McMaster research on “low salt diets” shows how medicine can eat their own

Spoon full of salt 1030Why is it that when medical specialists hear of research findings that are different or contrary to what they use or recommend for common practice, their immediate reaction is a knee-jerk reaction to question the validity of the new findings? Whoa, they say! (H/T NewsWatchCanada).

Of course, sometimes new findings turn out to be incorrect generally or in some instances. However, there are also times when new findings break new ground and save more lives.

I mean, take the simple sterilization technique we know of as “washing our hands.” Everyone knows such washing helps stop the spread of disease. Yet, when Dr. Ignaz Semmelweis, a Hungarian physician suggested such a simple idea back in 1846, to avoid child bed fever, he was condemned to such an extent, he died at age 47 in an insane asylum.

Yet, here we go again. New and contrary meta medical findings that came out yesterday in The Lancet on salt intake by those with heart disease and/or high blood pressure and the immediate reaction is — the study is unreliable.

The study in question combined the data of four other studies and was conducted at McMaster University and Hamilton Health Sciences. They followed 130,000 people in 49 countries and found that, sometimes, when people with cardiovascular disease eat too little salt, it can be as dangerous as eating too much.

This I know personally, having recently spent a night in my local emergency department getting sodium by IV.

Anyway, take a close look at the top of the Lancet page, which was also lambasted for publishing such a piece. There are an awful lot of respectable scientists listed for this pooled research. Then, read the “interpretation of the results.” Nothing is written as blanket statements and the results make sense.

Yet, look at a couple of criticisms from medical experts in an article on the American Heart Association (AHA) website:

(1) “Mark Creager, M.D., president of the American Heart Association and director of the Heart and Vascular Center at Dartmouth-Hitchcock Medical Center at Dartmouth College, questioned the validity of the study….’Today’s widely accepted sodium recommendations are based on well-founded scientific research – and that’s what people should understand.’”

Excuse me? No, the study was not a double blind experimental study. And, yes, the study was a compilation of four other studies. So, what? The McMaster group would also have used well-founded scientific methods in their design and analysis.

(2) “Elliott Antman, M.D., associate dean for clinical/translational research at Harvard Medical School and senior physician in the Cardiovascular Division of Brigham and Women’s Hospital in Boston, said the findings of the new study should be disregarded. ‘This is a flawed study and you shouldn’t use it to inform yourself about how you’re going to eat,’ said Antman.’”

Flawed study? Again, condemnation I expect just because the McMaster study used data from four investigations. And, to justify such a knee-jerk reaction, later on in the AHA article, Antman reflects on how difficult it is to track daily intake of salt. On that, of course, he is no doubt correct. But, that doesn’t mean that individuals can’t have too little sodium in their system.

Antman also talks about the assumptions the McMaster researchers made. Well, as a former academic researcher, I can say, and he has to know, that all researchers make assumptions. That is why, in our reports, we outline our “Assumptions and Limitations” right at the start.

Interestingly, in anticipation of this kind of anti-study criticism, Professor Eoin O’Brien, a molecular pharmacologist at University College Dublin is quoted in the Independent as saying:

When apparent dogma is challenged, we should speak not of controversy but rather accede to the all-encompassing expression of so-called scientific uncertainty, so as to avoid unbecoming rhetoric.”

Exactly!

The crux of the matter is that specialists like Antman, Creager and others should not eat their own by automatically condemning the results of a study they disagree with. Rather, they should find a way to take a closer look and/or attempt to replicate it.