For years we’ve
been warned to shake the salt habit—or risk serious harm to our health. Now,
two new studies show that low-sodium diets may not protect heart health—and
could even raise the threat of fatal
heart attacks and strokes. Meanwhile, dozens of public health groups, including
the Institute of Medicine (IOM), are demanding that the FDA force food
manufacturers to reduce the amount of sodium in prepared and processed foods,
which the Center for Science in the Public Interest has called salt “the deadliest ingredient in the
Is salt a
dietary serial killer or not? Some sodium is essential for our bodies to
function, since it helps maintain the right fluid balance and plays a key role
in nerve and muscle function. However, 90
percent of Americans eat too much salt, according to the CDC. Here’s a look
at the latest science—and grains of truth to help you make smart decisions
about healthy eating.
What’s the theory behind salt restriction? Groups
like the National Heart, Lung and Blood Institute, the National High Blood
Pressure Education Program, and the government’s new Million Hearts, campaign
(aimed at preventing one million heart attacks and strokes over the next 5
years) consider reducing salt consumption a smart public policy to decrease
high blood pressure, a major risk factor for heart attacks and strokes. Last year, a
National Institutes of Health-funded study reported that lowering salt
intake by just 3 grams (about half a teaspoon) a day could prevent up to 92,000
deaths a year—as well as 100,000 heart attacks and 66,000 strokes.
What’s the downside of cutting back on
salt? Two new studies found these potential hazards of reducing salt:
A rise in
heart-harming blood fats: In November, a
Cochrane review of 167 studies found that when people with normal or high
blood pressure were randomly assigned to high-salt or low-sodium diets, those
who ate less than 2,800 milligrams of sodium had a very modest drop in blood
pressure, while levels of harmful blood fats (cholesterol and triglycerides)
actually rose, compared to people who ate more than 3,450 milligrams of sodium
(about the amount the average American eats daily, according to the CDC).
rate of heart attack and stroke deaths. A studypublished in Journal of the
American Medical Association in May involving 3,681 middle-aged men and
women who were initially free of heart disease or high blood pressure
(hypertension) found that those who ate the least salt (measured by the amount
of sodium in their urine) had a 56 percent higher risk of dying from a heart
attack or stroke than those who ate the mostt, even when obesity, smoking and
diabetes were taken into account.
How scientific are these studies? Although
Cochrane and JAMA are among the world’s most respected publications, critics
charge that both studies were flawed. The Cochrane review was attacked for
giving too much weight to short-term studies that may not reflect the long-term
impact of salt reduction, while CDC officials charge that the JAMA study was faulty because the
participants were relatively young (with an average age of 40 at the start of
the study) and not that many of them died during the nearly 8 years of
follow-up. There’s also debate whether urine tests are the best way to tell how
much salt people eat.
Does salt affect everybody the same way? No.
10 to 20 percent of people appear to be “salt sensitive,” meaning that they
tend to retain sodium, leading to fluid retention and increased blood pressure.
Those at greatest risk include African-Americans, older people, and people who
already have high blood pressure.
What’s the bottom line? Everybody needs
some sodium, because it helps the body maintain a healthy fluid balance and
plays a vital role in nerve and muscle function. The CDC recommends consuming
less than 2,300 milligrams per day if you don’t have high blood pressure, and
1,500 mg if you do. Also follow these heart-smart tips
salt sensitivity. Use a home blood pressure monitor (available for as
little as $20 at drugstores) to get a few baseline readings, then cut down on
salt for a month. If your blood pressure drops, it’s likely that you are
salt-sensitive and therefore would benefit from a low-salt diet (1,500 mg.
Eat Mediterranean-style. Focusing on fresh fruits, vegetables,
whole grains, fish and heart-healthy oils enhances heart health and lowers
sodium. About 90 percent of the salt in the typical American diet comes from
processed and restaurant foods—not the salt we sprinkle on food prepared at
30 minutes a day. Taking a daily brisk walk, biking, or jogging can cut
your risk for high blood pressure by about 40 percent—and also does your heart