One nation, under pressure.

A time bomb in your blood vessels that threatens your heart, brain, and kidneys.

That's one way to think of high blood pressure, or hypertension. It usually causes no aches, no pains, no symptoms. But make no mistake--it's a killer.

What's Your Risk?(*)

  HIGH
 BLOOD      above 140 or above 90
PRESSURE
 BLOOD       130 to 139 or 85 to 89
PRESSURE        (High-normal)
  THAT
INCREASES
 THE RISK    120 to 129 or 80 to 84
OF DISEASE         (Normal)
 OPTIMAL
 BLOOD      below 120 and below 80
PRESSURE

If your systolic and diastolic pressures fall into different categories, your risk depends on the higher category.

(*)numbers apply to adults who aren't taking drugs to lower their blood pressure.

* Heart disease. It's one of the Big Three risk factors (along with smoking and high blood cholesterol). Why? Hypertension speeds up artery-clogging.

* Stroke. It's the biggest risk factor for strokes, which kill more Americans than anything but heart disease and cancer. How? "It accelerates artery-clogging in the brain and causes blood vessels to burst," says Jeremiah Stamler, a hypertension expert at Northwestern University Medical School in Chicago.

High blood pressure also increases the risk of kidney disease, which is life-threatening but less common.

The saving grace: there's time to defuse the bomb before it goes off.

For more than 20 years, that's what a little-known government program with a less-than-catchy name has been trying to do. The National High Blood Pressure Education Program (NHBPEP) has been one heckuva success. Since the late 1970s, the percentage of hypertensive adults whose blood pressures are under control has doubled.(1) Meanwhile, heart disease and stroke deaths have plummeted to half their 1970 rates.

But two years ago, the NHBPEP shifted gears. Instead of just finding and treating the millions who already have high blood pressure, it also decided to try to keep people from getting high blood pressure in the first place. And for good reason.

WHY NOT WAIT?

In the U.S., blood pressure goes up as you age. So why not wait for it to rise and then worry? Because once you have high blood pressure, you can never lower your risk back to where it was.

"Treatment is effective in lowering the risk," says John's Hopkins's Paul Whelton, who chaired the NHBPEP's 1993 Working Group Report on Primary Prevention of Hypertension.(2)

"But under the best circumstances, a treated patient has twice the risk of a heart attack or stroke of someone who never had high blood pressure." By the time their hypertension is diagnosed, many people have suffered some damage to their heart, eyes, kidneys, or brain, he explains.

And then there are the people who never make it to diagnosis. "In about 25 percent of untreated patients, the complication of hypertension will be sudden death," says Whelton.

Once you have hypertension, it needs to be managed by a physician for the rest of your life. And while drugs that lower blood pressure are lifesavers, they come with a cost--economic and otherwise. Sexual impotence in men is the most common side effect.

What's more, only about half of those who take drugs lower their blood pressure below 140 over 90, which is the border between "high-normal" and "high."(1)

The solution: Prevent high blood pressure before it occurs.

A RISING RISK

Preventing high blood pressure isn't like preventing cancer. It's not something you either have or don't have (see "The Risk of Being Normal").

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"We draw a line in the sand and say 'this is hypertension,'" says Whelton. "We do it to say that it's the point where the cost and side effects of using a drug are worth it."

"But the risk of dying of heart disease or stroke doesn't start to rise at 140 over 90," says Rose Stamler, a hypertension researcher at Northwestern University Medical School. "It starts to rise above a systolic pressure of 120 or a diastolic pressure of 80."

(The higher number--or systolic pressure--is the pressure on the blood vessel walls when the heart beats. The lower number--or diastolic pressure--is the pressure between beats.)

WHAT WORKS

What can you do to keep your pressure from rising with age, as it typically does in the U.S.?

1. Cut the salt. "The data are enormous and unambiguous that cutting salt lowers blood pressure," says Whelton.

Thanks to media reports--often inspired by the industry's Salt Institute--some people believe that they're not "sensitive" to salt. In fact, many studies that supposedly show that some people aren't sensitive "are really poor," says Rose Stamler. "As with anything in biology, there's a variation in response. But most of us are sensitive to one degree or another."

Salt is 40 percent sodium. The average American adult consumes about 4,000 milligrams of sodium a day. That's equal to almost two teaspoons of salt.

"In the U.S., the average person's systolic blood pressure rises by 15 points between the ages of 25 and 55," says Stamler. "If salt intake were lower by about one teaspoon a day, the rise would be six, not 15, points. That could mean a 16 percent drop in coronary heart disease deaths, and 23 percent fewer stroke deaths, at age 55."

The problem is that 75 percent of the sodium we eat is hidden in processed foods like soups, frozen dinners, and pizzas. (Only about 15 percent comes from the salt shaker. Ten percent occurs naturally in food.) And most of the food industry is stonewalling efforts to cut the salt.

That makes some physicians shy away from urging their patients to cut back on sodium. "Instead of harassing people to eat less salt, we need to lower sodium in the food supply," says Frank Sacks, a cardiologist at Harvard Medical School.

2. Lose weight. One out of three American adults is overweight. yet shedding even a few pounds can make a big difference.

In the Trials of Hypertension Prevention, people who lost an average of eight pounds by dieting and modest exercise cut their risk of high blood pressure in half.(2) "There's no question that weight-loss prevents hypertension," says Whelton.

3. Get Active. "The first benefit of exercise is that it helps people maintain a healthier weight," says William Haskell, an exercise physiologist at Stanford University. "But exercise has a unique and independent effect on preventing the age-related rise in blood pressure."

And, he says, 30 to 45 minutes of moderate-intensity aerobic exercise, like brisk walking, jogging, hiking, cycling, or swimming, may actually be better than more-exhaustive exercise.(3) "Heavy work may blunt some of the blood-pressure-lowering," says Haskell.

4. Limit alcohol. "Blood pressure is exquisitely sensitive to alcohol," says Johns Hopkins's Paul Whelton. "The evidence is consistent and powerful." But that doesn't mean you have to become a teetotaler.

"There's no good evidence that one or two drinks a day are going to have much effect on blood pressure," says Haskell. It's only those who drink more than two alcoholic beverages a day who will substantially raise their risk for high blood pressure.(2)

5. Eat potassium-rich foods. In 1993, when the National High Blood Pressure Education Program issued its report on preventing high blood pressure, potassium wasn't in the "proven" column.(2) But since then, says Northwestern University's Jeremiah Stamler, "the evidence has continued to mount."

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While it's less massive, the data for potassium mirrors that for sodium:

* Animals. In rats, a high-salt diet raises blood pressure. A high-potassium diet protects against strokes caused by salt.(4)

* Population studies. The best, by far, is the INTERSALT study, which compared blood pressures in more than 10,000 people in 52 locations around the world.(5) When the results from all locations were pooled, systolic blood pressures were higher in people who ate more salt and less potassium.

* Clinical trials. In the Trials of Hypertension Prevention, a low-sodium diet lowered blood pressure significantly.(2) Potassium supplements didn't. But, says Whelton, "we've had tantalizing results from small studies, especially in African-Americans," who may stand to gain more because they typically consume less potassium.

"If people start out with a moderate or high intake, adding potassium may not accomplish much," says Harvard's Frank Sacks.

"High" is 4,000 to 4,500 mg of potassium a day, he adds. "Low" is 2,500 mg or less. Your best source: fruits and vegetables, which may work better than supplements. In fact, a 20-year study of middle-aged men found that those who ate more fruits and vegetables had a lower risk of stroke, even though they didn't always have lower blood pressures.(6)

"When we looked at the Nurses' Health Study to see who wasn't eating much potassium," adds Sacks, "we found people who were eating a junkfood diet."

Other eating changes may turn out to prevent high blood pressure (see "What's Not Proven"). Meanwhile, it's good to know that you can do something now to keep your pressure from ever rising (see "The Bottom Line").

"If we wait for people to get hypertension and then try to find, evaluate, and treat them, we're never going to end the problem," says Jeremiah Stamler. "It's true for every epidemic. When we vaccinated for polio, we ended the problem. When we improved diets to prevent rickets and scurvy, we ended the problem. The only way to end the problem of hypertension is to prevent it."

(1)Hypertension 25: 305, 1995.

(2)Journal of the American Medical Association 267: 1213, 1992.

(3)Archives of Internal Medicine 153: 186, 1993.

(4)Journal of Hypertension 5 (Suppl.): S205, 1986.

(5)Hypertension 14: 570, 1989.

(6)Journal of the American Medical Association 273: 1113, 1995.

RELATED ARTICLE: IS CUTTING SALT DANGEROUS?

How could it be? Cutting salt cuts blood pressure, and cutting blood pressure cuts heart attacks. Yet in June, the media reported--to a thoroughly confused public--that low-salt diets raise the risk of heart disease.

Michael Alderman of the Albert Einstein College of Medicine in New York studied nearly 3,000 men and women who were taking drugs to lower blood pressure.(1) The men who consumed less than 2,000 mg of sodium a day--as measured in their urine--had a higher risk of heart attacks.

But no one is ready to give people advice based on one study with so many holes.

The biggest: it failed to ask how often the men drank alcohol and smoked cigarettes. "It's possible that the men at the lower end of sodium excretion were heavy drinkers," says the National Heart, Lung and Blood Institute's Jeffrey Cutler. "And people who are heavy drinkers are also heavier smokers." Both have higher risks of heart attack.

"This hasn't changed the National High Blood Pressure Education Program's advice to eat less salt," he adds. "Until we know more, the public should ignore this study. The results are likely to be spurious."

(1)Hypertension 25: 1144, 1153, 1995.

RELATED ARTICLE: What's Not Proven

While some of these blood-pressure-lowering strategies hold promise, they're still unproven:

* Stress management. Many people assume that "hypertension" is something that happens to people who are very tense. In fact, the "tension" refers to the "stiffness" of your blood vessels, not your state of mind.

Nevertheless, intense short-term stress does raise blood pressure. But so far, stress management techniques like relaxation, meditation, and biofeedback have had inconsistent results on people with high blood pressure, and no effect on people with above-optimal blood pressure.(1)(2)

"While it may be desireable, stress reduction doesn't reduce blood pressure across the board," says Johns Hopkins's Paul Whelton.

* Magnesium. Hard water has more magnesium than soft water. And heart attacks and strokes are less common in areas that have hard water.

But research on people with high blood pressure has been disappointing. And in the Trials of Hypertension Prevention, supplements containing 340 mg of magnesium a day didn't work in people whose blood pressure was on the verge of "high."(2) It did cause an increase in diarrhea and loose or frequent stools, though.

"The better the studies, the clearer it's become that magnesium--at least in supplements--has no effect on blood pressure," says Harvard's Frank Sacks.

* Calcium. The National Heart, Lung and Blood Institute's Jeffrey Cutler has reviewed dozens of studies on calcium's ability to lower blood pressure.(3) "The bottom line is that in some studies there is an effect, but it's quite small...and that's with big doses."

"Big" means 1,000 to 2,000 milligrams of calcium a day. "Without pills," he adds, "most people aren't going to increase intake by more than 1,000 mg a day."

* Fish oil. "It's too early to recommend fish oil," says Frank Sacks. He reviewed a number of studies that tested fish oil on people with high blood pressure.(1)

"It lowered blood pressure, but only at high doses," he explains. "That's about six grams of omega-3 fatty acids, or 12 to 18 capsules of fish oil, a day." It's also equal to about four servings of fish.

In the Trials of Hypertension Prevention, half that amount of fish oil didn't lower blood pressure, but it did cause belching and unpleasant taste in a third to a half of the fish-oil-takers.

* Fats, protein, carbohydrates, and fiber. Around the world, populations that eat diets based on grains, fruits, and vegetables--that includes vegetarians in the U.S.--have lower blood pressures. Why?

Researchers don't know. They've lowered the fat intakes of people with high blood pressure. They've raised the monounsaturated fats. They've cut the protein. They've upped the fiber. The results: zippo.

But when Northwestern University's Jeremiah Stamler looked at the INTERSALT study, he saw lower pressures in people who ate more protein. That led Harvard's Frank Sacks to look at the Nurses' Health Study.

"Blood pressure was lower in women eating more low-fat dairy products, fish, and chicken, which are high in protein," says Sacks. "They were also eating more fruits and vegetables, and less fat and saturated fat--what we call a healthy diet."

Taking a cue from those findings, a new study--the Dietary Approaches to Stop Hypertension trial (DASH)--is comparing blood pressures in 456 people who'll be fed one of three diets for two months(4):

* an "average" American diet with refined grains, sugar, meats, and dairy fat (that means low potassium, magnesium, fiber, and calcium),

* a "fruits and vegetables" diet that's loaded with potassium, magnesium, and fiber (but that's not low in fat, sodium, and cholesterol), or

* a "combination" diet that's rich in low-fat dairy products, chicken, fish, lean meats, whole grains, beans, fruits, and vegetables (that means it's high in potassium, magnesium, and fiber, plus calcium and protein).

"We want to know if foods that contain potassium, magnesium, or calcium are different than supplements," says Cutler.

He and others are impressed by a recent study on 100 hypertensive men and women in the Netherlands.(5) Instead of ordinary salt, the foods they ate were made with a high-potassium, lower-sodium "salt" plus a little extra magnesium. After six months, average blood pressures fell by a striking 7.6 over 3.3 points.

"One of our motivations is to find out if the combination has a more-significant effect," says Cutler.

(1)Archives of Internal Medicine 153: 186, 1993.

(2)Journal of the American Medical Association 267: 1213, 1992.

(3)American Journal of Hypertension 3: 137S, 1990.

(4)Annals of Epidemiology 5: 108, 1995.

(5)British Medical Journal 309: 436, 1994.

RELATED ARTICLE: THE BOTTOM LINE

These tips are for everyone. If your blood pressure is low, they'll help keep it from climbing as you get older. If your blood pressure is already high, they may enable you to use less--or get off--medication.

* Lose weight if you're overweight. Dropping as little as ten pounds can make a difference.

* Cut sodium to no more than about 2,400 mg a day, and preferably 1,800 mg. High-sodium foods don't always taste salty. Check labels for the lowest-sodium brands. Avoid foods that supply more than 480 mg of sodium per serving. That's 20 percent of the Daily Value.

* Walk briskly, jog, swim, cycle, or do other aerobic exercise for 30 to 45 minutes a day at least three times a week.

* If you drink, keep it to no more than two servings of beer, wine, or liquor a day.

* Eat at least five to nine servings of fruits and vegetables a day. That should give you a hefty dose of potassium and lower your risk of cancer at the same time.

* Some people have high blood pressure only at the doctor's office. If you think you're one of them, buy a reliable device to measure your blood pressure at home. (See Consumer Reports, May 1992.)

* For more information on high blood pressure, call the government's hotline at 1-800-575-WELL.

RELATED ARTICLE: Should Women Drink?

Do women who drink have a lower risk of dying than women who don't? Yes, but only if it's not more than two drinks a day and only if they start out with an increased risk of heart disease, says a new study from Harvard Medical School.

Charles Fuchs examined the drinking habits of more than 85,000 nurses who were 34 to 59 years old when they first filled out diet questionnaires in 1980. After 12 years, he found that, compared to nondrinkers, the risk of dying was:

* 17 percent lower in light drinkers (one to three drinks a week),

* 12 percent lower in moderate drinkers (roughly four drinks a week to two drinks a day), and

* 19 percent higher in heavy drinkers (more than two drinks a day), often because they died of breast cancer.

But drinking was only linked to a lower risk of dying in women who were 50 or older and who had at least one of these risk factors for heart disease: high blood pressure, smoking, high cholesterol, diabetes, obesity, or a parent who had a heart attack before the age of 60.

"If you drink, it's okay in moderation--women who drank one to three drinks a week had the lowest risk," says Fuchs. "But don't start drinking just to live longer.

"There are better ways to get rid of risk factors for heart disease, like exercising, not smoking, or lowering your cholesterol. Unlike drinking, they have no downside."

Bonnie Liebman

New England Journal of Medicine 332: 1245, 1995.

RELATED ARTICLE: Protecting Your Prostate

Alcohol. Beta-carotene. Calcium. Exercise and weight. Fat. Fruits & vegetables. Saturated fat. Selenium. Vitamins A, C, D, or E. Only one of these suspected risk factors or protectors was consistently linked to the risk of prostate cancer in a new study from the Stanford University School of Medicine.

Alice Whittemore and colleagues collected diet information from 1,655 white, African-American, Chinese-American, and Japanese-American men with prostate cancer and 1,645 similar healthy men.

The result: Men who consumed more than 30 grams of saturated fat a day--mostly from meat and dairy products--had roughly twice the risk of advanced prostate cancer than did men who ate less than 11 grams of sat fat a day. No other diet, supplement, or exercise regimen seemed to matter.

"The evidence is mounting that saturated fat increases the risk of prostate cancer," says Whittemore. Her advice: shoot for 10 grams or less of sat fat a day.

BL

Journal of the National Cancer Institute 87: 652, 1995.

RELATED ARTICLE: How Much is Enough?

If you exercise for 30 minutes a day, does it matter if you work up a sweat or not? It may, say researchers from the Harvard School of Public Health.

I-Min Lee and co-workers studied the exercise habits reported in 1962, 1966, or 1977 by more than 17,000 men who were Harvard undergraduates between 1916 and 1950. By 1988, 3,728 of the men had died.

Lee's results: Only "vigorous" exercise was linked to a lower risk of dying. That includes bicycling, running or jogging, swimming laps, playing tennis, shoveling snow, or brisk walking (four to five miles an hour). Slower walking, gardening, golf, or light housecleaning didn't seem to help.

Men who expended at least 1,500 calories a week in vigorous exercise were 13 to 25 percent less likely to die during the study than men who expended less than 150 calories a week in vigorous exercise.

How does that square with other studies showing that less-strenuous activity lowers insulin, blood pressure, and cholesterol, and improves psychological well-being?

"It's not likely that moderate-intensity exercise is helpful with those endpoints but doesn't lower your risk of dying," says Lee.

Faulty memory may better explain the contradiction. "Vigorous activity is more likely to be accurately reported because people may remember when they go to the gym but not when they putter around the house."

Until more studies are done, Lee's advice: "Some exercise is better than none, and more is better than some."

BL

Journal of the American Medical Association 273: 1179, 1995.

RELATED ARTICLE: Nibbles

* In a small study, the cyanocobalamin form of vitamin B-12 failed to alleviate depression caused by winter seasonal affective disorder (SAD), as earlier reports had suggested.

BL

Journal of Affective Disorders 32: 197, 1994.

* After three years, a lower-fat diet reduced blood cholesterol in 334 eight- to ten-year-olds without impairing their growth, iron stores, or psychological well-being.

BL

Journal of the American Medical Association 273: 1429, 1995.

* Even short exercise programs (2 to 8 months)--especially those that improve balance, like Tai Chi--reduced the risk of falls in older people for two to four years after the programs began.

BL

Journal of the American Medical Association 273: 1341, 1381, 1995.