GETTING THE NUMBERS DOWN
High blood pressure quietly sneaks around your body, causing damage here and wreaking havoc there. It can cause so much strain on your heart that the organ fails from working so hard. It can make arteries in your brain rupture or develop blockages, potentially leaving you disabled. It can hurt your kidneys so badly that you need to use a dialysis machine, and your eyes so much that you become blind.
If you think that’s bad, here’s the really scary part: Since high blood pressure usually causes no symptoms, you might not even know you have it until you develop a serious health problem.
But while high blood pressure works quietly, it’s frequently deadly (for this reason, high blood pressure is often called the silent killer). “High blood pressure is just a reflection of a cardiovascular system that’s about to burst internally,” says John A. McDougall, MD, medical director of the McDougall Program in Santa Rosa, California, and author of The McDougall Program for a Healthy Heart. “But if you eat a good diet—lots of fruits and vegetables and whole grains versus rich foods—you can help change all that,” he says.
According to the National Institutes of Health, nearly one in three adults has high blood pressure. By eating a healthy diet, you can help ensure that you won’t be one of them.
Everyone has blood pressure, and it can go up or down frequently during the course of a day, and even from minute to minute. Your heart pumps blood throughout your body through a system of arteries. Each time your heart beats, it sends out a new wave of blood, and your blood pressure goes up. This is your systolic blood pressure. Between beats, your heart briefly relaxes and the pressure subsides. This is your diastolic blood pressure. When you have your blood pressure tested, you’re given two numbers, one over the other (your systolic over your diastolic), measured in millimeters of mercury, or mm Hg. A sample blood pressure might be 135/86 mm Hg.
Your heart, brain, kidneys, eyes, and other organs depend on a reliable flow of blood that courses through your delicate “plumbing.” When you develop chronic high blood pressure, or hypertension, trouble follows.
High-pressure blood whooshes through the arteries with damaging force. Your heart has to struggle harder to push out the blood, and it may grow enlarged and unable to bear the extra strain. Your arteries, which should be elastic and flexible, may more rapidly grow stiff and narrow. They may deliver less blood to your organs, and a blood clot can more readily get “stuck” and totally block the flow, causing a heart attack.
In most cases, doctors don’t know the exact cause of high blood pressure. But they do know the preventable lifestyle factors that increase your risk of the problem: being overweight or obese, excessive alcohol use, a diet that provides too much salt or too little potassium, smoking, a sedentary lifestyle, chronic stress, and taking certain medications. Other risk factors can’t be changed: your age (high blood pressure is more common in middle age and after), your race (it’s more common in African Americans than Caucasians), and family history of high blood pressure.
The National Institutes of Health (NIH) and the American Heart Association use the following classifications to identify normal and high blood pressure:
| Blood Pressure Classification | Systolic Blood Pressure (in mm Hg) |
Diastolic Blood Pressure (in mm Hg) |
|
| Normal | Less than 120 | and | Less than 80 |
| Prehypertension | 120 to 139 | or | 80 to 89 |
| Stage 1 hypertension | 140 to 159 | or | 90 to 99 |
| Stage 2 hypertension | More than 160 | or | More than 100 |
Even if your blood pressure falls into the normal or “prehypertension” categories, it’s not time to breathe a sigh of relief. Your risk of death from heart disease or stroke rises progressively as your blood pressure goes up, and according to the NIH, the risk starts going up in these early stages. In other words—you need to start getting concerned well before you have a diagnosis of hypertension.
Research from the major, long-running Framingham Heart Study shows that having systolic blood pressure between 130 and 139 or diastolic blood pressure between 85 and 89 may more than double your risk of cardiovascular disease versus having blood pressure in the “normal” range.
According to the NIH, people in the prehypertension category should be “firmly and unambiguously advised to practice lifestyle modifications in order to reduce their risk of developing hypertension in the future.”
Mild high blood pressure responds well to nondrug therapies. If you feed and exercise your body well, you may be able to avoid blood pressure drugs (and their often troublesome side effects) and calm your rushing blood. Don’t be misled by the “mild” label, though. “Most heart attacks and strokes that occur do so in people with stage 1 high blood pressure,” says Norman Kaplan, MD, professor of internal medicine and hypertension specialist at the University of Texas Southwestern Medical Center at Dallas.
A major study published in the Journal of the American Medical Association measured the effects of lifestyle changes on 810 adults with “above optimal” blood pressure. They were divided into three groups. One received many counseling sessions on how to reduce blood pressure with lifestyle measures such as weight loss, physical activity, and a low-sodium diet. Another got counseling, plus lots of information on the DASH diet for lowering blood pressure, which is rich in fruits and vegetables (more on that later). The third group received a single 30-minute counseling session covering these basics on lowering blood pressure.
After 6 months, the first group reduced their systolic blood pressure by an average of 3.7 mm Hg, and the DASH diet group reduced theirs by 4.3 mm Hg. The third group had less impressive changes in their blood pressure. At the beginning of the experiment, 38 percent of the subjects had hypertension, but after 6 months, only 17 percent in the first group had it, and only 12 percent in the DASH group. This contrasted with a considerably higher 26 percent in the advice-only group.
In a scientific statement from the American Heart Association on dietary approaches to prevent and treat high blood pressure, the first suggestion from the expert panel was to maintain a healthy weight. Almost all studies have documented that “weight loss lowers blood pressure,” they wrote. You don’t have to get down to a perfect weight before your blood pressure starts dropping, either. Just a few pounds will make a difference. But the more weight you lose as you pursue your goal of a healthy target weight, the more your blood pressure will drop. Ideally your body mass index, or BMI (a way to classify your weight’s effect on your health), should be no higher than 25. That translates to a person who’s 5 feet 4 inches weighing no more than 145 pounds, or someone who’s 6 feet tall weighing 184 pounds max.
As an added bonus, losing weight may improve your blood pressure enough that you can stop taking hypertension medications (although you shouldn’t change your medication regimen without your doctor’s guidance).
Losing weight—even just 10 pounds—can reduce your blood pressure or prevent you from developing hypertension.
What’s the connection between excess weight and hypertension? The more tissue you have in your body, the harder your heart has to pump to feed it. And that work exerts more pressure on artery walls.
Everybody knows that losing weight is no piece of cake. But exercise makes it easier. And the best weight-loss diet is the same as the best diet for controlling blood pressure: low-fat foods and lots of fruits and vegetables.
“We really emphasize following a low-fat, high-fruit-and-vegetable diet. It’s almost certain to lower your blood pressure because it lowers sodium and increases all the good stuff that’s hypothesized to lower blood pressure—fiber, calcium, and potassium—and it’s an effective avenue to weight loss,” says Pao-Hwa Lin, PhD, assistant research professor of medicine at Duke University in Durham, North Carolina, and coauthor of The DASH Diet for Hypertension.
A diet low in fat won’t include large amounts of red meat, which is packed with saturated fat. Nor will it include many processed foods, because they’re high-fat minefields. Processed foods also tend to be high in salt and low in potassium, so when you get rid of them, you wipe out three bad birds with one dietary stone.
Experts believe that many people with high blood pressure are salt “responders,” meaning that their blood pressure levels depend on the amount of salt they eat. “But there is some controversy about the issue,” says Lawrence Appel, MD, professor of medicine and epidemiology at Johns Hopkins University School of Medicine in Baltimore. “Some people have a greater response than others. Older people tend to be more sensitive to salt, as are African Americans.” Some research shows that roughly 26 percent of Americans with normal blood pressure—and about 58 percent of those with hypertension—are salt sensitive.
Here’s what happens. When you eat the typical American’s ration of sodium—3,000 to 6,000 milligrams or more a day, compared with the recommended 2,400-milligram limit—your blood pressure rises. If you’re sensitive to salt, the sodium it contains makes your body attract water like a sponge. You soak it up, and your blood vessels expand with it, producing higher pressure.
Some experts feel that you shouldn’t worry much about whether you’re salt sensitive or not. It’s hard to determine an individual’s sensitivity to salt—you’re better off just reducing your salt intake to the recommended limits to be safe.
“If you have high blood pressure, your sodium needs to be reduced by half,” says Dr. Kaplan. “Don’t put salt on the table or in the food you cook. Avoid most processed foods, which is where 80 percent of the sodium in American diets comes from. If that doesn’t bring your blood pressure down, then sodium isn’t the culprit,” he says.
According to the NIH, reducing sodium in your diet to no more than 2,400 milligrams daily (equal to about a teaspoon of table salt) will lower your systolic blood pressure by 2 to 8 mm Hg. An even better goal is to reduce daily sodium to 1,500 milligrams, or ⅔ teaspoon of table salt, to lower your blood pressure even further.
Potassium and calcium are two minerals that act like a massage on a tense body. They help the blood vessels relax. When arteries relax, they dilate, or open up, and give blood the room it needs to move calmly.
“You can think of potassium as the opposite of sodium,” says Harvey B. Simon, MD, associate professor of medicine at Harvard Medical School. Potassium helps the body excrete sodium, so the more potassium you get in your diet, the more sodium you get rid of. In fact, the landmark INTERSALT study looked at more than 10,000 people from 32 countries and found that people with the highest amounts of potassium in their blood had the lowest blood pressures, and those with the lowest amounts had the highest.
“Fruits and vegetables are naturally low in sodium and high in potassium,” says Dr. Lin. “A diet high in vegetables and fruits almost mimics a vegetarian diet, which is known to be linked to lower blood pressure,” she says. Foods that are especially rich in potassium include beans, potatoes, avocados, steamed clams, lima beans, bananas, and apricots.
Calcium has shown similar ties to blood pressure in studies. Some have found that low intake is actually a risk factor for developing high blood pressure. The landmark Framingham Heart Study looked at the calcium intakes of 432 men. Those who ate the most (between 322 and 1,118 milligrams a day) had a 20 percent lower risk of developing high blood pressure than those who ate the least (8 to 109 milligrams a day).
A study in the journal Hypertension that analyzed the diet habits of nearly 5,000 people found that as they consumed more dairy, they became less likely to have hypertension. In fact, the people who consumed the most dairy were nearly 40 percent less likely to have hypertension as the people who consumed the least. However, this association was mainly seen in people whose diets were relatively low in saturated fat. Since regular dairy foods contain saturated fat, it’s wise to make sure that you get your calcium from low-fat or fat-free dairy products.
A cup of fat-free yogurt contains about 415 milligrams of calcium and a glass of fat-free milk has about 352. Besides low-fat and fat-free dairy products, your best sources of calcium include tofu, calcium-fortified orange juice, kale, broccoli, and collard greens.
The government-promoted DASH diet—for Dietary Approaches to Stop Hypertension—is heavy on whole grains (six to eight daily servings) and fruits and vegetables (eight to 10 servings). It calls for two or three servings of low-fat dairy; moderate amounts of lean meat, nuts, and seeds; and limited amounts of fats and oils and sweets. It urges you to eat processed foods sparingly, since these are the main source of sodium in the American diet.
Adopting the DASH plan can lower your systolic blood pressure by 8 to 14 mm Hg. As you can see, by cutting out the salt and sodium and boosting fruits, vegetables, and other plant foods, the blood pressure reductions really add up.
For starters, you should practice what Dr. Appel calls active shopping. In other words, read the nutrition labels and be sure to glance at the sodium content. One 8-ounce can of stewed tomatoes can contain over 800 milligrams of sodium, while another can might have only 70. “You often have to look hard for low-sodium cereals,” he adds. “Shredded wheat is one of the low-salt ones.”
Sodium-free is a good phrase to look for on a label. So is low-sodium. The word light, however, is not as conclusive. Light soy sauce, for instance, can still have 605 milligrams of sodium per tablespoon. No salt added doesn’t mean a food is sodium-free, either. In the Nutrition Facts box on a food label, also look to see how the sodium in the food relates to the Daily Value (DV). Go for foods containing less than 5 percent of the DV. If the product contains 20 percent or more of the DV, it’s high in sodium.
While bread is often a nutritious, wholesome food, it too is occasionally high in salt. If you buy bread fresh at a bakery where it isn’t labeled, don’t be shy about asking how much salt is in each loaf.
When you’re buying canned foods, like the tomatoes mentioned above, salt can be a real problem. In many cases, however, rinsing the food will eliminate a good percentage of the salt. If you don’t have a can of beans that states it’s low-sodium, for example, you can rinse off at least half the salt the food was packed in, says Neva Cochran, RD, a nutrition consultant in Dallas.
Since produce is the cornerstone of a diet for healthy blood pressure, you should always be looking for ways to eat more fruits and vegetables. Here are a few of Dr. Lin’s suggestions:
When you’re picking up produce, be sure to grab some apples, pears, and oranges. These three fruits are fiber kings. And heart researchers are starting to find that not only does fiber decrease dangerous cholesterol, it may also lower blood pressure. Fruit fiber made a strong showing in a study at Harvard Medical School, where scientists tracked more than 30,000 men. The men in the study who ate less than 12 grams of fruit fiber a day (about four oranges or three apples or pears) were 60 percent more likely to develop high blood pressure. The DASH diet is particularly high in fiber, given the amount of grain foods, fruits, and vegetables it recommends.
Finally, it’s essential to reduce the amount of fat in your diet. You don’t have to be fanatical, however. Instead of cutting out fat with a cleaver, start by slicing it off with a scalpel, bit by bit. Dr. Lin recommends making small, gradual changes that will cut the total amount of fat you use in half. Buy butter substitutes and trans-fat-free versions of margarine. For sautéing, use olive oil cooking spray instead of liquid oils or butter. Use mustard instead of mayonnaise, and snack on low-salt pretzels instead of potato chips.
If you’re sodium savvy and watching your blood pressure, you already know to say no thanks to foods such as chips and salty pickles. Yet sodium appears in many foods in which you might not expect it. Baking soda and baking powder, for instance, are both sodium bicarbonate. Dried fruit contains sodium sulfite, and ice cream often has sodium caseinate and sodium alginate.
Even a sharp-eyed sodium detective can miss a few salt mines. Here are some to watch out for:
Instant chocolate-flavored pudding. A half-cup contains 470 milligrams of sodium, more than the amount in two slices of bacon.
Ketchup. One tablespoon contains 156 milligrams of sodium.
Pastries. A fruit Danish has 333 milligrams of sodium, while a cheese Danish has 319. Scones and baking-powder biscuits also tend to be high in sodium.
Cheese. Most types are high in sodium. This includes cottage cheese, which has 425 milligrams in a half-cup serving.
Research has found that 16 percent of hypertensive disease worldwide is due to alcohol use.
The NIH recommends that men drink no more than two drinks daily, and women (and men of slight physical stature) keep their consumption limited to one drink daily. One drink is the equivalent of a 12-ounce beer, 5 ounces of wine, or 1½ ounces of 80-proof liquor.
By staying moderate with your alcohol use, you can reduce your systolic blood pressure by 2 to 4 mm Hg.