One More Nail in the Coffin of the Low Salt campaign

Nov• 16•2011

“In my opinion, people should generally not worry about their salt intake,” Dr. Niels Graudal

I have talked a fair amount previously on this site about why I felt salt wasn’t bad for you, see (Is Salt Good for You? Part I, Is Salt Good for You? Part II, Did They Just Say Salt Cures Heart Disease?) .  In the first two articles I noted that, as with water soluble vitamins though even more so the body can easily waste excess sodium in the urine and has strong systems in place to prevent hypernatremia.  I also mentioned that the literature seemed to show people with greater sodium intake living longer and having less disease.  In the third article I mentioned a recent, massive study from Europe that found not only was salt not bad for you but astonishingly in this large study there was an 80% decrease in heart disease amongst those who took in the most salt!  Salt was found to prevent the very disease that we have always been told that salt restriction would prevent. 

I concluded that last article by noting that perhaps the American Heart Association, which continues to champion drastic salt restriction might start looking for a new hobby horse to ride.  In this light I am quite encouraged to see others are buttressing and coming around to my point of view.  An extensive meta-analysis review of the literature on salt was just released by widely read and respected in medical circles Cochrane reviews.   This review published in the American Journal of Hypertension and widely picked up on by the media may be read in full here.

One of the reasons we got in this mess with salt restriction is because of another trend I have railed about on this site, an over reliance on risk factors or surrogate markers for endpoints.  High blood pressure (within reason), is not a disease in and of itself, rather a risk factor for other diseases.  As “debunkers” are so oft to robotically exclaim, “correlation is not causation.”  So is the case here.  While I do believe that high blood pressure is a valid marker for increased risk of heart disease, when ever one has gotten away from looking at the disease itself one runs into the potential for a number of problems.  First off might be, often seen in retrospective studies, the “cart before the horse fallacy” i.e maybe it was the heart disease that caused the high blood pressure not vice versa.  Second maybe a common pathology, say small vessel inflammation has caused both and correcting blood pressure has no effect (again this is not the case as seen in the literature but is presented to illustrate why one is always better off dealing with an actual disease).  Finally and worst of all, the association may be a compensatory response.  For instance someone with severe anemia would be expected to be tachycardic (i.e. have a fast heart beat).  In this case though correcting the tachycardia would not only not be helpful, it would make things much worse.

Alright I think I have beaten that horse to death, I say all this just by means of preface that the Cohrane review restricted itself to only examining a number of laboratory values for levels of various electrolytes and hormones.  They did not formally delve into any clinical endpoints.  My guess, and that is all it is, is that things might have looked worse if they did and that it was a political decision to restrict the scope of the review in this way so as to provide an easy way to save face while changing public health policy.  Even with this restricted scope the findings are almost laughably bad.

First, again not talking about heart disease here, as mentioned in previous write-ups sodium seems protective against that disease, looking at salt’s vaunted effect on blood pressure, yes salt restriction lowers blood pressure.   In people without high blood pressure, after looking at some 167 previous studies, salt restriction caused an average 1% lowering of BP and in those with high blood pressure a whopping 3.5% decrease.  In other words if your blood pressure was 120/80, by restricting salt you could expect to get it down to 119/79.  If your blood pressure was 160/100, it would on average reduce to 154/96.  This is about the most perfect illustration I have ever seen of the distinction between statistical significance and clinical significance.  Yes there is after looking at thousands and thousands of people a clear, statistically significant decrease in blood pressure, it is also so small as to be basically worthless.

The reviewers also note that, as sodium is essential for life, the body has multiple mechanisms in place to attempt to prevent it from being lost in the urine if there is not enough present to easily keep it in its tightly regulated normal physiologic range.  So one point that they bring out that I hadn’t touched on in previous posts is that people who chronically take in too little sodium have elevations in renin, aldosterone, adrenaline, noradrenaline, cholesterol and trigycerides.  While the elevation in cholesterol is the one played up primarily in the press, it can also be noted that a number of these substances would be seen to be involved with 1) attempting to prevent salt loss, (renin and aldosterone) and 2) attempting to preserve blood pressure (adrenaline and noradrenaline).

While it was not the primary theme of their analysis, the reviewers also commented briefly on some clinical endpoints, noting,

“Furthermore, reduced sodium intake seems to harm patients with heart insufficiency and diabetes type 1 and 2. In all three patient groups reduced sodium intake is associated with increased mortality.3,4,5,6

Ho hum,  nothing to see there.   They conclude by stating in part,

“Due to the relatively small effects and due to the antagonistic nature of the effects (decrease in BP, increase in hormones and lipids), these results do not support that sodium reduction may have net beneficial effects in a population of Caucasians.

I would go further and say that interfering with the normal levels of the most prominent extracellular cation, that is to say sodium, looks to be a really reckless way to try and reduce blood pressure.  The evidence tied to clinical end-points at best indicates no effect on heart disease rates, while more likely, restricting sodium is contributing to heart disease and overall mortality in other common diseases.

Of course to get an idea of the conundrum this sort of study poses we can look at an excerpt from a recent news write-up on the article.

“The researchers’ bottom line?

“In my opinion, people should generally not worry about their salt intake,” Graudal told HealthDay.

The findings are published in the Nov. 9 issue of the American Journal of Hypertension.

In July, another review found “no clear benefit” to cutting back salt, saying it did not reduce the likelihood of dying from heart disease or having a heart attack, CBS News reported.

Some experts disputed the new study.

“Over 50 public health organizations can’t be wrong on this one,” Dr. Lawrence Appel, professor of medicine, epidemiology, and international health at Johns Hopkins Medical Institutions in Baltimore, told WebMD.”

Why it’s preposterous I tell you.

So perhaps in about five to ten years time or so after the whole unprofitable and in hindsight nonsensical salt reduction campaign has been swept under the rug it would not surprise me at all to see articles along the lines of “Are You Salt Phobic??? Take the Quiz!“  This would again be to not ever dare mention that medical authorities were morons and dead wrong for decades harming thousands of people along the way, but that once again, an ignorant public is screwing up by being dumb and not following the medical community’s advice.  I would see it reading something like this

“For a long time the medical community debated the merits (and functions) of salt in heart disease.  These complicated and intense discussions often led to some confusing advice for Joe (and Jane) Q Public looking for a simple answer to how much salt should I have in my diet.  The good news, for many years now the majority of authorities have agreed, that with a few exceptions, salt is not so bad for people as once thought and may even have some benefits. 

However, those with a more conspiratorial bent among us, and even some of us who just don’t keep up as much with things as we should aren’t always ready to let it drop so easily.  With urban legends like fluoride being bad for you refusing to die it is understandable that a few people remain “salt phobic” perhaps even thinking, that like the myths on fluoride, the government now doesn’t care about harming them with excess salt in the diet.  Or they simply don’t have the education to get with the times.  So what you need to know is that salt is really not so bad for you.  Get The Facts!  Take the Quiz and learn your Salt IQ.

… Darn, I would have made one heck of a propagandist.  … If someone asks me where the quiz is I will really get frightened ;-)

Ciao,

Paul

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2 Comments

  1. Dan says:

    I’ve always been confused by this one. They teach you in high school biology that the body excretes excess sodium. Of course, this doesn’t establish that the body is able to ideally control blood pressure regardless of salt intake, but surely the initial presumption must have been that restricting salt intake would have no beneficial effect on blood pressure, let alone actually relevant endpoints.

    The question, then, is who is the Ancel Keys of salt restriction?

  2. admin says:

    Well it seems very hard to reasonably dispute at this point that the body strongly compensates for chronic low salt intake, including measures both to preserve salt and blood pressure. And yes, I would agree that as long as one has access to water, there is a tightly regulated upper limit to sodium levels with the kidneys easily wasting excess in the urine

    You got me on how all this got started, maybe I’ll get a chance to look into it sometime, or if you learn anything let us all know.