Study Questions Salt’s Link With Hypertension

About a fourth of the supermarket shoppers queried for the 1989 Food Marketing Institute’s Consumer Attitudes and the Supermarket survey indicated that the salt content of the foods they purchase was a concern. The correlation between high salt intake and hypertension is an obvious element in this opinion.

The remainder of the U.S. population has had a difficult time giving up the crystal, regardless of the health risk. The complaint is that the mineral contributes much of the palatability to food that Western civilization is accustomed to.

While the effects of a high sodium intake on the body are still being studied, some scientists in the field have begun questioning the previously held position that links salt, hypertension and cardiovascular disease. New research, such as last summer’s Intersalt, has only clouded the already convoluted issue.

Reason to Be Concerned

There is, of course, reason to be concerned about high blood pressure. Higher blood pressure results when the heart is working harder than normal or when the arteries are under strain. When the heart is forced to work under these conditions for an extended time, it tends to enlarge. Stressed arteries can become scarred, hardened and less elastic, which prevents them from supplying the normal amount of blood the body needs to function properly. These types of prolonged stress can result in heart attack, stroke or atherosclerosis (hardening of the arteries).

An elevated blood pressure may develop from a number of causes--most of which are not clear--although obesity, alcohol and tobacco use are known risk factors. (In at least 10% of the cases, hypertension may be a symptom of an underlying problem such as kidney abnormality, a tumor of the adrenal gland or a genital defect of the aorta.)

But a high intake of salt, the most widely publicized contributor to high blood pressure, has been scrutinized recently by some researchers who complain that the salt scare has gone far beyond the data.

“The salt story has changed dramatically in the past five years since Time (magazine) said salt is evil,” said Dr. David A. McCarron, professor of medicine and director of the Institute for Nutrition and Cardiovascular Research at the Oregon Health Sciences University, Portland, during a food media conference here earlier this year.

Belief Challenged

He explained that a growing number of hypertension authorities are challenging the belief that dietary salt intake can cause high blood pressure in the general population, as well as the attitude that restriction of sodium in the diet carries no risk. He said that he would like to see more emphasis placed on the other confirmed risk factors: obesity, excessive alcohol consumption and smoking.

In his discussion, McCarron pointed out that the results of Intersalt, a widely publicized international research project that were reported last summer in the British Medical Journal, were complex, but they did indicate that salt is only a minor factor in the development of hypertension, when salt consumption exceeds a very low level.

The Intersalt Cooperative Research Group consisted of scientists from 32 countries who had assembled one or more groups of 200 participants between the ages of 20 and 59. After careful scrutiny of urinary sodium excretion samples from more than 10,000 men and women, Intersalt investigators concluded that the presence of dietary sodium wasn’t related to the prevalence of high blood pressure. Although there was a significant relationship between sodium intake and change in blood pressure as a person aged, body mass index and the presence of alcohol were seen to be much stronger predictors of blood pressure status, McCarron said.

This data supports McCarron’s belief that sodium restriction should be relatively low on the list of health priorities for some, if not most, Americans.

“If we are to properly inform the public,” he said, “we must emphasize the areas of life style and nutrition that (we agree possess) the potential to significantly lower the blood presure of society. We should be stressing weight control, routine exercise, elimination of excessive alcohol consumption and abstinence from tobacco.”

There are other noted medical researchers who agree with McCarron’s assessment of the Intersalt data. Dr. Harriet Dustan, emeritus professor of medicine and director of the cardiovascular research and training center at the University of Alabama at Birmingham, reports that since the relationship between salt and blood pressure is complicated and not a direct correlation, there is little need for discretionary salt use by everyone. She too believes that there are other factors that influence blood pressure more than sodium does.

“We do not know enough yet about the multiplicity of factors that influence the pressor effect of salt to prescribe salt restriction for everybody,” Dustan said in an article in a medical publication following Intersalt.

“There is no denying that salt intake is important to the development of hypertension,” but I don’t think it is for everybody,” she said.

But the sodium-hypertension link is not without adversaries.

Norman Kaplan, head of the Hypertension Section at the University of Texas Southwestern Medical School, explained why it is important even for those with a normal or low blood pressure to worry about sodium, despite the Intersalt study conclusions.

No Way to Know for Sure

He explained that within the general population at least one in five people will develop hypertension during their lifetimes, leaving four who theoretically don’t have to worry. But among those who do become hypertensive, there is no way to know for sure which ones are salt sensitive and which ones are not, since there is no established protocol that determines sodium sensitivity.

“Lacking that knowledge,” Kaplan said, “the simplest thing is that we all cut down on salt.”

He recommends making modest changes such as reducing the intake of processed foods such as corned beef and pickles and opting for fresh foods of any sort and low-salt alternatives to canned items and dairy products.

“I don’t think it hurts any of us . . . as we grow older we tend to get a rise in blood pressure, particularly the systolic, and Intersalt did show that that is lessened with a lower sodium intake.

“In people with high blood pressure at least half of them have shown some effect (of a low-sodium diet). There are no side effects and most people don’t miss the extra salt. It (the high-sodium/hypertension connection) has never been proved, but we hope it will reduce the likelihood of people getting hypertension and not harm anyone.”

While doctors and researchers don’t agree on a safe amount of sodium in the diet--a “safe and adequate” daily intake of 1,100 to 3,300 milligrams has been set by the National Research Council of the National Academy of Sciences. The current national consumption is at least twice that amount, according the the American Heart Assn. (2,000 milligrams is equivalent to about one teaspoon.)

Whether or not high salt intake causes high blood pressure is debatable. So until an accord can be reached, experiment with recipes such as those that follow. They rebuke the “less salt, less flavor” notion and take advantage of fresh herbs and wholesome ingredients for flavor.

Keep in mind that convenience foods, such as canned goods, frozen items and baked products, sausages, luncheon meats and some desserts can vary in the amount of sodium they contain. Read labels carefully.

A fresh tomato, for example, contains as little as 14 milligrams of sodium, but one cup of canned tomato soup, prepared with an equal amount of water, has about 932 milligrams. A cup of commercial tomato sauce has 1,498.

SQUASH-SAGE BISQUE

1 (14 1/2-ounce) can less-salt chicken broth

2 small butternut squash, peeled and chopped

1 medium onion, chopped

1 medium apple, peeled and chopped

1/4 cup chopped fresh parsley

2 teaspoons minced fresh sage leaves

1 clove garlic, minced

1/2 cup milk

Sage leaves for garnish

Combine chicken broth, squash, onion, apple, parsley, 1 teaspoon sage and garlic in 2-quart saucepan. Bring to boil, then reduce heat to low and simmer, covered, 30 minutes or until vegetables are tender.

Place mixture in blender container and blend until smooth. Return to saucepan and add milk and remaining 1 teaspoon sage. Simmer over medium heat 5 minutes. Makes 4 servings, about 1 cup each.

QUICK CHICKEN SCALOPPINE

4 boneless, skinless chicken breast halves

3 tablespoons butter or margarine

1 tablespoon olive oil

1/4 cup white wine

1/3 cup half and half

2 tablespoons coarsely chopped fresh herbs such as basil, chervil, chives, baby dill, marjoram, rosemary, tarragon or thyme

1/8 teaspoon black pepper

Fresh herb sprigs

Place each chicken breast between 2 pieces plastic wrap on wood board. Pound to 1/4-inch thickness with meat mallet.

Melt butter and oil in skillet. Add flattened chicken pieces in single layer, browning quickly on both sides. Cook about 2 minutes or until no longer pink in center. Place cooked pieces on warm platter as done, keeping warm while making sauce.

In same skillet, bring wine to boil, scraping up browned bits in pan. Reduce heat and simmer 2 minutes. Stir in half and half, herbs and pepper. Cook 1 minute longer, then spoon over cooked chicken. Garnish with fresh herb sprigs. Makes 2 to 4 servings.

TOMATO-STUFFED TOMATOES

1 cup dried tomatoes

6 medium tomatoes or 4 medium green peppers

1 tablespoon oil

2 shallots, peeled and sliced

1 clove garlic, minced

1/2 cup cooked rice

1 tablespoon chopped fresh basil leaves or chives

1 teaspoon chopped fresh rosemary leaves

1/4 teaspoon black pepper

2 tablespoons grated Parmesan cheese

Blanch dried tomatoes in boiling water to cover 2 minutes. Drain well. Chop and reserve.

Cut thin slice from tops of tomatoes or stem end off green peppers. Scoop out pulp and seeds of tomatoes. Discard seeds and chop pulp. (Remove and discard seeds only from peppers.)

Heat oil in small skillet. Saute shallots and garlic 2 minutes. Stir in rice, basil, rosemary, pepper and rehydrated and chopped tomatoes. Cook until heated through. Spoon mixture equally into each tomato or pepper shell. Place in shallow baking pan and sprinkle with Parmesan cheese. Bake at 400 degrees 10 to 15 minutes. Makes 6 or 4 servings.

BULGUR WITH BASIL AND WALNUTS

2 tablespoons butter or margarine

1 medium onion, chopped

1 medium clove garlic, minced

1 (14 1/2-ounce) can less-salt chicken broth

2 tablespoons minced fresh basil leaves

1 1/4 cups bulgur wheat

1/3 cup chopped walnuts

1 tablespoon lemon juice

Melt butter in 2-quart saucepan over medium heat. Cook onion and garlic until onion is tender. Add broth and basil. Heat to boiling. Add bulgur, walnuts and lemon juice. Remove from heat, cover and let stand 20 minutes or until liquid is absorbed. Makes 6 servings.

PARMESAN-HERB POPOVERS

1 cup flour

1 cup milk

1 tablespoon melted butter or margarine

2 eggs

1/4 cup grated Parmesan cheese

1 tablespoon minced fresh dill weed

1 tablespoon minced fresh herbs, such as basil, chives, rosemary, sage, oregano, marjoram or tarragon

Spray 6 glass custard cups or muffin tins with nonstick vegetable spray. Place in oven to preheat.

Meanwhile, in deep mixing bowl, combine flour, milk, butter and eggs. Beat together lightly with wire whisk until well mixed. Stir in cheese, dill and desired herbs just until mixed. Remove pan from oven and pour batter into cups to fill 1/2 to 2/3 full.

Bake at 450 degrees 15 minutes, then reduce heat to 350 degrees and bake 15 minutes longer or until popovers are firm and golden. Carefully remove from pan and make few slits in bottom of each with tip of knife to remove steam. Serve hot. Makes 6 servings.