The American Heart Association’s Ongoing A-Salt On Science

I believe the American Heart Association was founded with good intentions.  Really, I do.  But they’ve become a perfect example of the phenomenon described in the excellent book Mistake Were Made (but not by me):  after announcing a public position on an issue, they are incapable of admitting they were wrong.

On their web site, they recommend consuming less than 1,500 mg of sodium per day.  That’s been their position for years.  Since the average American consumes more like 3,500 mg of sodium per day, that means the AHA is telling us to cut our salt intake by more than half to avoid hypertension and, by extension, heart disease.  (We’ll come back to that “by extension” part.)

The AHA certainly isn’t alone in pushing this advice.  The Guy From CSPI has been on an anti-salt jihad for decades, the USDA Dietary Guidelines call for low-salt meals (the USDA compels schools to comply with that advice), and of course Hizzoner Da Mayor in New York City used the coercive power of government to impose his beliefs about the benefits of sodium restriction on food manufacturers.

So how do you suppose the anti-salt hysterics would respond to a big ol’ government-sanctioned study that says they’re wrong?  I’m pretty sure you can guess.  Let’s look at some quotes from a New York Times article titled No Benefit Seen in Sharp Limits on Salt in Diet:

In a report that undercuts years of public health warnings, a prestigious group convened by the government says there is no good reason based on health outcomes for many Americans to drive their sodium consumption down to the very low levels recommended in national dietary guidelines.

Those levels, 1,500 milligrams of sodium a day, or a little more than half a teaspoon of salt, were supposed to prevent heart attacks and strokes in people at risk, including anyone older than 50, blacks and people with high blood pressure, diabetes or chronic kidney disease — groups that make up more than half of the American population.

But the new expert committee, commissioned by the Institute of Medicine at the behest of the Centers for Disease Control and Prevention, said there was no rationale for anyone to aim for sodium levels below 2,300 milligrams a day. The group examined new evidence that had emerged since the last such report was issued, in 2005.

“As you go below the 2,300 mark, there is an absence of data in terms of benefit and there begin to be suggestions in subgroup populations about potential harms,” said Dr. Brian L. Strom, chairman of the committee and a professor of public health at the University of Pennsylvania. He explained that the possible harms included increased rates of heart attacks and an increased risk of death.

Say what?  A low-salt diet may increase the risk of heart attacks and death?  You mean the AHA is recommending we reduce our salt intake to a level that may be dangerous?  Well, take a peek at some of the evidence Dr. Strom’s committee considered (the bold emphasis is mine):

One 2008 study the committee examined, for example, randomly assigned 232 Italian patients with aggressively treated moderate to severe congestive heart failure to consume either 2,760 or 1,840 milligrams of sodium a day, but otherwise to consume the same diet. Those consuming the lower level of sodium had more than three times the number of hospital readmissions — 30 as compared with 9 in the higher-salt group — and more than twice as many deaths — 15 as compared with 6 in the higher-salt group.

Oh, dear.  In a randomized study, the Italians who reduced their sodium intake to levels that are still slightly above what the AHA recommends had more than double the death rate.  Pass the salt shaker, please, and let’s read on:

Another study, published in 2011, followed 28,800 subjects with high blood pressure ages 55 and older for 4.7 years and analyzed their sodium consumption by urinalysis. The researchers reported that the risks of heart attacks, strokes, congestive heart failure and death from heart disease increased significantly for those consuming more than 7,000 milligrams of sodium a day and for those consuming fewer than 3,000 milligrams of sodium a day.

Got that?  The death rate was higher for people who consumed less than 3,000 mg of sodium per day – and the AHA recommends cutting even that level of consumption in half.

So what about the higher death rate among people who consumed more than 7,000 mg per day?  Well, I can think of a couple of possibilities.  Perhaps that much sodium (double the average intake in the U.S.) truly is dangerous.  On the other hand, that’s a LOT of salt to sprinkle on your grass-fed beef, pastured eggs and spinach, so perhaps people who consume that much sodium are the same people who eat a lot of processed food — in all its sugar-and-flour-laden glory.  A super-high sodium intake could just be a proxy for a bad diet in general.

So why might too little salt in the diet be dangerous?  Read on:

There are physiological consequences of consuming little sodium, said Dr. Michael H. Alderman, a dietary sodium expert at Albert Einstein College of Medicine who was not a member of the committee. As sodium levels plunge, triglyceride levels increase, insulin resistance increases, and the activity of the sympathetic nervous system increases. Each of these factors can increase the risk of heart disease.

“Those are all bad things,” Dr. Alderman said. “A health effect can’t be predicted by looking at one physiological consequence. There has to be a net effect.”

Dr. Alderman, if memory serves, once warned that a national effort to force us to consume less sodium would be a giant, uncontrolled experiment that could have unintended negative consequences.  Kudos to him.  We all know what happened with the giant, uncontrolled experiment to remove saturated fats from our diets and replace the calories with grains and vegetable oils.

Anyway, now that a committee created specifically to study the effects of sodium has said there’s no evidence to support pushing low-salt diets on us, let’s see how the people pushing low-salt diets on us are handling the bad news:

Bonnie Liebman, director of nutrition at the Center for Science in the Public Interest, an advocacy group that has taken a strong position against excessive salt consumption, worried that the public would get the wrong message.

“It would be a shame if this report convinced people that salt doesn’t matter,” Ms. Liebman said.

Allow me to interpret Ms. Liebman’s statement:   We’ve been trying to scare people about salt for decades, so it would be a shame if people interpreted a report saying that their current level of salt intake is fine to mean “our current level of salt intake is fine.”

The American Heart Association agrees with her. Dr. Elliott Antman, a spokesman for the association and a professor of medicine at Brigham and Women’s Hospital in Boston, said the association remained concerned about the large amount of sodium in processed foods, which makes it almost impossible for most Americans to cut back. People should aim for 1,500 milligrams of sodium a day, he said.

“The American Heart Association is not changing its position,” Dr. Antman said.

Of course you’re not changing your position, Dr. Antan.  That would require you to admit you’ve been wrong for decades.  I’m guessing you’d rather rip your own ears off than do that.

The association rejects the Institute of Medicine’s conclusions because the studies on which they were based had methodological flaws, he said. The heart association’s advice to consume 1,500 milligrams of sodium a day, he added, is based on epidemiological data and studies that assessed the effects of sodium consumption on blood pressure.

I’ve seen the AHA’s explanation of how the epidemiological evidence supports their position elsewhere.  Here it is in a nutshell:  studies show drastically reducing salt intake can slightly reduce blood pressure, and high blood pressure is associated with heart disease, so that proves reducing salt would reduce heart disease.

If you’re a frequent reader of this blog, you recognize that (ahem, ahem) logic for what it is:  teleoanalysis.  We can’t prove that A causes C, but if we can link A to B and B to C, we can say A causes C.

High blood pressure is indeed associated with heart disease, but that doesn’t prove high blood pressure causes heart disease directly, and it certainly doesn’t prove that restricting salt would prevent heart disease.  As Dr. Richard Johnson has demonstrated in several experiments, hypertension can result from an excess intake of sugar.  It could be that sugar raises blood pressure and also causes heart disease by damaging the endothelial layer in our arteries.

If too much salt causes heart disease and restricting salt therefore reduces heart disease, we should see that relationship directly, not through goofball teleoanalysis.  But we don’t:

The Institute of Medicine committee said it was well aware of flaws in many of the studies of sodium, especially ones that the previous Institute of Medicine committee relied on for its 2005 recommendations. Much of that earlier research, committee members said, looked for correlations between what people ate and their health. But people with different diets can differ in many ways that are hard to account for — for example, the amount of exercise they get. And relying on people’s recall of how much salt they consumed can be unreliable.

The committee said it found more recent studies, published since 2005, that were more careful and rigorous. Much of the new research found adverse effects on the lower end of the sodium scale and none showed a benefit from consuming very little salt.

Although the advice to restrict sodium to 1,500 milligrams a day has been enshrined in dietary guidelines, it never came from research on health outcomes, Dr. Strom said.

Anti-salt hysteria was never based on studies of actual health outcomes.  Neither was anti-fat hysteria.  Yet the American Heart Association pushes both … along with sugary, grain-based cereals that almost certainly do actual damage to our health.

I don’t expect the AHA to ever change its position – on anything – no matter what the evidence.  As I said during a Q&A session after a speech when someone asked me how we can get the AHA, or the USDA, or the ADA to change their positions on diet:  my goal isn’t to change their minds, because I don’t believe that’s possible.  My goal is to make them irrelevant by convincing people to ignore them.

So let’s ignore them.  Pass the salt, please.