Has salt gotten a bad shake? Or should you still be trying to break the habit?

Q:

I'm pretty healthy. Do I really have to worry about how much salt I eat?

A:

Here's the dilemma: While many people are anti-salt because studies have linked it to elevated blood pressure--and thus to heart attacks and strokes--the salt industry vigorously contests this connection. And with some reason.

First, while reducing salt intake does make a blood pressure difference for some people, for many others it doesn't. Second, there's a dearth of evidence that high salt intake directly increases cardiovascular risk. "Only a single study has found an association in the general population between low-sodium diets and reduced incidence of stroke or heart attack, and that was in a Japanese population where 'low salt' individuals consumed more than the US average," claims Richard L. Hanneman, president of the Salt Institute in Alexandria, VA, an association of salt producers. He calls the current dietary advice "one size fits all" thinking.

Third, even hold-the-salt advocates acknowledge that salt seems to be a hypertension trigger only for a core group--not the entire population.

Q:

So who is most likely to benefit from a low-salt diet?

A:

In terms of hypertension, the answer is people who are salt-sensitive, meaning their bodies react to salt by shooting their blood pressure through the roof. Likely candidates for this group include African Americans, the elderly and anyone with a close relative who already has hypertension. Overall, an estimated 26 percent of Americans with normal blood pressure and 58 percent with hypertension are salt-sensitive, according to Myron Weinberger, MD, director of the Hypertension Research Center at the Indiana University School of Medicine in Indianapolis. Those people should absolutely keep their salt intake to no more than 2,400mg a day, Weinberger says.

Q:

But if my blood pressure's fine, can I stop worrying about salt?

A:

No, because high blood pressure isn't the only concern. Salt-loaded diets are also linked to fracture-prone bones and stomach cancer.

The bone connection is pretty straightforward: Excess salt ups the amount of calcium washed out in urine. The cancer connection is more indirect--put simply, diets high in dried, smoked, salted or pickled foods seem to contribute to stomach cancer in assorted ways, including by damaging cells lining the stomach. (Happily, diets high in fresh fruits and vegetables may protect against stomach cancer.) So even if your blood pressure's fine, overdoing salt is not.

Q:

Can a low-sodium diet benefit vegetarians?

A:

Possibly, especially if you eat a lot of processed and convenience foods and have a family history of high blood pressure. But in general, vegetarians are much less likely to have high blood pressure than meat eaters are, partly because they don't eat fat-laden meats, which contributes to high blood pressure, and often limit dairy products--which can thicken your blood and force your heart and blood vessels to work harder--and because plant foods are naturally low in sodium.

Q:

So how much salt is too much? And how much salt should I aim to take in daily?

A:

Almost all of us eat far more salt than we need (also called sodium; more on that in a bit). While your body can't live without sodium--it takes about 500mg daily for your nerves and muscles to work and for your fluids to stay in balance--most of us eat at least 10 times that, or 5,000mg daily. That's way too much to be healthy, according to the American Dietetic Association.

As for how much you should consume, it depends on who you ask, and on your race, age and health.

* Race: No more than 1,500mg (about 2/3 teaspoon) for African Americans or middle-aged and older adults, state the 2005

Dietary Guidelines for Americans.

* Age: Up to 2,300mg for young adults, add the Guidelines.

* Health: Just 1,500mg for healthy adults, says the Institute of Medicine of the National Academies.

* In general: Fewer than 2,400mg (about 1 teaspoon), according to the National Institutes of Health.

Overall, it seems that somewhere between half a teaspoon and one teaspoon a day is a sane range.

Q:

Can I take in too little sodium?

A:

Since we can get by with as little as 500mg sodium daily, you'd be hard-pressed to underdo. But it is possible to lose the sodium that's already in us. Prolonged heavy sweating, drinking much too much water--which sometimes happens to marathon runners--and chronic diarrhea can all cause internal sodium levels to drop. The result can be dizziness, confusion, muscle cramps, and, in extreme cases, seizures, coma, even death.

Q:

Why is sodium/salt added to so many foods? And what's the difference between the two?

A:

Well, people love the taste of it for one thing. It also keeps food from spoiling, improves the texture of processed foods and helps control fermentation in bread and cheese.

We tend to use "sodium" and "salt" interchangeably, but they're not the same. Sodium is actually a component of salt, which is made of roughly 40 percent sodium and 60 percent chloride. (Salt's chemical name is sodium chloride.)