WEDNESDAY, Oct. 20 (HealthDay News) -- Americans still consume
more salt than they should, despite decades of warnings linking
high-salt diets with an increase in blood pressure and a higher
risk of heart disease and stroke.
A new Harvard study finds salt intake is about the same today as
it was nearly 50 years ago, an amount well above recommended
guidelines, noted Dr. Adam M. Bernstein, the study's lead
Bernstein, a research fellow in the Harvard School of Public
Health's department of nutrition, and colleague Dr. Walter C.
Willett analyzed 38 studies, published between 1957 and 2003, that
reported the amount of salt that the more than 26,000 participants
passed in their urine. This test is the most reliable estimate of
The researchers thought they would find that salt intake had
increased over time because Americans eat more processed foods
today than in 1957. But decade after decade, people consistently
consumed about 3,700 milligrams of sodium a day, the data showed.
Current sodium guidelines advise up to 2,300 milligrams (about one
teaspoon) a day for adults, and 1,500 milligrams for those who have
or are at risk for high blood pressure.
The study appears in the November issue of the
American Journal of Clinical Nutrition.
Since the 1980s, the U.S. government has recommended cutting
back on salt in order to reduce blood pressure and cardiovascular
disease risk. But the ongoing U.S. National Health and Nutrition
Examination Survey (NHANES), which provides a snapshot of
Americans' health and nutrition status every two years, regularly
suggests that Americans consume more salt now than they did 20 or
30 years ago, Bernstein said. However, those data are based in part
on survey participants recalling what they ate, rather than on the
more accurate urine samples.
The study also noted that although Americans' salt intake has
remained relatively constant for almost 50 years, their rates of
high blood pressure and heart disease have increased in the past 20
years. But America's ever-rising obesity rates may play a more
critical role in this rise than salt intake, the researchers
The study's main message "is that for all the intense effort to
get Americans to limit their salt intake, the evidence suggests
that this hasn't happened," said Dr. David McCarron, lead author of
an accompanying journal editorial.
The average salt intake of the Americans in the Harvard study is
similar to that found in international studies, the editorial said.
This similarity suggests that humans may need a set amount of salt
and are hard-wired to seek it, said McCarron, an adjunct professor
with the department of nutrition at University of
McCarron led a 2009 study that analyzed urine samples in 19,151
people in 33 countries over a 24-year period. The average daily
sodium intake was 3,726 milligrams a day, even across diverse
populations and diets, and with no evidence of change over time. In
a 12-year study of more than 13,000 people from Switzerland, also
published in 2009, people averaged around 3,680 milligrams a day.
"It's spooky how consistent this number is," said McCarron.
In light of these studies, the editorial said, the government
should limit its sodium guidelines to those at risk for high blood
pressure and heart disease rather than issue broad,
one-size-fits-all guidelines for everyone. McCarron has consulted
with the Salt Institute and the food industry in the past.
Fully 69 percent of American adults meet these risk guidelines,
a 2009 study by the U.S. Centers for Disease Control and Prevention
found. These high-risk folks include people over 40, blacks, and
those with slightly elevated blood pressure (pre-hypertension).
And there's a call to do more to get Americans to ease up on
salt. In April, a report by the Institute of Medicine called for
the U.S. Food and Drug Administration to set national standards for
salt added to processed foods. According to that report, 32 percent
of U.S. adults have high blood pressure. And the American Medical
Association estimates that cutting the amount of salt in processed
foods by half could save 150,000 lives in the United States each
Bernstein said he supports the government's sodium guidelines
and disagrees with the "set point" theory. "A set point would not
explain why other populations have substantially different sodium
intakes," he said.
There's more on lowering daily salt intake at the
U.S. Food and Drug Administration.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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