Surviving the Salt Shake-Up

The tactic of avoiding salty foods to keep your blood pressure low isn't a safe bet anymore. Here's what is

Coaxing Americans to go easy on salt is like asking fish to give up water-we're all swimming in it. Take the ham-and-Swiss you had for lunch. You can't actually see the salt, not the way you can see the crystals on a pretzel. But it's there-in the bread, in the cheese, in the ham. It's in the mayonnaise and the mustard. That pickle slice on the side is saltiest of all--not to mention those potato chips.

Unless you ate your napkin, everything that came near your lips at lunchtime was laced with salt--so much, in fact, that you've already exceeded the amount that experts say you should eat in an entire day.

Never mind the breakfast cereal you had this morning (some brands have more salt per serving than potato chips do) or the blueberry muffin you snagged for a snack (more salt than two cups of microwave popcorn). Even health experts admit that the only way to lower salt to the recommended daily dose--a bit more than a single teaspoon--is to steer clear of practically all ready-made foods and cook every meal at home.

But here's the real shocker: There may be no good reason for everyone to struggle to avoid salt. In fact, cutting back too much might even kill you.

According to a study published recently in the journal Hypertension, men with high blood pressure who held their salt to about half the daily maximum had four times as many heart attacks as did hypertensive men who ate three times as much salt.

Amazingly, though the link between salt and blood pressure has been investigated for decades, no study until this one had ever tracked heart attack rates in people on a low-salt diet. The conventional wisdom among physicians has long been that the best advice for patients with high blood pressure is to cut back on salt--or more precisely, sodium, the chemical that joins with chlorine to form a grain of salt. (That tea-spoon-plus of salt works out to 2,400 milligrams of sodium, all you're advised to get in a day.)

Sodium can exert a powerful influence on the body's circulatory system. Blood vessels, like intelligent garden hoses, have the ability to adjust their diameter to regulate blood flow. According to one theory, the problem with sodium is that in some people it prevents the vessels from opening fully. The heart works harder to pump blood through these slimmer tubes, and the pressure goes up. Left unchecked, that extra pressure pummels the heart, kidneys, and blood vessels, leading all too often to heart attacks and strokes, kidney problems, and eye damage.

Because worst-case scenarios don't get much worse than that, health officials have traditionally argued that even people with normal blood pressure should shake the salt habit. A low-salt diet seemed so obviously beneficial that nobody had looked at whether it might be harmful.

"Yet that's what we should really care about-do people live or die?" says Michael Alderman, a blood pressure researcher at Albert Einstein College of Medicine, in New York, who's president-elect of the American Society of Hypertension and coauthor of the study.

"To ask Americans to turn their diets upside down in the hope that a low-salt diet will translate into health benefits strikes me as faith worthy of the church fathers," Alderman says. "I'd like to see some data that such a procedure would be both safe and beneficial. In God we trust--all others show data."

Looking for evidence, Alderman and his team gauged the salt intake of nearly 3,000 men and women with high blood pressure and then tracked their health--"counting the dead ones," as Alderman puts it. About four years and 58 heart attacks later, the researchers crunched the numbers and came up with a conclusion that sent an audible buzz through the medical community: The group of men who ate the least salt had the most heart attacks. The scientists might just as well have announced that gravity makes objects fall up.

For Alderman, the study confirmed his view that tinkering with a person's diet can trigger profound physiological changes. Cutting back on salt, it turns out, prompts the kidneys to crank out renin, a powerful' hormone that constricts blood vessels. Because renin is also known to swell cells lining small arteries, including those in the heart, Alderman had long suspected that a low-sodium diet could incite heart attacks among hypertensive patients. His results suggest it very well might.

"For people with atherosclerosis," Alderman says, "a little extra renin may be the little extra that does them in."

Alderman is quick to warn that his findings shed light only on salt's effect on hypertensive men (the women in the study had too few heart attacks to permit any valid conclusions). The findings might well be different, he says, for women and for people with normal blood pressure. Still, he's concerned.

"As a wholesale prescription for people being treated for hypertension," Alderman says, "a low-sodium diet doesn't look like a good idea." And for the restor us? "My advice would be my mother's," he says. "All things in moderation."

He's hardly the only iconoclast. At Oregon Health Sciences University, in Portland, David McCarron, a professor of medicine, contends that our diet may indeed promote high blood pressure, but not because we eat too much salt. Instead, says McCarron, the problem stems from our not getting enough calcium, potassium, and magnesium.

"If you have enough of these other minerals, staying on a normal sodium diet actually gives you the lowest blood pressure," he says. "Restricting your sodium intake appears to somehow impair the ability of these other minerals to keep your blood pressure low."

How much salt does McCarron consider normal? "If people are eating a balanced diet," he says, "they should just follow their instincts."

Not surprisingly, most mainstream health experts disagree. "We have the massive accumulation of 50 years of data on the relationship between salt intake and blood pressure and the havoc that higher average blood pressure wreaks in the United States," says Jeffrey Cutler, director of the clinical applications and prevention program at the National Heart, Lung, and Blood Institute. "I don't think we can say with a great degree of certainty what the optimally low sodium intake should be, but we can say that the vast majority of people eat far too much salt."

That's around two teaspoons a day, on average. Cutler and other experts would like to see us get down to one-or less.

"Sodium is definitely related to blood pressure, not only in those who have high blood pressure but even in individuals with normal levels," says Alicia Moag-Stahlberg, a research nutritionist at Northwestern University Medical School and a spokeswoman for the American Dietetic Association. "I don't know why people have gone back and forth on the sodium issue," she says.

Blessedly, once you move away from the unreconciled salt issue, all the experts about what else people can do to keep thee blood pressure in check:

Get all the minerals you need. A national committee on the treatment of high blood pressure now agrees that getting enough calcium, magnesium, and potassium is essential. "It's almost a no-brainer," says McCarron. "You just have to eat three or four servings of fruits and vegetables each day, which means a salad at lunch and dinner and a piece of fruit in the morning and later as a snack. If you also have three glasses of skim milk, you're there."

If that seems like a lot of milk, you can also get calcium from dark green leafy vegetables--spinach, turnip greens, collard greens-and from corn tortillas and sardines. For magnesium, count on those same leafy greens, as well as whole grains, nuts, and dry peas and beans. For potassium, try bananas, potatoes, dairy products, avocados, figs, dates, fish (especially tuna and salmon), mushrooms, tomatoes, winter squash, sweet potatoes, and lean pork.

Lose some weight. Overweight people have up to six times the hypertension risk of their slimmer counterparts. Dropping even a couple of pounds can knock several points off your blood pressure. "With a ten-pound loss, you're going to have even more of a benefit," says Moag-Stahlberg.

Get moving. Even if you don't need to trim down, regular exercise will help. As little as 30 minutes of brisk walking every other day has been shown to lower the blood pressure of hypertensive patients by about ten points. Researchers have observed that sedentary people run an up to 50 percent higher chance of developing high blood pressure than do their active peers.

Watch the wine and beer. Just one or two drinks a day can substantially raise your blood pressure--to the point of wiping out the benefits of blood pressure medicine. Binge drinking is even worse.

Do all that first, and you might actually be able to ignore salt--at least, that's what the revisionists argue. That said, your doctor may still have valid reasons for ordering you to cut back. A low-salt diet makes sense for patients with congestire heart failure or kidney ailments-conditions worsened by salt's tendency to make the body retain fluid.

But if high blood pressure is the prime concern and your physician insists you cut back on salt, make sure you get more than a pep talk. Ask to be paired up with a nutritionist who can evaluate your eating habits, steer you to low-sodium foods, and conduct regular blood pressure checkups.

Without that diet monitoring, you may think you've cut back when you really haven't. Seventy-five percent of the sodium Americans eat comes from cheese, canned soups, packaged dinners, snack crackers, and other processed foods, not from our own salt shakers.

The blood pressure checks are also key. Strange as it may sound, some people who cut back on salt actually see their blood pressure rise. This could be that old devil renin again, constricting the blood vessels.

The moral is that the only sodium advice that really makes sense is the kind tailored to your body by the person who knows it best-your doctor. As for that general go-easy command we've all heard so often? Take it with a grain of salt.




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