Easy does it!
Dec. 4, 2000 -- Chocolate doesn't tempt me. Sweets I can take or leave. But put a bowl of salty snacks in front of me and I'll polish them off in, well, two shakes of a saltshaker.
So it was bad news indeed when my doctor, frowning at my latest blood pressure numbers, said he thought I ought to go easy on salt. "Salt?" I asked, hoping maybe I'd heard him wrong.
"Salt," he said firmly, scribbling something in my chart. "Pretzels, chips, French fries, anything with added salt. Let's give it a try and see if we can get these numbers down a bit. Otherwise we may want to start you on a blood pressure medication."
Ouch. If anything could get me to swear off salty goodies, it's the threat of having to take a pill for the rest of my life. But can cutting down on salt really lower blood pressure?
For years, the advice on salt has flip-flopped. Some experts say too much can send blood pressure climbing. Others have said that for most people salt isn't a problem. Now, I learned, a landmark study promises to settle the debate.
A DASH of prevention
Since 1972, cutting back on salt has been a cornerstone of the National Blood Pressure Education Program. The advice is based on dozens of studies showing that high levels of salt are linked to hypertension. Most recently, in the February 2000 Journal of Cardiovascular Risk, British hypertension expert Malcolm Law concluded that reducing sodium intake could reduce blood pressure by an average of 10 points (10 mmHg) -- exactly how far mine needs to fall.
Not everyone has been convinced that Law's advice was good. In 1984, analyzing nutrition data gathered from around the country, researchers at the Oregon Health Sciences University in Portland found no evidence that dietary salt was linked to blood pressure. Four years later, results from 7,300 men enrolled in the Scottish Heart Health Study came to the same conclusion. The amount of salt they consumed had no effect on blood pressure.
Systolic pressure is the higher number, which measures the maximum pressure exerted when the heart contracts. Diastolic is the lower number, which measures the pressure when the heart is at rest. Normal systolic pressure is approximately 120 mmHg, and normal diastolic pressure is approximately 70 to 80 mmHg.
One thing has long been certain: High blood pressure is dangerous. In findings published this year in The New England Journal of Medicine, for instance, scientists followed the fate of 12,000 men between the ages of 40 and 59. Those with sustained increases of 10 mmHg in systolic blood pressure and 5 mmHg in diastolic blood pressure were 28% more likely to die of heart disease than those with normal readings.
Given that danger, the new findings from the Dietary Approaches to Stop Hypertension (DASH) program are encouraging. Back in 1997, researchers from the DASH study showed that healthy volunteers who ate a diet rich in fruits and vegetables, with low- or nonfat dairy products and only modest amounts of meat, were able to lower their blood pressure by a couple of points. Those with hypertension saw the numbers fall by as much as 11 points.
The original DASH study didn't measure sodium intake, however. So a new one, called DASH-Sodium, was begun. Four hundred twelve adults were randomly assigned to follow one of two diets -- the typical American diet or the lower-fat DASH diet, which emphasizes fruits and vegetables, whole grains, poultry, fish, nuts, and low-fat dairy products. During the first four weeks, the volunteers in both groups consumed 3,300 milligrams of sodium a day -- about the average for most Americans. Over the next four weeks, they cut back to 2,400 milligrams a day. For the last four weeks -- no pretzels, no chips, no ifs, ands, or buts -- they consumed only 1,500 milligrams of sodium.
The results, reported in May at the American Society of Hypertension Meeting, were a slam-dunk. The less salt the volunteers ate, the further their blood pressures fell. The biggest benefit showed up in people with hypertension. On the DASH diet with only 1,500 milligrams of salt, systolic blood pressure fell 11.5 points. Surprisingly, even people with so-called normal blood pressure were able to lower their numbers by more than seven points.
"The study shows how important it is to reduce sodium in the diet," says Eva Obarzanek, MD, a nutrition expert at the National Heart Lung and Blood Institute (NHLBI), who helped direct the DASH-Sodium trial. Claude Lenfant, MD, the director of the NHLBI, went even further when announcing the results. "These finding show that an intake below that now recommended could help many Americans prevent the blood pressure rises that now occur with advancing age."
The DASH-Sodium scientists aren't alone. The National Research Council of the National Academy of Sciences recently concluded that the ideal sodium level is around 1,800 milligrams a day -- roughly what the DASH study showed, and about half of what most of us now consume.
OK, I'm a believer. But shaking the salt habit, I've learned, isn't easy. True, using less salt in the kitchen hasn't been a big problem. By experimenting with other herbs and spices, I've found I can still give most of the dishes I love enough flavor to make them satisfying. (Heaven help us if pepper or oregano turns out to be bad for you, however.)
Of course, munching my way through a big bowl of salty snacks is out of the question. But I still treat myself to a couple of pretzel twists now and then. And I mean just a couple, now and then.
The real problem is prepared foods, which are loaded with salt -- and the only way you'd know it is to study the label. One brand of chicken vegetable soup on the market contains a whopping 2,398 milligrams of sodium per can, way over the healthy level. A single serving of a leading canned ravioli in tomato and meat sauce tips the scale at 1,173 mg. Grab a bacon-cheeseburger with fries at your local fast-food restaurant and you'll consume about 1,000 milligrams of sodium -- and that's before you reach for the salty french fries.
Luckily, there are low-salt soups and nuts out there, along with many other kinds of prepared foods. You just have to look carefully and study the labels. I've begun to take the time to cook my own meals more often -- not just because I can control how much salt they contain, but also because I usually can add an extra serving or two of vegetables. And hitting or exceeding the five-per-day mark for fruits and vegetables, the DASH findings showed, is as important as lowering salt intake, when it comes to keeping blood pressure levels in the healthy range.
It's working for me. Two months after banishing the saltshaker, my blood pressure has dropped back into the normal range. And this reformed saltoholic is determined to keep it that way.
Peter Jaret is a freelance writer in Petaluma, Calif., who has written for Health, Hippocrates, and many other national publications.
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