22 May Controversy Over Salt Content Continues

MedicalResearch.com Interview with:
Prof Andrew Mente PhD
Clinical Epidemiology and Biostatistics, McMaster University
Hamilton, Canada

MedicalResearch.com Editor’s Note:  Dr. Mente discusses his Lancet publication regarding salt intake below.  Dr. Mente’s findings are disputed by the American Heart Association (AHA).  A statement from the AHA follows Dr. Mente’s comments.

MedicalResearch.com: What is the background for this study? What are the main findings?

Prof. Mente: Several prospective cohort studies have recently reported that both too little and too much sodium intake is associated with cardiovascular disease or mortality. Whether these associations vary between those individuals with and without high blood pressure (hypertension) is unknown.

We found that low sodium intake (below 3 g/day), compared to average intake (3 to 6 g/day), is associated with more cardiovascular events and mortality, both in those with high blood pressure and in those without high blood pressure. So following the guidelines would put you at increased risk, compared to consuming an sodium at the population average level, regardless of whether you have high blood pressure or normal blood pressure.

High sodium intake (above 6 g/day) compared to average intake, was associated with harm, but only in people with high blood pressure (no association in people without high blood pressure).

MedicalResearch.com: What should readers take away from your report?

Prof. Mente: The findings suggest that lowering sodium intake is best targeted at populations with high blood pressure who also consume high sodium diets (which represents only about 10% of the overall population).

MedicalResearch.com: Is there anything else you would like to add?

Prof. Mente: The current recommendation for low sodium intake is based on an assumed cardiovascular benefit, inferred from small blood pressure trials. Current evidence, from international studies conducted over the past 6 years, suggest that those assumptions may be flawed, and guidelines need to be updated to reflect contemporary evidence.

Citation:

Associations of urinary sodium excretion with cardiovascular events in individuals with and without hypertension: a pooled analysis of data from four studies
Mente, Andrew et al.
The Lancet , Volume 0 , Issue 0 ,
DOI: http://dx.doi.org/10.1016/S0140-6736(16)30467-6
Published online: 20 May 2016

American Heart Association strongly refutes study findings on sodium consumption: 
American Heart Association Comment
DALLAS, May 20, 2016 -The American Heart Association strongly refutes the findings of a May 20, 2016 article in The Lancet by Mente, et al, that suggest low sodium intake is related to a higher risk of heart disease and death. On the contrary, the link between excessive sodium and high blood pressure – as well as higher risks of heart disease, stroke, heart failure and kidney disease – is indisputable. Lowering sodium is more important than ever. Consider the following:

• One-third of Americans have high blood pressure
• 90% of all American adults will develop hypertension over their lifetime
• Heart disease and stroke are the world’s two leading causes of death
“This is a flawed study and you shouldn’t use it to inform yourself about how you’re going to eat,” said Mark A. Creager, M.D., president of the American Heart Association and director of the Heart and Vascular Center at Dartmouth-Hitchcock Medical Center. “The large body of science clearly shows how excessive amounts of sodium in the American diet can cause high blood pressure, which can lead to disease and even death.”

“The public should not be confused by the flawed study reported in The Lancet. The American Heart Association and many other reputable organizations urge the vast majority of persons around the globe to consume less sodium. This study offers no credible evidence that lower sodium intake can be harmful. And many other well-done studies support the recommendation of the association to limit daily sodium intake to 1500mg per day,” said Daniel W. Jones, MD. past president, American Heart Association; Sanderson Chair in Obesity, Metabolic Diseases and Nutrition; Director, Clinical Population Science, Mississippi Center for Obesity Research.

Evidence shows there are specific people who should not lower sodium intake including those regularly working in extreme heat, or those with specific, but uncommon, illnesses. But suggesting most Americans don’t need to reduce sodium consumption is off the mark. “Decades of experimental work in the laboratory, where other factors known to affect the cardiovascular system can be closely controlled, have demonstrated the importance of dietary sodium in worsening hypertension. Importantly, that evidence also shows that the impact of dietary sodium can differ greatly from one individual to another,” said Gregory Fink, PhD, past Chair on American Heart Association’s Council on Hypertension.

“Low sodium excretion, based on spot urine collections, is a misleading measure of usual dietary intake over a lifetime,” Dr. Creager added. “Other factors, beyond dietary sodium intake, are present and probably are responsible for the association of lower sodium excretion with cardiovascular disease – factors such as reduced calorie intake, low physical activity, or a concurrent illness.”

The suggestion from The Lancet article that most people are eating the right amount of salt runs counter to established recommendations as well as the recent movement toward limiting sodium in packaged goods and restaurant meals. The AHA is one of numerous health organizations and governmental bodies that encourage sodium limits for health reasons. The U.S. government recommends no more than 2,300 milligrams a day, and the World Health Organization recommends 2,000. Unfortunately, most Americans consume more than twice the American Heart Association’s recommended limit of 1,500 milligrams per day.

The association’s guidelines are based on the expert review of an expansive body of the best-available scientific research over time. While The Lancet article folds into the landscape of available evidence, we must be discerning in the evidence that defines public policy recommendations.

The association is committed to helping Americans achieve better cardiovascular health. Encouraging lower sodium intake is an important part of that commitment, and will ultimately help save lives.

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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Last Updated on May 22, 2016 by Marie Benz MD FAAD