It's Time to End the War on Salt

[Big Don]

It's Time to End the War on Salt
The zealous drive by politicians to limit our salt intake has little basis in science
By Melinda Wenner Moyer | Friday, July 8, 2011 Scientific American EXCERPT
For decades, policy makers have tried and failed to get Americans to eat less salt. In April 2010 the Institute of Medicine urged the U.S. Food and Drug Administration to regulate the amount of salt that food manufacturers put into products; New York City Mayor Michael Bloomberg has already convinced 16 companies to do so voluntarily. But if the U.S. does conquer salt, what will we gain? Bland french fries, for sure. But a healthy nation? Not necessarily.

This week a meta-analysis of seven studies involving a total of 6,250 subjects in the American Journal of Hypertension found no strong evidence that cutting salt intake reduces the risk for heart attacks, strokes or death in people with normal or high blood pressure. In May European researchers publishing in the Journal of the American Medical Association reported that the less sodium that study subjects excreted in their urine—an excellent measure of prior consumption—the greater their risk was of dying from heart disease. These findings call into question the common wisdom that excess salt is bad for you, but the evidence linking salt to heart disease has always been tenuous.
Fears over salt first surfaced more than a century ago. In 1904 French doctors reported that six of their subjects who had high blood pressure—a known risk factor for heart disease—were salt fiends. Worries escalated in the 1970s when Brookhaven National Laboratory's Lewis Dahl claimed that he had "unequivocal" evidence that salt causes hypertension: he induced high blood pressure in rats by feeding them the human equivalent of 500 grams of sodium a day. (Today the average American consumes 3.4 grams of sodium, or 8.5 grams of salt, a day.)
Dahl also discovered population trends that continue to be cited as strong evidence of a link between salt intake and high blood pressure. People living in countries with a high salt consumption—such as Japan—also tend to have high blood pressure and more strokes. But as a paper pointed out several years later in the American Journal of Hypertension, scientists had little luck finding such associations when they compared sodium intakes within populations, which suggested that genetics or other cultural factors might be the culprit. Nevertheless, in 1977 the U.S. Senate’s Select Committee on Nutrition and Human Needs released a report recommending that Americans cut their salt intake by 50 to 85 percent, based largely on Dahl's work.
Scientific tools have become much more precise since then, but the correlation between salt intake and poor health has remained tenuous. Intersalt, a large study published in 1988, compared sodium intake with blood pressure in subjects from 52 international research centers and found no relationship between sodium intake and the prevalence of hypertension. In fact, the population that ate the most salt, about 14 grams a day, had a lower median blood pressure than the population that ate the least, about 7.2 grams a day.
END EXCERPT
Wait two weeks, it will be bad for us again...

 

[Nomad]

Strongly agree! Salt has been seen as the "bad guy" in heart disease for years, with little basis in fact.

It made an appearance previously on a show hosted by Will Riker (ok, Jonathon Frakes) called "Junk Science", which rightly pointed out the tenuous links between dietary salt intake and heart disease, and the fact that both the Mayo Clinic and Harvard Medical School viewed the RDI (recommended daily intake) as ridiculously low (about the same as one dill pickle/day), and more importantly, that it was a made-up number based on nothing. The folks responsible for setting these values literally pulled it out of their collective butts.

It is a fact that NaCl is a vital component of cell function, and that a deficiency of salt can lead to elevated levels of KCl in your body (which in high enough concentrations will stop your heart). No salt diets are dangerous, and should not be undertaken regardless of your physician's advice (ie. get a second, or third, opinion).

This latest study, IMHO, puts the nail in the coffin of the low salt craze... it's too bad that so many physicians and government agencies haven't clued in to this (or have a vested interest in making it happen anyway).

 

[RandomPhantom700]

It is a fact that NaCl is a vital component of cell function, and that a deficiency of salt can lead to elevated levels of KCl in your body (which in high enough concentrations will stop your heart). No salt diets are dangerous, and should not be undertaken regardless of your physician's advice (ie. get a second, or third, opinion).

So wait a minute....going on a low/no-salt diet builds up KCI (whatever the hell that is) which itself causes a heart attack?! Oh the irony...

 

[CanuckMA]

A no-whatever diet is just plain stupid.

And unless you cook from raw material, a low-salt diet is kind of an oxymoron. I do watch my salt intake, and even by selecting only the lower sodium content and it's still frightening how much i consume.

 

[MaxiMe]

conquer salt, what will we gain? Bland french fries, for sure. But a healthy nation? Not necessarily.

Wait two weeks, it will be bad for us again...

If I remember right they did the same type of thin with eggs back in the late 80's or early 90's.

Besides less salt = bad french fries

 

[Sukerkin]

Thanks for bringing this one up, Don :tup:. I've been saying for many years that all the 'crying wolf' about food that goes on does far more harm than just letting people get on with managing their diet as best as their budget allows.

The fretting about how much salt I'm taking in whilst having a Chinese curry does more damage to me than the salt itself.

 

[billc]

I remember interviews with Dana Carvey the actor and comedien from saturday night live. Dennis Miller, when he spoke to Carvey commented that back in the SNL days, Carvey would spend an hour a day on the stair stepper working out like a mad man. Later, when Carvey had to have open heart surgery, he commented to David Letterman that the blockage in his heart was at the exact same location as the blockage in the hearts as two or three other family members. there is so much that medical science has to learn about so many topics that to jump everytime medical or other scientists claim something can be the height of silliness. Do things in moderation and that is probably your best bet to stay alive, and hope that the bioloigical lottery doesn't have a nasty surprise for you. That is all you can really do.

 

[cdunn]

So wait a minute....going on a low/no-salt diet builds up KCI (whatever the hell that is) which itself causes a heart attack?! Oh the irony...

The important factors here are the balance of sodium chloride and potassium chloride, and the overall level of osmosis affecting ions. In the nervous system, the balance of the two ions creates the potential across a nerve cell interface that allows transmission. In a very, very crude analogy, you can think of the sodium in table salt as the hand that pushes open a door, and potassium as the spring that pulls it shut automatically. If either fails, the door doesn't work as intended, and you're in deeeeeep trouble. This is the same basic mechanism that passes all nervous signals, including those to the cardiac muscle fiber, which has some relatively more stringent requirements than skeletal or smooth muscles, and therefore tends to go off first. Sodium also controls the water content of your cells, by driving osmosis.

So, if you get too far out of balance in either direction, you're pretty screwed. BUT, your body manages a pretty complex buffering system in the blood, in order to maintain that balance. Your kidneys can do a reasonable job of altering output in the urine to dump out too much or hold on to too little.

We know pretty well what the minimum is, and pretty well what the LD50 is. We know pretty well what the relationship between extremely excessive salt consumption and high blood pressure is. What we don't really have a clear picture of is the relationship between hypertension and heart failure; it will change between people. We thought we knew, but we have conflicting evidence now. We have indicators for some kinds of heart issues, but not others. And what we don't know at all is what the true optimum for consumption is. This will also vary from person to person - and from genetically related population to genetically related population. (Race has only a tenuous relationship to these.)

On the other hand, we are also faced with a corporatized food system that adds salt for a myriad of reasons completely unrelated to our health. Salt appeals to our sense of taste, evolved for a time before we learned to pull 210 million tons of salt a year out of the planet. It hides a lot of shortcomings in recipies. It's a potent preservative. There's lots of reasons for it, but not all of them good for us.

Are we consuming in excess of what we need? Almost certainly. Are we consuming enough to do us direct harm? Good question - For me, at 150 lb, with a known cardiac arrythmia, gout, and a family history of heart failures and hypokalemia, it's probably better safe than sorry, and accordingly, I generally choose lower sodium when available. For anyone else? Well, that's your call.