The Nutrition Debate #248: Salt Warnings: Confusing and Contradictory

Here we go again! Another study about salt. It seems that Australians “pay little attention to salt warnings,” according to an eponymous story from Medscapemedicalnews.com. The study (involving just 143 people) doesn’t support the headline, but what made this story interesting to me were the stories that ran with and mostly against it. The Reuters Health story, about a research study at the University of South Australia, appeared online August 13^th in Appetite.

The recommended upper limit for salt intake for Australians is 6g/day. Six grams of salt a day seems like a lot, but it’s essentially the same as the U. S. Dietary Guidelines (2010) recommendation for “healthy people,” which is 2,300 mg/day of sodium, or about 1 teaspoon of sodium (over 2.5 tps of salt). Six grams of salt x 0.393 (the % sodium in NaCL) = 2,358 mg of sodium. For adults with high blood pressure, the recommendation is no more that 1,500 mg/day of sodium. According to Medscape, in Australia today men eat more sodium (2,907 mg/day) than women (1,962 mg/day).

The next day the prestigious New England Journal of Medicine (NEJM) published 3 major papers on the health effects of sodium consumption in 101,945 individuals in 17 countries, all questioning the science of salt restriction. And back in 2013, the Institute of Medicine (IOM) reviewed the evidence for the suggested guideline for sodium intake and reported that there was no evidence to support the 1.5 g/d limit. I reported on this “The Nutrition Debate #153”here.

How does one decipher this conundrum? Well, Eric J Topol, MD, the Editor-in-Chief of Medscape Medical News, thought it was time to bring some clarity to the issue in this August 26^th post addressed “Dear Medscape Readers.” You really oughta read this piece. “This is important stuff that the public wants to know about,” Dr. Topol says. Even more compelling is this chart that Dr. Topol describes as “the most striking evidence of the relationship of sodium and cardiovascular events…”

Dr. Topol’s analysis of the chart: “Although there was a trend of higher adverse cardiovascular events with sodium excretion greater than 5 g/day, this was much more pronounced at levels less than 2 g/day. In other words, consumption of too little sodium is as harmful as consumption of too much sodium. In fact, the AHA guidelines would lead – according to this latest research – to about a twofold risk for major adverse events.”

Dr. Topol then cites “the real coup de grace: the Wall Street Journal’s editorial column, ‘The Salt Libel’ (subscription required, unfortunately), which highlighted this conclusion: ‘[T]he illusion that science can provide some objective answer that applies to everyone…is a special danger.” He then quips, “I believe that adequately sums up all there is to say about sodium, at least for now.” But he notes, “The AHA… isn’t backing off from its 1.5 g/d sodium guideline.”

What followed in Dr. Topol’s rather rare editorial to his large, mostly doctor audience was the piece de resistance:

“But I think there’s a big lesson here about guidelines without adequate evidence. They can do harm. Hopefully this lesson will prove to be impactful, because that certainly has not been the case to date (as in cholesterol/LDL, BP, PSA, mammography and a very long list of poorly conceived non-anchored guidelines. Isn’t it about time to recognize that there shouldn’t be rules for populations? Some people are exquisitely sensitive to salt intake, while others are remarkably resistant. Average is over” (emphasis added by me).

Well, the “average” Australian male’s sodium intake, if they are ignoring salt warnings at 2,907 mg/day (sodium), is in my view still on the low side. And the Australian woman, who it appears to me is trying hard to comply with sodium guidelines, and whose intake is 1,962 mg/day, does so at their own great peril! The optimum intake of sodium, from my reading of the chart, is between 4 and 5 grams a day. That is 10.2 and 12.7 grams of salt (3½ to 4 tablespoons of salt).

The second thing that caught my attention in this Medscape piece is that Lauren Graf, a New York dietician who was not involved in the study, but who was interviewed for Medscape about the piece in Appetite, turned the whole discussion away from sodium intake and “hidden sodium in processed food.” She called the study “interesting and consistent with other research,” but moved quickly to say, “…but hidden sodium is only one of many unhealthy aspects of processed foods that have the potential to affect heart health directly and indirectly.” She works for the Montefiore-Einstein Cardiac Wellness Program in New York. That’s pretty good advice coming from a cardiac wellness program.

“If a diabetic were to choose a low-sodium version of a highly-processed cereal or bread, they’re going to have a false sense of security in terms of doing something good for their health because they should be limiting a lot of those foods for a lot of reasons,” she said. “The focus,” she continued, “should be on shifting to eating real food and less processed food, which will automatically reduce the sodium content and increase the intake of beneficial antioxidents and fiber.”

Really good advice! It sounds like the message about eating more real food and less processed food is starting to get out there. Huzzah! Huzzah!

(Salt intake, btw, is measured by how much sodium you excrete in your urine. I guess sweat doesn’t count, or can’t be easily collected.)