Diet and blood pressure

Importance of Diet with High Blood Pressure

If you are overweight and have high blood pressure, a first step is to lose weight, usually through a combination of calorie reduction and increased physical activity. Eating certain kinds of food and avoiding others also may help you reduce your blood pressure or keep it from getting high in the first place.

See the article on High blood pressure, to learn more about the causes of it.

Some dietary factors to consider in preventing and treating hypertension are:

Salt and Sodium

Many studies in diverse populations have shown that a high-sodium intake is associated with higher blood pressure. The National Academy of Sciences, the American Heart Association, and the federal government's "Dietary Guidelines for Americans" recommend limiting sodium intake to 2,400 milligrams a day.

For cooking at home, low-salt and low-sodium cookbooks abound. Or simply spare the salt and, if you like, substitute other spices and flavorings, such as pepper, garlic, ginger, onion, or lemon juice. Watch out for some flavorings and ingredients, such as monosodium glutamate (Accent, for example), soy sauce, and some spice mixtures that contain large quantities of sodium.

Also, many processed foods are high in salt and other sodium-containing ingredients.

You can tell how much sodium is in packaged foods by reading the Nutrition Facts panel on food labels. There, manufacturers must list the amount of sodium (in milligrams) in a serving of the food and show (as a percentage) how that amount contributes to the daily reference value for sodium, which is 2,400 milligrams.

To quickly identify foods with lower sodium contents, look for products with label claims like "no salt added," "low sodium" or "two-thirds less salt." These claims must meet government-enforced definitions, so that they mean the same for any product on which they appear.

If you eat out a lot, you may want to ask restaurants to hold the salt in your orders. Some may already offer lower sodium foods on their menus, so look for menu items with claims like "low sodium." Nutrition claims on menus must mean the same as they do on packaged food. (See "Today's Special: Nutrition Information" in the May-June 1997 FDA Consumer.)

Before using salt substitutes, which contain potassium chloride, check with your doctor just to make sure they're all right for you. In general, an increase in potassium can help attain a normal blood pressure, but there may be other factors, such as medicines you are taking and other health factors, that need to be considered.

(For more on salt in the diet, see "A Pinch of Controversy Shakes Up Dietary Salt" in the November-December 1997 FDA Consumer.)

Alcohol

Some studies show that low to moderate consumption of alcohol, especially wine, may help reduce heart disease risks. But excessive amounts of alcohol are known to raise blood pressure. Also, if you're trying to lose weight, you need to remember that alcoholic beverages are calorie dense, providing about 100 to 145 calories a drink but little nutritional benefit. Ask your doctor what is best for you when it comes to alcohol consumption.

Calcium and Magnesium

Some studies have shown that people whose intakes of calcium are low are more likely to have high blood pressure, but a link has not been proven. The same is true of magnesium. Though the science is uncertain at this time, it can't hurt to eat a diet with sufficient calcium and magnesium. Good sources of calcium are dairy products, such as milk, yogurt and cheese. Choose low-fat or nonfat versions of these foods. Other sources of calcium are canned salmon, collard greens, broccoli, soy milk, tofu, and calcium-fortified orange juice and grain products. Good sources of magnesium are whole grains, green leafy vegetables, nuts, and legumes.

Check the Nutrition Facts panel on food labels to learn how much calcium is in a food. The amount of calcium in a serving and how that amount contributes to the daily reference value for calcium must be listed for all foods. Information about a food's magnesium content may be offered voluntarily.

DASH Diet

In 1997, the National Heart, Lung, and Blood Institute of the National Institutes of Health released an eating plan that was found in clinical studies to lower systolic blood pressure by 5.5 points and diastolic pressure by 3. According to researchers, blood pressure reductions were seen within two weeks of starting the meal plan and maintained for the rest of the eight weeks of study by men, women, whites and minorities alike. This meal plan, called Dietary Approaches to Stop Hypertension, or DASH for short, calls for a food intake similar to that recommended in the federal government's "Dietary Guidelines for Americans."

More information on the DASH diet is available on the Internet from the National Heart, Lung, and Blood Institute, which is part of the National Institutes of Health.

This meal plan is based on 2,000 calories a day. Depending on your calorie needs, your number of daily servings may vary from those listed. Consult your doctor or a dietitian to determine your calorie needs.

This break down includes: Food Group, Daily Servings, Serving Size

Grains and grain products

7 to 8 
1 slice bread

1/2 to 1-1/4 cup dry cereal

1/2 cup cooked rice, pasta, or cereal

Vegetables

4 to 5 
1 cup raw leafy vegetables

1/2 cup cooked vegetable

6 oz vegetable juice

Fruits

4 to 5 
6 oz fruit juice

1/4 cup dried fruit

1 medium fruit

1/2 cup fresh, frozen or canned fruit

Low-fat or nonfat dairy foods

2 to 3 
8 oz milk

1 cup yogurt

1-1/2 oz cheese

Meats, poultry, fish

2 or fewer 
3 oz cooked lean meat, poultry (skinless white meat ), or fish

Nuts, seeds and dry beans

4 to 5 per week 
1/3 cup nuts

2 Tbsp seeds

1/2 cup legumes

Fats and oils

2 to 3 
1 tsp soft margarine or butter

1 tsp regular mayonnaise or 1 Tbsp low-fat mayonnaise

1 Tbsp salad dressing or 2 Tbsp "light" salad dressing

1 tsp oil (olive, corn, canola, safflower, or other)

Sweets

5 per week 
1 Tbsp maple syrup, sugar or jelly

1/2 cup sherbet

3 pieces of hard candy

(Source: National Heart, Lung, and Blood Institute)

For More Information

National Heart, Lung, and Blood Institute Information Center P.O. Box 30105 Bethesda, MD 20824-0105 1-800-575-WELL (1-800-575-9355) www.nhlbi.nih.gov/hbp/index.html

American Heart Association 7272 Greenville Ave. Dallas, TX 75231 1-800-AHA-USA1 (1-800-242-8721) www.americanheart.org