are tried-and-true, subtle variations or differences in proportions of certain foods may make a difference in your risk of heart disease.

Benefits of the Mediterranean diet

Research has shown that the traditional Mediterranean diet reduces the risk of heart disease. The diet has been associated with a lower level of oxidized low-density lipoprotein (LDL) cholesterol — the "bad" cholesterol that's more likely to build up deposits in your arteries.

In fact, a meta-analysis of more than 1.5 million healthy adults demonstrated that following a Mediterranean diet was associated with a reduced risk of cardiovascular mortality as well as overall mortality.

The Mediterranean diet is also associated with a reduced incidence of cancer, and Parkinson's and Alzheimer's diseases. Women who eat a Mediterranean diet supplemented with extra-virgin olive oil and mixed nuts may have a reduced risk of breast cancer.

For these reasons, most if not all major scientific organizations encourage healthy adults to adapt a style of eating like that of the Mediterranean diet for prevention of major chronic diseases.

Key components of the Mediterranean diet

The Mediterranean diet emphasizes:

·       Eating primarily plant-based foods, such as fruits and vegetables, whole grains, legumes and nuts

·       Replacing butter with healthy fats such as olive oil and canola oil

·       Using herbs and spices instead of salt to flavor foods

·       Limiting red meat to no more than a few times a month

·       Eating fish and poultry at least twice a week

·       Enjoying meals with family and friends

·       Drinking red wine in moderation (optional)

·       Getting plenty of exercise

Fruits, vegetables, nuts and grains

The Mediterranean diet traditionally includes fruits, vegetables, pasta and rice. For example, residents of Greece eat very little red meat and average nine servings a day of antioxidant-rich fruits and vegetables.

Grains in the Mediterranean region are typically whole grain and usually contain very few unhealthy trans fats, and bread is an important part of the diet there. However, throughout the Mediterranean region, bread is eaten plain or dipped in olive oil — not eaten with butter or margarine, which contain saturated or trans fats.

Nuts are another part of a healthy Mediterranean diet. Nuts are high in fat (approximately 80 percent of their calories come from fat), but most of the fat is not saturated. Because nuts are high in calories, they should not be eaten in large amounts — generally no more than a handful a day. Avoid candied or honey-roasted and heavily salted nuts.

Healthy fats

The focus of the Mediterranean diet isn't on limiting total fat consumption, but rather to make wise choices about the types of fat you eat. The Mediterranean diet discourages saturated fats and hydrogenated oils (trans fats), both of which contribute to heart disease.

The Mediterranean diet features olive oil as the primary source of fat. Olive oil provides monounsaturated fat — a type of fat that can help reduce LDL cholesterol levels when used in place of saturated or trans fats.

"Extra-virgin" and "virgin" olive oils — the least processed forms — also contain the highest levels of the protective plant compounds that provide antioxidant effects.

Monounsaturated fats and polyunsaturated fats, such as canola oil and some nuts, contain the beneficial linolenic acid (a type of omega-3 fatty acid). Omega-3 fatty acids lower triglycerides, decrease blood clotting, are associated with decreased sudden heart attack, improve the health of your blood vessels, and help moderate blood pressure.

Fatty fish — such as mackerel, lake trout, herring, sardines, albacore tuna and salmon — are rich sources of omega-3 fatty acids. Fish is eaten on a regular basis in the Mediterranean diet.

Wine

The health effects of alcohol have been debated for many years, and some doctors are reluctant to encourage alcohol consumption because of the health consequences of excessive drinking.

However, alcohol — in moderation — has been associated with a reduced risk of heart disease in some research studies.

The Mediterranean diet typically includes a moderate amount of wine. This means no more than 5 ounces (148 milliliters) of wine daily for women (or men over age 65), and no more than 10 ounces (296 milliliters) of wine daily for men under age 65.

If you're unable to limit your alcohol intake to the amounts defined above, if you have a personal or family history of alcohol abuse, or if you have heart or liver disease, refrain from drinking wine or any other alcohol.

Putting it all together

The Mediterranean diet is a delicious and healthy way to eat. Many people who switch to this style of eating say they'll never eat any other way. Here are some specific steps to get you started:

·       Eat your veggies and fruits — and switch to whole grains.An abundance and variety of plant foods should make up the majority of your meals. Strive for seven to 10 servings a day of veggies and fruits. Switch to whole-grain bread and cereal, and begin to eat more whole-grain rice and pasta products.

·       Go nuts. Keep almonds, cashews, pistachios and walnuts on hand for a quick snack. Choose natural peanut butter, rather than the kind with hydrogenated fat added. Try tahini (blended sesame seeds) as a dip or spread for bread.

·       Pass on the butter. Try olive or canola oil as a healthy replacement for butter or margarine. Use it in cooking. Dip bread in flavored olive oil or lightly spread it on whole-grain bread for a tasty alternative to butter. Or try tahini as a dip or spread.

·       Spice it up. Herbs and spices make food tasty and are also rich in health-promoting substances. Season your meals with herbs and spices rather than salt.

·       Go fish. Eat fish once or twice a week. Fresh or water-packed tuna, salmon, trout, mackerel and herring are healthy choices. Grilled fish tastes good and requires little cleanup. Avoid fried fish, unless it's sauteed in a small amount of canola oil.

·       Rein in the red meat. Substitute fish and poultry for red meat. When eaten, make sure it's lean and keep portions small (about the size of a deck of cards). Also avoid sausage, bacon and other high-fat meats.

·       Choose low-fat dairy. Limit higher fat dairy products such as whole or 2 percent milk, cheese and ice cream. Switch to skim milk, fat-free yogurt and low-fat cheese.

·       Raise a glass to healthy eating. If it's OK with your doctor, have a glass of wine at dinner. If you don't drink alcohol, you don't need to start. Drinking purple grape juice may be an alternative to wine.