| Salt Assault
By: Maureen Callahan, M.S., R.D.
A Short History of Salt
As rocks go, it's not much to look at. But for much of history, dirty gray crystals
of salt made the world go round, as a flavoring, as a preservative, as money:
Roman legions were sometimes paid in chunks of the stuff.
Here in modern America, we're way overpaid. We eat nearly twice the sodium
we should, and we can do that without even touching the salt shaker. The sodium
hides in processed foods, put there by food companies to preserve products that
would otherwise go bad, or to make bland or bitter food taste better, or maybe
just to appeal to our craving for the stuff.
Earlier this year, the Institute of Medicine, which helps set government nutrition
recommendations, decided that people should try to take in about 1,500 milligrams
(mg) of sodium daily, with an upper limit of 2,300 mg. Before, they recommended
no more than 2,400 mg.
What, Me Worry?
It's more than the risk of high blood pressure and subsequent heart disease and
stroke that prompted Mom to hide the shaker from Dad 20 years ago. Excessive sodium
is now linked to other illnesses, such as cancer and kidney stones.
American men eat more than 4,000 mg sodium a day, and it's easy to take in
7,000 without trying. You do need a little bit--about 200 mg a day--to keep fluids
in balance. But all that excess sodium may...
Weaken Your Bones
Too much sodium makes the body excrete calcium, threatening bone density and strength,
says Pao-Hwa Lin, Ph.D., a researcher at Duke University medical center. "The
more you limit sodium, the less calcium you excrete," she says.
Cause Stomach Cancer
A report from Japan found that men with the highest salt intakes had double the
risk of stomach cancer. The subjects ate lots of salted fish and pickled vegetables,
not common in the United States. But Melanie Polk, director of nutrition education
for the American Institute for Cancer Research, says the cancer connection may
show up here as well.
Mess With Your DNA
Researchers from the National Heart, Lung, and Blood Institute found that as they
increase salt levels in laboratory cells, DNA strands begin to break and cell-repair
mechanisms shut down. When salt concentrations return to normal, the cells begin
to repair DNA again. Re-searchers found the same DNA damage in the kidneys of
mice. The next step is to see if these results hold true for human kidneys.
Cause Kidney Stones
In a 5-year study, Italian researchers found that limiting protein and salt may
be more effective in preventing the recurrence of calcium oxalate kidney stones
than the more traditional calcium-restricted diet.
Blame Salt for Your High BP? Sure
We know for certain that sodium raises blood pressure. Roughly 20 percent of American
adults have higher-than-optimal BP. Reducing intake by just 300 mg (about two
slices of Cheddar) drops systolic pressure (the first number) by 2 to 4 points,
and diastolic by 1 to 2 points, a British study shows. Triple that reduction and
you triple the benefit.
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