U.S. Food and Drug Administration
FDA Consumer magazine
July-August 1999
Table of Contents
by Paula Kurtzweil
The "silent killer"--hypertension, or high blood pressure--snuck up on my mother when she was in her 40s, making its presence known by causing congestive heart failure and resulting in several lengthy hospital stays.
Though her blood pressure measured as high as 250/150 during those initial touch-and-go days, she's maintained a much-closer-to-normal blood pressure for the past 30 years, thanks to daily doses of antihypertensive drugs.
Today's range of drugs for treating high blood pressure makes it possible for people like my mother and the nearly 50 million other Americans who suffer from high blood pressure to lead normal, healthy lives well into their senior years. Exercise, regular blood pressure checks, healthy eating, maintenance of a healthy body weight, and other lifestyle changes can make a big difference, too.
Without these treatments, people with consistently high blood pressure face increased risks for heart attack, stroke and kidney disease. High blood pressure also can cause blood vessels on the eye's retina to clog, eventually bursting and possibly damaging parts of the retina and impairing vision.
What Is Blood Pressure?
Blood pressure is the force of blood against the blood vessel wall. High blood pressure occurs when there is increased tension or pressure in the arteries. The greater the pressure, the harder the heart has to work.
Blood pressure is measured with a device called a sphygmomanometer, which can be either manual or electronic. The blood pressure reading is written as a fraction: for example, 120/80.
The first number is the systolic pressure, which is the point at which the heart contracts to push the blood out to the rest of the body. When blood pressure is taken manually, this is the number at which a person taking the blood pressure first hears a pulse through the stethoscope. When an electronic device is used, the number appears on the display.
The second number is called the diastolic pressure, which represents the lowest point in the pressure of blood--right before another squirt of blood enters the arteries. When the blood pressure is measured manually, this number is the point at which the person listening through the stethoscope stops hearing a pulse. On an electronic device, this number also automatically appears on the display.
Many people think that 120/80 is the perfect or normal blood pressure. But, says Robert Fenichel, M.D., deputy director of FDA's division of cardiovascular and renal drug products, "If your pressure is lower than that, good for you."
Deciding What's High
Elevated blood pressure rarely makes itself known; it usually has no symptoms. That's why it's often referred to as the silent killer. Feeling nervous or tense, for example, doesn't necessarily translate into elevated blood pressure. Getting periodic blood pressure checks is the only way to catch high blood pressure early.
According to the National Heart, Lung, and Blood Institute of the National Institutes of Health, a blood pressure reading consistently higher than 140/90 is a sign that the blood pressure needs to be brought under control.
Most doctors don't diagnose a person with high blood pressure on the basis of only one reading. People who find a visit to the doctor's office unnerving can have "white-coat hypertension," blood pressure that is only high when taken in the doctor's office. ("White coat" refers to the ubiquitous white lab coats many health professionals wear.) Others may have "labile hypertension," blood pressure that gets slightly elevated in certain situations but which is normal most of the time.
To rule these out, doctors may take a patient's blood pressure later during the office visit and ask the patient to come back for two more visits, taking two readings during each of those visits. Many doctors also ask patients with elevated blood pressure to have their blood pressure checked in a setting other than a medical one. With one of the many electronic blood pressure measuring devices that consumers can buy without a doctor's prescription, patients often can check and record their blood pressure at home. To get as accurate a reading as possible, the doctor may ask the patient to bring the device in to the office to make sure it is calibrated properly. This can usually be done by comparing the device's readings with readings taken at the same time with the doctor's blood pressure equipment.
If a patient has consistently high readings in and out of the medical setting, the doctor will decide what type of treatment is appropriate: diet modification, increased exercise, medicine, or a combination of these.
Treating Hypertension
Treatment can vary with the level of elevation of the blood pressure, as well as the patient's age and health. (See "Treating High Blood Pressure.") According to FDA's Fenichel, sometimes lifestyle changes can reduce blood pressure by 5 points or so. They include stopping smoking, reducing alcohol intake, losing excess weight, and making certain dietary changes, such as reducing sodium intake and possibly increasing potassium, calcium and magnesium intake. (See "Diet and Blood Pressure.") Some experts also recommend exercise and relaxation techniques, such as meditation.
"But," Fenichel says, "treatment with drugs is the only effective approach for attaining larger reductions in blood pressure."
FDA has approved numerous drugs for treating hypertension. These drugs work in different ways but the end result--reducing blood pressure--is the same.
Some of the most commonly used drugs to treat high blood pressure are:
Often, combinations of two drugs from different classes are used to improve the drugs' effectiveness.
Many doctors begin newly diagnosed hypertensive patients with diuretics or beta blockers. The Sixth Report of the Joint National Committee (JNC) on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure, released by NIH's National Heart, Lung, and Blood Institute in November 1997, recommends diuretics or beta blockers as the first line of treatment. However, based on a patient's situation--for example, use of other medicines--doctors may choose to start treatment with another antihypertensive drug.
Some specifics to JNC's first-line recommendation are noted in the report--for example, it recommends that in African Americans, one of the groups most at risk for hypertension, diuretics alone should be the first agent of choice--provided there are not other conditions that prohibit their use--because of this group's increased sensitivity to salt. For hypertensive people with diabetes or kidney disease, the guidelines recommend that initial drug treatments include ACE inhibitors.
Finding What Works
Like most drugs, blood pressure medicines can have side effects, ranging from the unpleasant--such as skin rash, sleepiness and weight gain--to the severe, including depression, hallucinations, heart dysfunction, and liver disease. Patients who begin a drug treatment and develop symptoms that they did not have before should discuss them with their doctors. With the great variety of medicines, it is likely that another antihypertensive drug or dosage level can help control blood pressure with few or no side effects.
In my mother's 30-year history of high blood pressure, she's switched drugs only a few times or varied the dosages, mainly to gain better control of her blood pressure. But she's never had any qualms about taking the medicine.
"I had a lot of relatives who probably had the same problem I do, but they died early because they didn't have the medicines that they do now," she says. "I'm thankful to have them. I wouldn't be around enjoying the good life that I do."
Paula Kurtzweil is a member of FDA's public affairs staff. Judith Willis, also a member of FDA's public affairs staff, contributed to this article.
Those at greater risk for high blood pressure, according to the National Heart, Lung, and Blood Institute, include:
In addition, as many as 65 percent of people with diabetes have high blood pressure.
--P.K.
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.
Some dietary factors to consider in preventing and treating hypertension are:
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.)
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.
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.
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.
| 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 salad dressing or 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)
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
Hypertension Network
www.bloodpressure.com [Note, 11-18-2005: The URL for
this organization is no longer active.]
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