The new science of eating to...control blood pressure

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If you have high blood pressure (defined as a reading of 140/90 and above), you want powerful medicine to control it. And--as study after study has shown--diet is powerful medicine. It can't always replace pills and other medical means when blood pressure is elevated, but it often does. And it can frequently either boost the effect of medication or allow for a lower dose. More good news: Those who are most helped by good eating are the ones who most need help. The higher your blood pressure, the more it is likely to fall if you use your head when you fill your belly.

Diet therapy to reduce high blood pressure calls for the following:

An eating plan geared to weight control. For those people who are overweight, a low-fat (made up of less than 20 percent of calories) diet, high in unrefined complex carbohydrates is ideal. (See "Burn Fat, Peel Pounds" on page 66.)
Limiting sodium intake to 2,400 milligrams a day (the amount in a level teaspoon of table salt). Discuss with your physician whether it would be wise to limit your sodium intake even more.
Including in your diet a variety of fruits and vegetables that together provide at least 3,500 mg. of potassium a day.
Getting your Daily Value for magnesium and calcium. (See the article "Fend Off Fractures" on page 81.)
A GRAIN OF SALT
Being "sodium sensitive" means that your blood pressure rises in in the hypertension division at the University of Texas Southwestern Medical School in Dallas, "It's like height or any other biological phenomenon. It varies a great deal among individuals. Some people are exquisitely sensitive. If they touch salt, their blood pressure goes way up. For a few others, their intake hardly seems to matter."

About half of people with high blood pressure fit into the category of highly sodium sensitive. For many of these people, sodium restriction is definitely a good idea* Among those people who are not salt-sensitive, restricting salt too much--to less than half a teaspoon a day--also may raise their blood pressure. So if you happen to be hypertensive, what should you do?

The best approach is to start by making sure that you get no more sodium than your body needs. The average American consumes about 4,000 rag. of sodium each day. That's quite a few shakes beyond the 2,400 rag. the National Academy of Sciences suggests as a maximum intake for just about everyone. A level teaspoon of salt contains about 2,400 milligrams of sodium, so if your current intake is 3,500 mg. or less, you can get yourself to the adequate-intake zone by getting rid of about half a teaspoon of salt each day.

The next step is to check with your doctor to see if you might benefit from further cuts in sodium intake. There's currently no standard test to determine if you're sodium sensitive--or if your blood pressure might rise due to serious sodium restriction. But you and your doctor may be able to determine if you're sensitive to sodium through dietary trial and error. Harvey B. Simon, M.D., professor of preventive cardiology at Harvard Medical School and a founding member of the Harvard Cardiovascular Health Center, and author of Conquering Heart Disease (Little, Brown & Company, 1994), suggests cutting sodium intake to 2,000 mg. a day for six weeks. If your blood pressure goes down, that's a strong indication that you're salt sensitive. So if some form of sodium restriction is your objective, what's a good plan of attack?

Cut back on the saltshaker first. "That's what we go after," says Dr. Kaplan. "Salt poured on food is the thing people have the most immediate control over."

Then go after the foods Dr. Kaplan calls "salt mines," for example, anchovies, sauerkraut, pickles and salami. "All we're talking about here is taking a few of life's pleasures away," says Dr. Kaplan. "It won't be easy for those few people who are addicted to salami. But it's usually not a major sacrifice."

The greatest salt mine may be potato chips. "You'd need to eat 10 whole potatoes to get the amount of sodium in just 10 potato chips," says Dr. Simon.

The next sodium source on your list should be processed foods because salt and other sodium compounds act as preservatives and flavor enhancers and are often used liberally in them. Not surprisingly, processed foods (which include some of the worst salt mines already mentioned) are far and away the biggest source of sodium in the American diet, perhaps accounting for more than 70 percent of our intake. (By contrast, the sodium naturally present in foods accounts for about 12 percent.) Canned foods are the worst offenders. But you can find a high sodium content in some frozen foods, baked goods and many staples at fast-food restaurants. Reading food labels is critical to finding your way past the salt mines in the supermarket. (See "Label Shakeout" on page 91.)

How much of a difference does all this sodium-searching really make? Well, for many people, for each teaspoon of salt they eliminate, they can expect a five-point drop in systolic (top number) pressure and half that in diastolic (bottom number) pressure. For millions of Americans, this would be enough of a drop to eliminate the need for medications.

POTASSIUM POTENTIAL
Now we switch from what you need less of to what you need more of. "You can think of potassium as the opposite of sodium," says Dr. Simon. Just as a high sodium intake can raise blood pressure, so too can a low potassium intake, since potassium works as a blood-vessel dilator. But this doesn't mean huge amounts of potassium are needed.

The Daily Value for potassium is 3,500 mg., "but it's safe to consume substantially more than that," says Dr. Simon. The trick is getting enough potassium in your daily menu, without going on the chimpanzee diet. Actually, bananas are not the highest source of potassium, which can be found in a wide assortment of fruits and vegetables. And there are some surprisingly rich sources. (See "Potassium-Packed Foods" on page 91.)

One caution: If you're taking a potassium-sparing diuretic, which causes the kidneys to hoard the mineral, you should not increase your potassium intake without discussing with your doctor any changes you'd like to make.

CALCIUM AND MAGNESIUM CONNECTION
Along with potassium, you can add calcium and magnesium to the list of minerals that may help lower your blood pressure through some unknown ways. People with hypertension tend to have lower consumption of all three. African Americans seem to be especially vulnerable to low calcium intake.

As with potassium, you don't necessarily need these minerals by the shovelful. Instead, you simply need to be certain you're getting enough calcium (there are lots of tips in our article on page 81) and magnesium (see "Magnesium Sources" on page 154).

POTASSIUM-PACKED FOODS

Mg.

1/2 cup dried apricots 896
1/2 cup dried peaches 784
1 cup cooked plantain slices 716
1 cup plain lowfat yogurt 531
1 boiled potato, cooked in skin 515
3 ounces baked or broiled halibut 490
1/2 cup boiled lima beans 478
1 banana 451
1 boiled potato cooked without skin 443
1 sweet potato baked in skin 397
1/2 cup boiled baby lima beans 365
1/2 cup boiled kidney beans 355
1/2 cup All-Bran 340
1/2 cup canned kidney beans 329
1/2 cup winter squash, boiled, mashed 321

MAGNESIUM SOURCES

Mg.

1/2 cup 100% Bran 121
1/2 cup All-Bran 120
2 tablespoons dried pumpkin-seed kernels 92
1/2 cup wheat bran 86
1/2 cup boiled wax beans 65
2 tablespoons toasted wheat germ 45
1/2 cup Bran Chex 41
6 medium oysters, steamed 40
1/2 cup lima beans, boiled 40
1/2 cup Bran Buds 40
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by Steve Schwade with Linda Rao

SHAKING THE HABIT
If salt seems like something your taste buds just can't do without, consider this: Salt may actually hide flavor. And if you're absolutely convinced you're addicted to salt, you must know this: Tastes change.

"People who've cut down on Salt often find months after that salty food tastes terrible," says Harvey B. Simon, M.D., professor of preventive cardiology at Harvard Medical School, Cambridge, Massachusetts.

"After you shake the habit and discover the real taste of food, you don't want the taste covered up by salt. In fact, you feel terribly thirsty after eating salty food, and it's a very uncomfortable feeling."

Of course, you're wondering how to get to this wonderfully unsalted state of mind. Dr. Simon advises that you trick your taste buds by changing very gradually. "Begin by substituting low-sodium foods for the highly salted variety. They may seem bland at first, but in a little while, you'll actually start to like them. And besides the salt, you'll begin tasting the food.

"Next, wean yourself from the saltshaker. Measuring the amount of salt you're sprinkling over food will help you measure your progress, and it may surprise you to see just how much you've been adding.

"At the same time, begin eliminating the salt from your cooking. Look upon all this as a great opportunity to experiment with new flavors and seasonings. Your taste buds will love you," says Dr. Simon.

Some flavors may be particularly effective substitutes. "Sour flavors can mimic a salty flavor," says Beverly Cowart, Ph.D., clinic director at the Monell Chemical Senses Center in Philadelphia. "So some people tend to confuse salty with sour. Citric acid, sometimes called 'sour salt' and a component of lemon juice, is one example.

"There are some similarities in how salt and sour are perceived by the tongue. So some people may find lemon juice or vinegar to be acceptable alternatives to salt, providing a similar flavor." So salt lovers, be brave. Cutting back on salt isn't deprivation, but a gift to your taste buds!

SMELLING SALT
You need to know where salt is lurking. Because even though you can taste it, your tongue is no calculator: You may never suspect just how much salt you're getting.

LABEL SHAKEOUT
Uncle Sam has stepped in to bring order to the once chaotic world of food labels. Here's what those words mean:

Sodium free Less than 5 milligrams per serving. No need to restrict yourself, since 400 servings a day would still keep you at 2,000 mg. of sodium!

Very low sodium: Thirty-five mg. or less per serving. You're still in the safe zone.

Low sodium 140 mg. or less per serving. Don't get reckless. A few servings can add up in a hurry.

Reduced sodium Three-quarters less sodium than is typical for that food. Fact is, many foods are typically high in sodium, so reducing that amount may not be as helpful as you think.

Also, the container may not say simply "salt," but if it says any of these, you can bet it is salt Don't be fooled by:

* sea salt * garlic salt
* onion salt * seasoned salt
* brine
NOTE: If a serving size is very small, for example two tablespoons of salad dressing, then 35 to 140 mg. can still be quite a high concentration of sodium for such a small portion.

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