Heart-Healthy Diets
Diet plays an important role in the health of the heart. There is no single diet that suits everyone, but at this time the Mediterranean diet appears to have the most favorable findings. Of note, weight control, quitting smoking, and exercise are essential companions of any diet program. [For detailed information, see Well-Connected Report #43 Heart Healthy Diet.]
Mediterranean Diet
The Mediterranean diet is rich in heart-healthy fiber and nutrients, including omega-3 fatty acids and antioxidants. Evidence now strongly indicates that this dietary approach may be the most important for protecting the heart and extending survival. The diet recommends the following:
- A relatively high fat intake (about 35% to 45% of daily calories, mostly in monounsaturated and polyunsaturated fats). The Mediterranean diet is known for its use of olive oil, but the greatest benefits found in a major study of this diet appeared to be derived from the use of canola oil, which is rich in omega-3 fatty acids. Olive oil, in fact, does not contain omega-3 fatty acids. On the other hand, olive oil may have beneficial effects independent from those on lipids, such as improving insulin and blood glucose levels and reducing blood pressure.
- Daily glass or two of wine.
- The same protein intake as the AHA, although fish is the primary source. (It avoids high-fat dairy and meat products.) In fact, one 2001 study suggested that fish-consumption, not wine, is the heart-protective ingredient in this diet.
- Lower carbohydrate intake than AHA. Emphasizes not only fresh fruits and vegetables, but also higher amounts of nuts, legumes, beans, and whole grains.
- Foods seasoned with garlic, onions, and herbs.
Therapeutic Lifestyle Changes (TLC) from the National Cholesterol Education Program
Guidelines in 2001 from the National Cholesterol Education Program include the following for preventing and managing high cholesterol levels in adults:
- Choose five or more servings of fresh fruits and vegetables and six or more servings of whole grains, legumes. Soluble fiber is preferred (from cereal grains, beans, peas, legumes, and many fruits and vegetables).
- Fats can be up to 35% of daily calories, but no more than 7% should be from saturated fat. (People with high triglycerides or low HDL or both may need a higher fat intake.) Choose fats containing unsaturated fatty acids (from vegetables, fish, legumes, and nuts). Choose margarines containing sterols or stanols (e.g., Benecol, Take Control). Avoid trans fatty acids found in commercial products as much as possible.
- Proteins choices should be limited in general to fat-free and low-fat milk products, fish, legumes, skinless poultry, and lean means.
- Limit cholesterol intake to less than 200 mg per day.
- Maintain healthy body weight and a healthy level of physical fitness.
The Ornish Program and Severely Fat-Restricted Diets
The Ornish program limits saturated fats as much as possible, reduces total fat to 10%, and increases carbohydrates to 75% of calories. It is a very effective but demanding regimen:
- It excludes all oils and animal products except nonfat yogurt, nonfat milk, and egg whites.
- Foods stressed are whole grains, legumes, and fresh fruits and vegetables.
- People in the program exercise 90 minutes at least three times a week.
- Stress reduction techniques are employed.
- People do not smoke nor do they drink more than two ounces of alcohol per day.
Everyone on low fat diets should consume a wide variety of foods and take a multivitamin if appropriate.
High-Protein Diets
High-protein diets, such as the Atkins and South Beach diets, are proving to be very effective in producing short-term weight loss. Because of their emphasis on fats and proteins, many experts are concerned about long-term health problems. Still, significant studies are reporting benefits on cholesterol and blood sugar levels. Centers that promote this approach argue that heart problems from obesity are due to insulin disturbances from sugar imbalances. Therefore, they believe that restricting carbohydrates is the best approach for obesity--and especially for overweight people with diabetes. More research is needed, however, to determine the long-term impact on health.
The DASH Diet
The DASH diet (Dietary Approaches to Stop Hypertension) is proving to help lower blood pressure after eight weeks. Restricting sodium improves results. The diet appears to have antioxidant effects and may even prove to be a good diet for lowering LDL cholesterol levels--although the beneficial HDL levels also decline.
This diet is not only rich in important nutrients and fiber but also includes foods that contain far more electrolytes, potassium, calcium, and magnesium, than are found in the average American diet. The dietary recommendations are as follows:
- Avoid saturated fat (although include calcium-rich dairy products that are no- or low-fat).
- When choosing fats, select monounsaturated oils, such as olive or canola oils. (One study reported a reduced need for anti-hypertension medication in people with a high intake of virgin olive oil, but not sunflower oil, a polyunsaturated fat.)
- Choose whole grains over white flour or pasta products.
- Choose fresh fruits and vegetables every day. In one 2002 study, people who increased their intake of fruits and vegetables experienced a drop in blood pressure after six months. Many of these foods are rich in potassium, fiber, or both which may help lower blood pressure.
- Include nuts, seeds, or legumes (dried beans or peas) daily.
- Choose modest amounts of protein (preferably fish, poultry, or soy products). Soy in combination with fiber-rich foods or supplements may have specific benefits. Oily fish may also be particularly beneficial. They contain omega-3 fatty acids, which have been associated with heart and nerve protection.
[For more information, seeWell-Connected Report #14 High Blood Pressure.]
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