Study: Excessive Sodium Consumption Has Dire Impact on Global Health

19 Aug 2014 --- Excessive sodium consumption is having a dire impact on global health, killing about 1.65 million people every year, according to a new study released Thursday. The research published in the New England Journal of Medicine adds important evidence to a larger recent discussion about how much sodium people should consume and what kind of impact that has on health, said American Heart Association President Elliott Antman, M.D.

“We have new research indicating that the blood pressure effects of excess sodium can be directly related to cardiovascular disease risk,” said Antman, who is also a professor of medicine and Associate Dean for Clinical/Translational Research at Harvard Medical School and a senior physician in the Cardiovascular Division of the Brigham and Women's Hospital in Boston.

Antman said the new study by Dariush Mozaffarian M.D., Dr.P.H. and colleagues was “a staggering finding.”

"About 1 in 10 cardiovascular deaths were estimated to be attributed to sodium intake of greater than 2,000 milligrams per day,” Antman said. “This is a level exceeded by 99.2 percent of the world’s adults, on average. In the U.S. alone, almost 57,600 annual cardiovascular deaths are attributed to sodium intake at this level.”

The American Heart Association recommends less than 1,500 milligrams per day for ideal heart health, but most Americans consume more than twice that much.

Another study released Thursday, called PURE, questions the link between excessive sodium intake and health risks. However, Antman said PURE contained several substantial methodological issues that limit its usefulness for drawing conclusions about the relationship between sodium intake and health outcomes, and for guiding public health recommendations.

PURE is an observational study that attempts to link dietary sodium intake with subsequent cardiovascular diseases, Antman said. “Interpreting the results of these types of studies was particularly challenging because results can be highly dependent on the types of data collected (and not collected) and the types of analyses performed,” he said.

Antman said these issues include inaccurate measures of sodium intake and inclusion of sick people. The issues are detailed in the American Heart Association’s February 2014 Science Advisory.

“The AHA has been concerned about the quality of these studies and strongly believes that other types of evidence, particularly the well-documented clinical trial relationship of sodium intake and blood pressure, provide the best scientific basis to guide policy,” Antman said.

“The bulk of the available evidence to date shows reduced sodium intake is associated with reduced blood pressure, which itself is associated with a reduction in cardiovascular event,” Antman said. “Along with improving overall diet, controlling weight, and increasing physical activity, lowering sodium intake is key to lowering blood pressure in the general population and improving blood pressure control in those with hypertension.”

The American Heart Association and numerous major national and international public health and scientific organizations have carefully and repeatedly reviewed the evidence and will continue to recommend reducing sodium intake.

The AHA recently launched a new campaign to help consumers lower their sodium intake, and recently more than 30 leading scientists affirmed that the full scope of the evidence continues to anchor the scientific basis for reducing sodium intake.

“Excess dietary sodium intake exacts a tremendous toll on our societies and economies around the world,” Antman said. “Now is a time for action, not hesitation.”

The Grocery Manufacturers Association released the following statement from Dr. Leon Bruner, GMA’s Chief Science Officer, in response to articles recently published in the New England Journal of Medicine on sodium intake and health outcomes.

“GMA members have been reformulating products for decades to provide lower sodium options to help consumers achieve healthy sodium intake levels.  Our industry has reformulated thousands of products to reduce sodium content and meet consumer taste preferences.  The industry has also developed a wide variety of reduced, low or no-added sodium products to help consumers follow recommendations of their health care professionals.  

“And while we are committed to continuing in our efforts to provide consumers with these lower sodium product options, we think that the articles such as those recently published in the New England Journal of Medicine warrant serious consideration by some public health authorities.  In particular, the article by O’Donnell and colleagues further adds to the scientific evidence that low sodium consumption, at levels recommended by public health organizations, may actually increase cardiovascular risk.  Therefore, it is vitally important that we undertake definitive studies to resolve the health impacts, both positive and adverse, of low sodium consumption to ensure public health interventions aimed at lowering sodium consumption provide benefit and do not cause harm.

“In addition, the U.S. Federal government needs to conduct an independent credible reassessment of the Dietary Reference Intakes, which form the basis for current sodium intake recommendations.  This reassessment is critical to establishing public health policy that does not harm the health of US consumers.”