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Study: Too much salt — and too little — may be bad for you

Study: Too much salt — and too little — may be bad for you

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Finally, a study that says it’s OK to lick every grain of salt from the rim of your margarita.

As long as you don’t go overboard.

A massive, four-year research effort by the Population Health Research Institute, McMaster University and Hamilton Health Sciences, Ontario, Canada, supports the accepted doctrine that too much salt is bad for your health.

But it also indicates that too little may be harmful as well.

The four-year study, of more than 100,000 people in 18 countries, confirmed that consuming more than 5,000 milligrams of sodium a day contributes to high blood pressure, increasing the risk of cardiovascular disease and stroke.

But the blood-pressure effects are less at average levels (3,000 mg to 5,000 mg a day) and aren’t evident at levels of consumption below 3,000 mg, the researchers found.

In crunching the numbers, while the researchers found that low sodium intake was not tied to high blood pressure risk, those who consumed more or less than the recommended range saw increased health risks for cardiovascular conditions.

“In the [Prospective Urban Rural, or] PURE study, we found the lowest risk of death and cardiovascular events in those who consumed moderate amounts of sodium intake (3,000 to 6,000 milligrams per day), with an increased risk above and below that range,” said Martin O’Donnell, an associate clinical professor at McMaster.

The U.S. Department of Agriculture recommends that adults keep their daily sodium intake under 2,300 milligrams, and less than 1,500 mg for those 51 or older, who are African American, or who have hypertension, diabetes or chronic kidney disease.

According to the new research, these recommendations may be too low. The sweet spot for optimal health, the researchers say, may be between 3,000 mg and 6,000 mg per day.

“Low sodium intake does reduce blood pressure modestly, compared to moderate (or average) intake, but low sodium intake also has other effects, including adverse elevations of certain hormones that are associated with an increase in risk of death and cardiovascular diseases. The key question is whether these competing physiologic effects result in net clinical benefit or not,” O’Donnell said in a release.

For their studies, published online Aug. 14 in the New England Journal of Medicine, the scientists took morning urine specimens from more than 100,000 participants on five continents for four years. In addition to their findings on sodium consumption, they noted that the role of potassium consumption in lowering blood pressure and maintaining health often is ignored.

The USDA recommends meeting the potassium recommendation of 4,700 mg per day by eating lots of fruits and vegetables.

Not surprisingly, the research confirmed that consuming too much salt has a tremendous effect on global health: The scientists attributed 1.65 million deaths a year to high sodium intake.

According the study, the average worldwide sodium consumption rate is 3,950 mg per day. The average daily intake in the U.S. is 3,600 mg per day.

In an accompanying editorial in the NEJM, Suzanne Oparil from the University of Birmingham, Alabama, said the findings warrant further research but that the federal government should consider revising current guidelines in light of the new information.

“These provocative findings beg for a randomized, controlled outcome trial to compare reduced sodium intake with usual diet,” Oparil wrote. “In the absence of such a trial, the results argue against reduction of dietary sodium as an isolated public health recommendation.”

Patricia Kime

Patricia Kime is a health writer for Military Times. Reach her at pkime@militarytimes.com.