Guest Essay by Kip Hansen
Prologue: This is the first in a series of several essays that will discuss ongoing scientific controversies, a specific type of which are often referred to in the science press and elsewhere as “Wars” – for instance, this essay covers the Salt Wars1. The purpose of the series to illuminate the similarities and differences involved in each.
Warning: This is not a short essay. Dig in when you have time to read a longer piece.
From the New York Times, Wednesday, June 1 2016, “F.D.A. Proposes Guidelines for Salt Added to Food”:
“The Food and Drug Administration proposed voluntary guidelines for the food industry to reduce salt on Wednesday [1 June 2016], a move long sought by consumer and public health advocates who said the standards could eventually help save thousands of American lives.”
….
“Americans eat almost 50 percent more sodium than what most experts recommend. High-sodium diets have been linked to high blood pressure, which is a major risk factor for heart disease and stroke.”
….
“While there has been some scientific controversy over how much to reduce sodium, scientists at the F.D.A. said the health advantages are beyond dispute.”
If one follows the offered link to “some scientific controversy” one finds this report in the New York Times piece No Benefit Seen in Sharp Limits on Salt in Diet, by Gina Kolata, May 2013, regarding the Institute Of Medicine of the National Academies booklet-sized review of the entirety of modern science on salt intake and health titled “SODIUM INTAKE IN POPULATIONS: ASSESSMENT OF EVIDENCE” written by its Committee on the Consequences of Sodium Reduction in Populations issued in 2013 [free pdf].
Among the several findings and conclusions of this massive review is:
“Finding 2: The committee found that the evidence from studies on direct health outcomes was insufficient and inconsistent regarding an association between sodium intake below 2,300 mg per day and benefit or risk of CVD outcomes (including stroke and CVD mortality) or all-cause mortality in the general U.S. population.”
And further:
“…the committee found that the available evidence on associations between sodium intake and direct health outcomes is consistent with population-based efforts to lower excessive dietary sodium intakes, but it is not consistent with recommendations that encourage lowering of dietary sodium in the general population to 1,500 mg per day.”
Gina Kolata, the long-time NY Times Health journalist, summarized is this way:
“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.”
The American Journal of Hypertension, October 2013 issue, covered the topic extensively in this issue largely dedicated to the Salt Wars following on the Institute of Medicine’s 2013 report (mentioned and linked above). The INTRODUCTION: The Salt Discourse in 2013, written by Theodore A. Kotchen, characterizes the findings of the IOM report as:
The IOM report concluded the following:
- “The evidence supports a positive relationship between higher levels of sodium intake and risk for CVD.”
- “The evidence on health outcomes is not consistent with efforts that encourage lowering of dietary sodium in the general population to 1,500 mg/day.”
- “There is no evidence on health outcomes to support treating population subgroups differently than the general US population.”
Yet, as we see reported on the first of June 2016, The Food and Drug Administration just issued guidelines to the processed food industry based on the assumption that “the health advantages [of population-wide dietary salt reduction] are beyond dispute”.
Are the health advantages of population-wide dietary salt reduction beyond dispute?
Hardly. The latest salvo fired in what has long been called The Salt Wars1 was published last month, on 20 May 2016. A huge international review study [paywalled] led by Professor Andrew Mente, PhD, the title of which begins with “Associations of urinary sodium excretion with cardiovascular events….”, in one of the world’s leading medical journals, The Lancet. The study had a cohort of 133,000 individuals across 49 countries and was undertaken and written by 29 internationally recognized researchers, all PhDs and/or MDs. Their published interpretation of its findings is:
“Interpretation: Compared with moderate sodium intake, high sodium intake is associated with an increased risk of cardiovascular events and death in hypertensive populations (no association in normotensive population), while the association of low sodium intake with increased risk of cardiovascular events and death is observed in those with or without hypertension. These data suggest that lowering sodium intake is best targeted at populations with hypertension who consume high sodium diets.” [emphasis mine – kh]
In an accompanying Comment [also paywalled] in the same issue of The Lancet, Professor Dr. Eoin O’Brien of the Professor of Molecular Pharmacology, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, and past President of the Irish Heart Foundation writes:
“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. The issue of population strategies for salt consumption is a good case in point. There is no argument other than “excessive salt in the diet raises blood pressure”, and that strategies to reduce salt in individuals with hypertension prevent the cardiovascular consequences of the disease. However, the corollary that reducing sodium intake across populations will be beneficial to all, has been challenged with the assertion that doing so might indeed be harmful.”
Todd Neale reports bluntly on the study for tctmd.com (an industry supported news aggregator covering interventional cardiology news and education):
” Consuming less than 3 grams of sodium per day is associated with a greater risk of all-cause death or major cardiovascular events compared with more moderate intake in both hypertensive and normotensive individuals, an observational study of more than 130,000 participants has shown. In contrast, consuming 7 grams or more per day is tied to worse outcomes in hypertensive patients only.
The findings conflict with advice by the American Heart Association (AHA) to consume no more than 1.5 grams of sodium per day.”
The Neale article continues with:
But Daniel Jones, MD [past President of the American Heart Association] (University of Mississippi Medical Center, Jackson, MS), speaking to TCTMD on behalf of the AHA, which issued a public statement refuting the study, strongly disputed its results.
“This is a flawed study, and no health policy should be based on this study,” he said. It’s “difficult to do good studies, but the preponderance of the evidence is that most people eat too much sodium and that people’s general health will be improved by eating less sodium. This message that people should be concerned about eating too little sodium is just something that should not be taken seriously.”
Indeed, the American Heart Association fired back with a press release and web page titled “Experts criticize new study about salt consumption”. Two experts, the current and immediately-past President of the AHA, are quoted:
Mark Creager, M.D., president of the American Heart Association…..“The link is proven between excess sodium and high blood pressure, and I find it worrisome that adoption of the authors’ recommendations may reverse the progress that has occurred in modifying dietary sodium intake and reducing the risk of high blood pressure and its effect on heart disease and stroke,” Creager said. “Today’s widely accepted sodium recommendations are based on well-founded scientific research – and that’s what people should understand.”
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, immediate past president of the AHA. “The AHA has reviewed the totality of the evidence and we continue to maintain that no more than 1,500 milligrams of sodium a day is best for ideal heart health.”
So far, that’s three American Heart Association Presidents trotted out to attack the new study and its findings, which agree with and expand on the findings of the National Academies’ Institute of Medicine from 2013.
What in the world is going on here?
* * * * *
Let’s roll the clock back 15 years, to the turn of the century and look at this article from the New York Times Science section: With Dietary Salt, What ‘Everyone Knows’ Is in Dispute by Abigail Zuger (NY Times, January 9, 2001). Zuger leads with this:
“Diet fads may come and go, but low salt is forever. Or so, at least, any reasonable person might conclude from the consistent message in most guidelines over the last two decades: eat less salt.
But behind the official pronouncements rages one of the longest, most vituperative battles in medicine. It has continued despite a decades-long procession of ”landmark” studies, each designed to end the debate, and each only provoking more disagreement.”
Already, in 2001, the Salt Wars have been raging for decades. Zuger outlines the battle lines for us:
“One set of scientists, backed by most of the country’s major health organizations, maintains that cutting back on salt is good for people, whether they have high blood pressure or not.
”Salt matters,” said Dr. Frank Sacks, an associate professor of nutrition and medicine at Harvard, who led the most recent study. ”The results are so clear-cut, there’s just not much controversy left.”
Dr. Jeremiah Stamler, an emeritus professor of preventive medicine at Northwestern University Medical School in Chicago, who has spearheaded the anti-salt forces for decades, said that he himself stopped eating most salt in 1948.
”The question of salt is settled,” Dr. Stamler said. ”It’s a food additive we don’t need.”
And on the proverbial other hand:
“But other equally respected scientists still rally firmly behind the salted pretzel, maintaining that there are better tools for controlling blood pressure than salt reduction, and that low-salt eating may actually be harmful to health. [emphasis mine – kh]
”The problem is not so much whether we have too much salt in our diet as it is the deterioration of the American diet,” said Dr. David McCarron, a professor of medicine at Oregon Health Sciences University in Portland, who argues that salt makes little difference in blood pressure control when people eat balanced diets that emphasize fruits, vegetables and low-fat dairy products. ”That’s really the issue.”
Dr. Michael Alderman, a professor of medicine and epidemiology at Albert Einstein College of Medicine in the Bronx and past president of the American Society of Hypertension, said: ”I don’t believe there is any basis whatsoever for a public health recommendation for eating any particular sodium content diet. A scientific problem ought to be solved by data. And there is no data.”
Fifteen years ago, the then-recent dual studies undertaken by the National Institutes of Health – called “Dietary Approaches to Stop Hypertension” or the DASH studies – had shown that blood pressure could be better controlled by eating a well-rounded diet high in fruits, vegetables, and dairy. This so-called DASH diet produced blood pressure reductions on the same level as blood pressure medications. The second DASH study seemed to show that the DASH diet coupled with salt reduction produced even better results. Both studies have been challenged by both sides of the Salt Wars, both sides interpreting the results in favor of their viewpoints.
“….Dr. Stamler of Northwestern said….[regarding] the findings of the second DASH study, ”there is no question that for everyone else [those who do not already have optimal blood pressure] there is a significant effect from lowering salt.”
however
“Not so, Dr. McCarron said. ”The most important finding in the second DASH study is the unequivocal evidence that the first step in blood pressure control should be adding things missing from the diet: the fruits, vegetables and low-fat dairy products,” he said. ”If people have to put their money down on a dietary intervention, the blood pressure response they will get from that is far better than from worrying about salt.”
[all quotes immediately above are from the Zuger NY Times piece – kh]
On a pragmatic level, the DASH studies found that “cutting back on sodium from 3,300 milligrams a day to 2,400 milligrams [note: this recommendation has since been dropped even further to 1,500 mgs/day – kh] lowered blood pressure in the study by an average of 2.1/1.1 for people who ate a normal diet. Changing to a DASH diet lowered their pressure substantially more, by 5.9/2.8, without any salt restriction at all.” [included quote from the Zuger NY Times piece – kh]
Let’s look at that more closely. A salt reduction diet, cutting back to 2,400 mg/day, for people with a normal diet, resulted in an average lowering of blood pressure (BP) of 2.1/1.1 (mmHg). If your blood pressure (BP) was 150/95 (which was and is considered high), then, on average, salt reduction to 2,400 mm/day would lower your BP to 147.9/93.9. That amount of improvement does not stand up as a Minimal Clinically Important Difference – “The MCID defines the smallest amount an outcome must change to be meaningful to patients.” In other words, no one’s high BP is cured by a reduction of 2.1/1.1, such a small reduction doesn’t improve a patient’s well-being or general state of health. In fact, that is a fraction of the “white coat effect” which raises some people’s BP by 10 to 30 mmHg simply because their BP is being measured by a doctor – “The term white coat hypertension may be used if you have high blood pressure readings (i.e. readings that are consistently 140/90mmHg or above) only when you are in a medical setting. Your blood pressure readings may be normal when they are taken at home.”
This brings us full circle back to the most recent Salt Wars salvo, the Mente et al. study in the latest issue of The Lancet, “Associations of urinary sodium excretion with cardiovascular events….” [paywalled], which, 18 years later, confirms the findings of Alderman: “Compared with moderate sodium intake, high sodium intake is associated with an increased risk of cardiovascular [CV] events and death in hypertensive populations (no association in normotensive population), while the association of low sodium intake with increased risk of cardiovascular events and death is observed in those with or without hypertension.” In other words, while high sodium (salt) intake does increase the risk of CV or death in those who are already hypertensive (have high BP), enforced low sodium diets, population wide, will have overall negative health effects – increasing risk of CV events and increasing risk of all-cause death – for everyone, without respect to BP – the most optimum health outcomes are found with moderate salt intake regardless of BP status.
For the American Heart Association, and its allies who share its long-term anti-salt stance, these findings — no matter how scientifically sound, no matter how robust, no matter that they replicate and confirm earlier findings – are simply unacceptable. The AHA has publicly stated that these findings should be “disregarded”.
Let’s take a break for a minute. The information discussed so far represents a only a tiny bit of the vast literature involved in the Salt Wars. I have purposefully steered clear of science journalist Gary Taubes and his work in the NY Times and in Science magazine, which together comprise the best summary of the Salt Wars up to mid-1998. Taubes had written about the Salt Wars for more than two decades. [He is perhaps more well-known for his efforts in the Obesity Wars.] His work – on the pragmatic salt-is-salt side of the Wars – is legendary. I have also avoided the opinions of and work by “The Salt Guru”, Morton Satin, who came out of retirement to be the Vice President of Science and Research at The Salt Institute, a non-profit trade association based in Alexandria, Virginia, an association that taints his work in the eyes of many. (Before that, Satin spent sixteen years as the Director of the United Nations Food and Agriculture Organization’s Agribusiness Program.) Satin’s general view is that the salt debate is filled with shoddy science and outright misinformation.
In a funny aside – and many reading here will recognize this situation — it has been reported that Satin has claimed Taubes won’t even take his phone calls for fear of becoming tainted by contact. Taubes denies this. But, I mention it because, as in other modern scientific controversies, “guilt-by-association” is rampant – a modus operandi practiced by all factions.
What We Know About Dietary Salt:
- Salt is an absolutely necessary element of the human diet – humans die without adequate salt intake.
- For most people, consuming a moderate amount of salt daily (2,500-5000 mgs) has no adverse effects.
- High blood pressure (BP) is associated with cardiovascular disease and risk of premature death.
- For almost everyone, eating more salt causes an increase in BP, but the increase is not clinically important, averaging around 2.1/1.1 mmHg.
- For a certain percentage of people, believed to be in the 10-15% range, who can be labeled “salt sensitive”, dietary salt causes higher BP and for those already suffering high BP and who have a high salt intake, dietary salt reduction combined with improved diet (the DASH diet – more fruits, vegetables, and low-fat dairy, specifically) can help reduce BP to healthier levels.
- For most people, a diet too low in salt increases risk of cardiovascular events and increase risk of all-cause death.
- The science to quantify what constitutes “too low”, “moderate”, and “too high” regarding salt intake is best characterized as “somewhat uncertain”.
What We Know About Salt Politics:
- The Salt Wars have been raging for 30 years, at least.
- One side of the Salt Wars believes that because dietary salt increases BP (in most people just by a small amount) and causes a big increase BP in some people, coupled to the idea that high BP is associated with increased heart disease and risk of death, that governments should take action to reduce the salt intake of everyone – population wide – through regulation of the food industry, setting dietary guidelines, etc. Arrayed on this side we find the American Heart Association, United Nations’ World Health Organization, and the US FDA. Many food and diet advocacy groups stand with the AHA against salt. Taken together, these groups represent a view that consists of a “bureaucratically entrenched hypothesis advocating an enforced solution”.
- The opposition believes that the science is not adequate to mandate a population-wide reduction of salt intake, maintaining that, in addition to being not necessary, it will cause harm instead of good, increasing cardiovascular events and premature death among all groups. The majority of scientists on this side of the issue also hold that the DASH diet is far more effective in reducing high BP than salt reduction.
- Despite the mounting evidence of harm from population-wide enforced salt reduction, various government agencies have been passing rules, regulations, and guidelines to force the food processing industry and, most recently, in New York City, mandatory labeling of highly salted foods by chain restaurants.
- As in all modern scientific controversies, the faction occupying a societal Bully Pulpit, in this case the AHA, FDA, and WHO, has a huge advantage, even when the hard scientific facts are not on their side. [“A bully pulpit is a sufficiently conspicuous position that provides an opportunity to speak out and be listened to…. a terrific platform from which to advocate an agenda.”]
- The Salt Wars are an exemplar of what can happen when a hypothesis is scientifically correct but its real-world overall effect becomes grossly exaggerated. This can lead to a “mandated solution” which is then sold as a cure-all for some existing problem. As the underlying science is in fact uncertain, scientists in support of this view must turn themselves into advocates to make their case. Political advocates in turn pretend to be scientists, advising governments to enforce a “one-size-fits-all” solution on the whole society – even though it is probable that the claims of benefit range from uncertain, at best, to nonsensical [see footnote 2 for the my rationalization for this statement in the Salt Wars].
Modern scientific controversies, sub-category Science Wars, all follow a similar pattern and have common features. As this series progresses, it will become obvious what these features are and the harm they cause to the reputation of Science and Scientists.
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Footnotes:
- Please note that in all instances, the word salt in this essay, and in all included quotes, refers to common table salt, sodium chloride, in all of its customary forms found in kitchens, restaurants, grocery stores and food processing plants. The use of the term “Salt Wars” does not originate with me but has been in common usage in science journalism for some time. I offer this link: Scientific American – Health – The Salt Wars Rage On: A Chat with Nutrition Professor Marion Nestle in support of its use. (Nestle is pronounced like the action “to nestle”, Dr. Nestle is not related to the famous chocolate fortune family). The term’s use in this essay (and SA) is not to be confused with the many actual armed conflicts over the ages and around the world that have shared the title Salt War.
- From the same source as Footnote 1, I quote Marion Nestle “I was once at a sodium meeting at which there were a bunch of statisticians. And I left with the statisticians and they said that “anyone who thinks that salt has anything to do with hypertension is delusional.” And that was on the basis on the clinical trials that show so little. And yet every single committee that has dealt with this question says, ‘We really need to lower the sodium in the food supply.’ Now either every single committee that has ever dealt with this issue is delusional, which I find hard to believe—I mean they can’t all be making this up—[or] there must be a clinical or rational basis for the unanimity of these decisions.” And “Everybody argues about every clinical trial no matter what the conclusion. So I find the whole thing completely fascinating.”
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Author’s Comment Policy:
I have been sidelined for the last six-months by a heart attack that acted to reset my priorities somewhat. I have, thankfully, fully recovered and spent a month sailing with family up the Eastern Seaboard of the United States, with my youngest son acting as Captain.
As always, I will be glad to answer your questions about the Salt Wars – which I have followed since the 1980s. I am open to suggestions on which of the current Science Wars to cover in this series, I am aware of a half dozen or more.
I realize that many readers here will want to move on immediately to discuss the Climate Wars – one of the distinctive science wars of our day. I ask that you please try to restrain yourselves – we’ll get to that later on in the series.
The last essay in the series will be an attempt to layout a coherent pattern of modern science wars and maybe suggest ways that the different science fields themselves can break these patterns and return their specific area of science back to the standards and practices that should exist in all scientific endeavors.
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Thank you for writing this. It was most appreciated and I enjoyed every word. This looks like it will be an interesting and thought provoking series. I look forward to the next installment.
We are our genes. What is good for the goose may not be good for the gander. Individual differences really determine a great deal regarding how our body’s systems respond to various foods and environmental situations. The head of Stanford University’s genetics dept recently appeared on Fox news and indicated that a large sample of people all over 100 yrs of age were tested and 5 genes were discovered in this population which are different in this group from the general population. Gene modificaton could add about 30 years to average age he said. One of the oldest members of this group of codgers, he said, had been smoking for 116 years. Living a “clean” life may get you an extra year or two in the nursing home but your genes determine your true longevity. They also determine how you will respond to various medicines and therapies.
Thanks for the article, Mr. Hansen. The question I have is why do the supporters of a low-salt diet say–and this is important: not our speculations, but why do they say–they support a low-salt diet. If they are honest they will admit there is at least some evidence that a low-salt diet is harmful to the general population. In the face of this evidence, why are they still in favor of a low-salt diet for everyone?
Will they say that it just intuitively feels like people eat too much salt even before they look at the scientific evidence? If they say it is save thousands of lives per year, ask them: where is their evidence of that? Yes, some people have looked at some of the results of some studies and inferred that reducing salt in hypertensive individuals might make some small difference, but that is a long way from having a reason to reduce the salt intake of everyone. Will they say unless everyone is told to reduce their salt, those hypertensive individuals will not take it seriously?
It is important to understand what opponents of salt say about their own motivations if we are to make arguments that they will listen to and consider.
Reply to Daniel Wisehart ==> You have hit on one of the major mysteries of Science Wars in general.
Why — if there is such clear evidence of controversy and uncertainty — does one side continue to insist that the science is settled, that “the facts are clear”, and everyone should ignore all contrary evidence and opinion?
Hopefully, this series will help us to collectively discover some of the underlying reasons.
Interesting, I think one aspect of this jumps out. I suspect you will find that the “protectors” of whatever the existing “scientific” dogma is, have to some degree both their pocketbook and their reputation on the line, often in the form of Government funding.
A question from an inquiring mind.
Would it be beneficial to switch some of your salt intake from NaCl to KCl?
From what I read, I believe this is not necessarily a good replacement for salt NaC1. Unless your physician has approved this, even then I am doubtful.
http://my.clevelandclinic.org/services/heart/prevention/nutrition/food-choices/salt-substitutes
Here is a bit more information. Based on case evidence of an event.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1124926/
The balance is probably more important. Potassium in slight excess is more toxic than sodium in slight excess. The toxic chemical used for executions in the U.S. is potassium carbonate (which acts in two ways, potassium in excess interferes with nerve electrical impulses and the carbonate changes the pH of the blood outside the very narrow limits for life).
Reply to Richard of NZ ==> “Until 2009, most states used a 3-drug combination for lethal injections: an anesthetic (usually sodium thiopental, until pentobarbital was introduced at the end of 2010), pancuronium bromide (a paralytic agent, also called Pavulon), and potassium chloride (stops the heart and causes death). Due to drug shortages, states have adopted new lethal injection methods”….latest methods here.
Jeff
Eat bananas and accept that the radiation is “natural potassium”
The author has started to mine a very rich vein of controversies, and it will be fun to read how it progresses. Risk from radiation exposure, low level air and water polution effects, second-hand cigarette smoke, the cholesterol and sat-fat wars, the body-mass-index controversy, organic vs inorganic food, endocrine disrupters, pesticides, all sorts of evil chemicals, etc. You will be able to write about this for a long time. Mr. Taubes has made it into a career.
At the most fundamental level, these issues involve the human body’s reaction to small amounts of a substance. Most of the time, most human bodies deal with exposures to these “insults” and you never see how it is done. The problem arises when the body either does not recognize the insult and deal with it, or reacts to it is a way that is harmful. However, there may be times when the insult is actually a benefit to the body. This phenomenon is particularly difficult to identify and quantify.
As a result, acitivites to identify and mitigate the harm done by these substances are based on epidemologial studies of various sorts of populations. Some of them are heterogeneous, some homogeneous, but in no case is it possible for the researchers to perform a real scientific trial, where the same experiment is done on the same subjects under different conditions and levels of “insult”, to verify the hypothesis. It is utterly impossible to strictly reproduce, within the limits of the measuring technique, the results of any epidemological study, much less perform a confirmatory experiment. No one can make reproducible predictions of how any individual will react to the “insult”, because some will shrug it off, some will get sick or die, and some will actually get better. The researchers cannot identify which category individual people will fall into. They only predict the results for large populations, and even then, there are large uncertainties.
Human bodies are complicated, and our understanding of how they work is limited.Small doses and the concept of risk are very difficult for the human mind to deal with. it all comes down to those who have the most convincing, or the scariest stories. (This is where the “Precautionary Principle” come in.)
So, the uncertainties in these activities are huge, as are the controversies. The public health industry has a strong vested interest in pursuing them, because it builds empires and careers. They only care about overall population health care. If some people are harmed by the intervention, then they don’t care because they have calculated (note that this is a calculation, not an enumeration of any real dead bodies) nthat the overall outcome will be positive. I like to say that studies and activies like these are only of interest to governments and insurance companies. They only apply to large populations, as a whole, and only governments and insurance companies care about populations as a whole. Everyone else cares about specific individual people, not populations.
This series will be fun.
Reply to rxc ==> You are right about several things:
“Human bodies are complicated, and our understanding of how they work is limited.” Absolutely correct.
“The public health industry….care[s] about overall population health care.” The Public Health viewpoint, powered by misguided epidemiology, leads to many amusing, if harmful, public health stances, such as “If every one could lose 5 pounds, it would solve the obesity epidemic and improve public health” on the basis that millions of excess pounds of body weight would be lost. Absolutely nonsensical, but commonly preached by public health officials.
What can go very wrong with a “Low Sodium = 2000 mg Na /day Diet”? Sweat!
Especially for very active, working, or exercising people/athletes/children a “Low Sodium Diet” is dangerous in terms of Low Blood Pressure and Hyponatremia.
Each Liter of Sweat contains about 2000 mg Sodium, which needs to be replaced throughout the day along with each Liter of lost water. People usually know enough to replace the water because they get thirsty and therefore replace their lost effective Blood Volume by drinking fluids containing water. This takes care of the potential Low Blood Pressure problem which can result from effectively losing Blood Volume by sweating.
But to also keep from developing Hyponatremia [low Sodium concentration with possible Cerebral Edema and Death] the lost Sodium must also be replaced – along with, but usually after starting with “free water” replacement, because more water than Sodium Chloride = NaCl = “Table Salt” is lost by sweating, as compared to normal body fluid concentrations: ~2/1 = Water/Salt is lost through sweating.
One teaspoon of Table Salt [Sodium Chloride = NaCl] contains ~2,300 milligrams (mg) of Sodium.
I add ~1-2 tsp Table Salt to my food/day because I exercise, sweat a lot, and like it. I would start to think about using less Salt overall if I had High Blood Pressure, just to see if that would cure it or help in lowering it. Otherwise, fageddaboudit!
Agree.
I have always had marginal levels of sodium in my blood. The problem is that in summer or any time I exercise to the point of perspiring, I can get into ta hyponatremia condition. Maybe I lose more salt than most. The straps on my bike helmet turn white after a hot weather ride. Hyponatremia has put me in the hospital twice. Now, I know to add salt to all my food and drink in warm weather. I typically add 1/8 teaspoon to each 24 oz water bottle, and avoid drinking plain water on my rides. I make it a point to add salt to everything according to what tastes right. In the old days, before sodium levels in food were reduced, I never had this issue and never added salt to anything. Too little sodium can kill. Normal sodium levels are 135 to 140 (forget the units). My levels are always 135 or lower no matter how much sodium I take in. The first time I was in the hospital, prior to learning about hyponatremia’s dangers, my level was 123.
The directive to lower sodium should be taken with a grain of salt. Everyone is different and general guidelines might not be right for you. If you regularly exercise, look for the signs of chronic hyponatremia. Lethargy, insomnia, confusion, depression, poor short term memory, general weakness.
I have pretty strong opinions on this. I had a friend die from low saline levels.
When I would take him to the hospital he would be like a stroke victim (there were several episodes). A salt level of 100 basically turns your brain off.
He was convinced he had to eat “healthy”. A mandatory addition of chips and salsa to his diet would have saved him.
Reply to PA ==> I’m sorry your friend died due to accepting bad nutrition advice — I tell my friends that they need to take a general human physiology course online to prevent their being fooled into endangering their health by following idiotic food fads.
Your example is precisely what Mente and others are trying to prevent.
My brother in his 40s was very fatigued and fainting. I asked about his diet. He and wife ate hardly any salt. Turns out it made his blood pressure too low. I told him add salt to diet. He did and completely recovered.
Had he gone to a doctor, the first thing would be to check his blood pressure, And the solution would’ve been found there. As I said before, there is an optimum range of daily sodium intake. Taking too much or too little is just as bad.
I had to go through a delicate balancing act at one point in my diet. I originally started because I was overweight and on blood pressure meds. As my weight and blood pressure came down, the blood pressure meds had to be cut back just right to match.
Reply to Craig Loehle ==> Yes, we are seeing many personal experiences of harm from diets too low in salt.
People should have a personal physician, who should be a friend and know you, and get regular (depends on age) checkups, which include BP readings.
A relation of mine was advised by her doctor to increase her salt intake (she too has a health food predilection) because of BP too low. Perked her right up.
Even better, now that they’re cheap, get a home BP meter and use it regularly. Get to know what your diurnal BP range is. Get a good physician (MD or DO, doesn’t matter or didn’t … it might now) and pass that data on. It may give you a few more days to walk in the sun.
Some additional thoughts on scientific controversies: https://insuspectterrane.com/2015/03/18/its-controversial-2/
Thank you for an informative and dispassionate article. I hope more people become aware of this important issue.
I am probably in that subgroup of 10-15% who are salt-sensitive. While I don’t believe in government control, I think more should be done to inform people how much sodium is in food. Processed food and restaurants are the big offenders. I read nutrition labels, and am sometimes shocked at how much salt is used. As we all know, the “serving size” is almost always ridiculously small, as in “1 cup” of a common food such as cereal or pasta. Who eats just ONE cup? A six year old? Yet, some processed foods contain over 2,000mg of sodium in one “serving”! While I support public pressure to end oversalting foods, I firmly want to avoid making it a government mandate.
I am an older son of parents who left me with genetic predisposition to heart and kidney disease, and obesity. In my late 30s I was told my BP was too high, but I didn’t pay attention. I began suffering at-rest angina at age 53 and had stents implanted in 2001 & 2005. My cardiologist told me I had fairly aggressive heart disease. But my total cholesterol was not even 200! Nevertheless I altered my diet to lower cholesterol and sodium, and began taking anti-hypertensive and vasodilating medications, along with a statin. I also began a serious exercise regime. In 15 years I’m still pretty much the same weight I was long before I had symptoms, but my cholesterol and BP are well controlled now. I don’t suffer from angina, and though I’m not as able to exercise as before I still go to the gym and bike several miles 3x a week.
I can’t wait for your series on Climate Wars and “Second Hand Smoke”. ASIDE: I was a C-SPAN junkie in the 80s – 90s and watched the congressional hearings that led to targeting second-hand smoke as a public hazard. The government cherry-picked studies that showed a link, and ignored many others and serious evidence that disproved it. Same with DDT, where a group of eminent senior scientists presented convincing evidence that there was questionable science behind the ban.
Again, thank you for your efforts.
Two extra points:
1 – add under “What We Know About Dietary Salt:” the following point:
“Humans have very effective bio-systems which excrete excess salt.”
2 – Has anyone critically examined the assertion “High blood pressure (BP) is associated with cardiovascular disease and risk of premature death.”?
Reply to Dodgy Geezer ==> As for your point #2, there is really no doubt that, in an epidemiological sense, that “High blood pressure (BP) is associated with cardiovascular disease and risk of premature death.”
The key word is “associated” and key context is “epidemiological”.
Epidemiology, as a field of science, is incapable of discovering causes. It can only discover associations.
The statement only means that in the population-wide sense, people with high BP are more likely to have cv disease and suffer premature death than those with normal BP.
Mistaking these epidemiological associations as “causes” results in lots of misguided public health measures — the thinking being that reducing things associated with cv disease will actually reduce cv disease incidence.
By ‘critically examine’ I meant that someone should look for cause/effect and association with other phenomena. For instance, raised blood pressure is associated with old age – is it simply a natural progression like baldness or wrinkly skin? I’m pretty sure that going grey is strongly associated with reduced life expectancy – perhaps we should have hair dye prescribed?
Reply to Dodgy Geezer ==> Increasing age does generally include rising BP. It is one of the aspect of human physiology that leads to the finding that “high BP is associated with increased risk of death” — as older people die more often than younger people.
Good article but would also be nice to cover some areas of “cheap fix” suppression by NIH and FDA in their support of pharmaceutical companies like this one:
http://www.iflscience.com/health-and-medicine/scientists-regenerate-leg-muscles-pig-bladder-tissue/
salt is not sodium alone …
I personally consume about a heaped tablespoon of trisodium citrate every day.
It’s TRIsodium, so three for the price of one.
Actually, it’s a powerful buffer and I started to consume it for the sake of providing symptomatic relief for a UTI a few years ago. Then I discovered that I felt better generally if I took some daily.
If you see me posting here, then be assured that I am not dead yet.
I also cure chicken in sodium bicarbonate. Before cooking it. Another experimental project of mine.
And I eat generous amounts of salty red chilli sauce on everything that I eat.
Plus, I’m a fan of sauerkraut. (Cabbage pickled in salt).
So, I’m not going to suffer from a sodium deficiency anytime in the near future.
But, I figured that my ancestors evolved in a salty ocean, so we have probably by now evolved some mechanism by which we cope with exposure to sodium.
I’m not really all that interested in what modern nutritional science has to say about my preferred diet.
As far as I can see about 99% per cent of nutritional science is bunk.
As is 97% of climate science, of course!! 🙂
Would you please post a recipe or link to a recipe for sodium bicarbonate chicken? This sounds very interesting…
Hi Peter, Thanks for your interest.
I’ve been cutting down on carbs and increasing my intake of protein and fat. (After my partner read Taubes, about 5 years ago).
I also do a lot of exercise and physical work, so I wanted to create an easy to digest, cheap source of nutrients and calories.
I noticed that meat shrinks and becomes tough (and hard to digest) when cooked in acid conditions and so I decided to see how it would behave when first soaked in an edible alkali.
It’s a work in progress.
Currently I buy about 4 kilo of chicken thighs and mix up about 30grams of Sodium Bicarbonate in about 150ml water.
I also add meat tenderizer (papain) or bromelain.
I throw all this into a tough plastic sack and seal it with a cable tie.
I leave the sack in the fridge for several days. Then – I transfer it to a big pan and rinse it with a few changes of fresh water and then bring it to heat, just covered with more fresh water.
What happens – is rather than shrinking, the pieces of chicken expand.
I leave it cooking on a low heat for most of a day.
It’s the tenderest chicken I’ve ever had. Which was my intention.
I’ve only been doing this for a few months and I’m constantly improving the process.
I have googled for more information with little success.
This subject has been investigated by food scientists – but I have not been able to find anyone who is presenting this as a recipe for home cooking.
Here is a scientific paper produced by some people who appear to have made a similar discovery!!
http://wwwf.imperial.ac.uk/blog/physics-of-cooking/2015/02/16/the-effect-of-sodium-bicarbonate-on-the-water-holding-of-pork-loin/
I would wonder a little about your intake of citrate, but if the current level does you good then good for you. Citrate chelates Ca and Mg in soluble but non-ionised forms, making them unavailable to the body. This has the potential if taken to excess of possibly causing decalcification of the bones, or even acutely tetani.
Like so many things be careful of excess.
Reply to indefatigablefrog and Richard of NZ ==> Trisodium Citrate has medicinal uses and is used as a food ingredient. It makes a good descaler for boilers too. It is good advice to be careful of excess when dealing with any kind of substance being self-prescribed as a dietary supplement.
Thanks, I hadn’t got that far in my analysis. I like my grasp of food science, like I like my citrate – weakly basic.
I’d be more concerned about consumption of oxalates and phytates.
Which are widespread in the current “scientifically recommended diet”, in all manner of “healthy natural wholefoods” from unfermented soy, to wholegrains, to lightly steamed veg. i.e. everything that we are being advised to eat instead of meat.
Phytates and Oxalates form insoluble chelates with minerals stolen from the body.
That’s my weakly basic understanding. So I shun most currently popular non-traditional “health food”.
I seem to be thriving on my daily drink of citrate and citric acid (to taste). I actually enjoy it.
But, I will take heed of your warning and look more deeply into the potential long-term consequences.
So, thanks.
(P.S. Until a few years ago, I had become pretty feeble and frequently unwell after years of a conventionally recommended high carb, high fruit and veg “healthy diet” – I have experienced a complete turn around since adopting a diet of mostly meat, eggs and a minor dairy component.
I now feel strong again and have good steady energy levels.
I would prefer this condition of living – even IF it shortened my life due to a premature cardiovascular catastrophe!!!)
Thanks for a very interesting article. Others on this thread have pointed out other areas that will play out in the same way (pesticides, second hand smoke, etc) Of course the amount of damage done to medicine by the lumping together of all occurrences of cancer to smoking would be interesting to read about. I recall a fellow passing away from prostate cancer who’s family was told the cause was his smoking (a practice he had stopped 40 years earlier) His was a “smoking related” cancer death no matter what else may have transpired in the intervening 40 years.
Thanks for the summary and overview. As or after this series progresses, I’d love to see some discussion about the “emotional” attachments to various positions by general public impacted by the “science.
For understandably selfish reasons I want the best information pertinent to me about salt and my health and am hopeful that I am avoiding emotional attachments to one view or the other. For years I understood it to be important to limit salt intake. I never added salt to anything and avoided processed foods (Though I’d eat what was good at social gatherings and restaurants.) My tastes changed a lot and I found a lot of food too salty. Lately I’ve heard differing perspectives and as my blood pressure and health is fine, I’ve been adding some salt to my diet. I don’t have an emotional attachment either way as far as hoping one side is correct or not. I want to do what’s best – whichever that is.
I’d like to say that is my stance towards every scientific controversy and I would hope that would be the general stance for most of the public. But I wonder, do we become partisans due to things like our distaste and annoyance for the smug/obnoxious/dogmatic defenders on one side or the other?
Reply to aplanningengineer ==> I suggest reading the Mente study at the links here.
Thanks Kip. The study is supportive of where I’ve landed over the last year or so – believing that moderate salt intake is better for me than low sodium intake.
My “best guess” is that the Mente conclusions will be born out in time, but I’d change my opinion in a heartbeat with no angst if good evidence emerged to the contrary.
study 1:
morbidly obese people on a reduced salt diet have reduce heart attacks, therefore everyone, even healthy people should eat less salt.
study 2:
morbidly obese people on a increased digitalis diet have reduced heart attacks, therefore everyone, even healthy people should get more digitalis.
The American Heart Association – isn’t that the same organization that has been warning us of the dangers of dietary cholesterol for the past half-century?
Yet another example of the real dangers: politicization of science. But nobody wants to learn.
Personal hypothesis re: preferences for salty v. no-extra-salt foods.
People who love the taste of salt have body physiology that is adapted to that level of intake. Their body’s are conditioned to handling that level of salt intake and, as a result, are physiologically set to “expect” such intake and to excrete any excess so as to maintain the internal milieu (homeostasis). Those individuals that can not tolerate the taste of salt, have the opposite problem. Their systems are set to retain what salt they need and–should they ever need to “find” extra salt in the environment–to be able to sense its presence.
I suspect that one of the ways the body accommodates these diametrically opposing–and possibly varying during one’s life– interests, is by adjusting the sensitivity of the salt-receptor taste buds accordingly.
So those who eat a lot of salt have tongues that are relatively insensitve to NaCl, and thus such people love anchovies and use a lot of exogenous salt–to maintain the body’s salt in the face of the “expected” rate of loss. On the other hand, those who have exquisitely salt-sensitive taste buds, are already optimized to conserve salt and can get their needs met by the other foods they seek out in their “natural” diets.
Personally, I love salt. Indeed in the past, I used to salt everything before tasting it. I would salt a steak and then still find the need to salt each bite in order to adequately “taste” the salt. At one point, I decided to reduce my salt intake in deference to the “Received Nutritional Wisdom.” I found, that after a while as my body adjusted to the new “salt-intake environment,” I was able unable to tolerate the salt content of foods I used to enjoy (such as canned tomato soup), and overall my salt level “preference” adjusted to the new intake.
Thanks for the enjoyable essay, Kip. Best wishes for great success in life’s ongoing battle that we all face in maintaining our health as we age.
Those low-salters seem just as bad as global warming consensususts – even up to their political moves. Salt just happens to be a nutrient and nature has equipped us with a device for determining how much we need – taste buds. Some facts they left out that could shine light on the situation. It is well known that different national diets use different amounts of salt. Thus, for example, Americans eat about six grams of salt a day while the Chinese eat eight. I have not heard anything about how this relates to relative health, hypertension, etc of these two nations which these salt professors study.
It’s my hypothesis that we need so many “experts” to tell us what to eat today because so many people no longer have FAMILIES worthy of the name capable of handing down traditional food “wisdom.”
Most American’s iodine intake depends mostly on salt. Low iodine can cause
hypothyroidism and weight gain. Low iodine is associated with breast cancer,
some other cancers, and low IQ babies.
http://www.naturalmedicinejournal.com/journal/2014-06/iodine-and-cancer
https://rosiepope.com/2015/08/31/smart-baby-iodine/
I am still an athlete though I am a little old to compete, and I eat nothing
low fat. There is satiety in fats.
Episodically, my wife is a nurse, and her friends who work in the ER say
that there has been an increase in admissions in the summer due to electrolyte
imbalance, after Michelle O advised people to reduce salt intake.
I have wondered too about the increase in sea salt usage which is not iodized, contributing to low iodine intake.
Salt is good for you. Here is the key quote:
‘In a multivariate-adjusted model, those who consumed less than 3000 mg of sodium per day had a 25% increased risk of all-cause mortality and cardiovascular events compared with those who consumed between 4000 mg and 5990 mg/day (reference group).’ [1]
Please read the following. You will also enjoy Dr. Kendrick’s other blog posts:
https://drmalcolmkendrick.org/2014/05/13/salt-is-good-for-you/
“One of the most pervasive and stupid things that we are currently told to do is to reduce salt intake. This advice has never been based on controlled clinical studies, ever. Yet, as with the cholesterol myth, the dogma that we should all reduce salt intake has become impervious to facts. I find that the ‘salt hypothesis’ is rather like a monster from a 1950s B movie. Every time you attack it with evidence it simply shrugs it off and grows even stronger.
Very recently, a study was done in Australia looking at salt intake. Actually it looked at sodium intake, not salt intake. I find this interesting, as no-one that I know eats sodium. In fact, it would be interesting to see someone try. To quote from Wikipedia
‘Sodium is generally less reactive than potassium and more reactive than lithium. Like all the alkali metals, it reacts exothermically with water, to the point that sufficiently large pieces melt to a sphere and may explode; this reaction produces caustic sodium hydroxide and flammable hydrogen gas.’
Consuming two grams sodium would likely cause you to explode, splattering sodium hydroxide over the walls. Along with various organs and other body parts.
So why do people talk about sodium consumption? I have never really worked this one out. But it does make things rather confusing. The latest guidelines suggest we should consume less than 2300mg of sodium a day, even as low as 1500mg. Go on, try it. Any idea how much salt (NaCl) that would be? Any idea how much salt you consume every day? No, thought not.
Yes, we have been given guidelines that are totally meaningless, and impossible to follow. In fact 2300mg of sodium is roughly 6000mg of salt (NaCl). So why are we not advise to eat six grams of salt a day? I have no idea. Perhaps someone can tell me. What is this sodium nonsense? [Not that anyone has any idea what six grams of salt even looks like poured out of a salt shaker – I know, I have tried this several times.]
Of course, when I started looking into this area, I went at it sideways. If we eat salt we are eating both sodium, and chloride. You cannot have one without the other. So I became interested in the chloride issue, not the sodium. We are always warned about sodium, but no-one ever mentions chloride levels. Is there any evidence that high chloride consumption is bad for us?
This is an area mostly defined by silence, and zero research. But I have found a few papers looking at chloride levels in the blood and, guess what? They have all found that a low chloride level is associated with a higher mortality. Here is one such, entitled ‘Serum chloride is an independent predictor of mortality in hypertensive patients.’
‘Low, not high Serum Chloride- (<100 mEq/L), is associated with greater mortality risk independent of obvious confounders. Further studies are needed to elucidate the relation between Cl- and risk.’ (view here)
There you go. Having a low chloride level makes it more likely you will die early. Yet, having a high level of sodium consumption makes is supposed to kill you? And you cannot eat sodium without eating chloride at the same time. Go figure. You mean you can’t?
Anyway, to return to the, not yet published Australian study, here is what they found.
‘In a multivariate-adjusted model, those who consumed less than 3000 mg of sodium per day had a 25% increased risk of all-cause mortality and cardiovascular events compared with those who consumed between 4000 mg and 5990 mg/day (reference group).’ [1]
The guidelines tell us to eat less than 2300mg of salt. At this level, if we use the Australian data, overall mortality will be increased by 25%. Excellent advice then. And this is not just one contradictory study. Several other trials have clearly demonstrated that reducing salt intake significantly increases mortality in high risk patients. Particularly those with heart failure, where it would be expected that salt reduction would have the greatest benefit. Yet the trials showed the exact opposite.
As explained in the Journal Stroke. The section I have quoted below is taken from a reply to an article entitled “Reducing Sodium Intake to Prevent Stroke: Time for Action, Not Hesitation” In this article Appel, the author, argues strongly that we must, absolutely must, reduce sodium intake. In reply, three cardiologists make the following points:
‘In regards to patient-oriented outcomes, Appel dismisses randomized trials in patients with heart failure as irrelevant because of the unconventional treatment approach of the investigators. Yet these trials—showing increases in hospitalizations and mortality with low-sodium intake versus normal-sodium intake—tested identical diets in intervention and comparison arms with the only difference being the level of ingested sodium (making these trials more relevant than DASH-Sodium and other trials Appel cites). Also, Appel fails to cite 3 relevant heart failure trials, all consistently show harm with reduced sodium intake.’ [2]
In short, Appel, along with most ‘experts’ in this area had dismissed evidence he did not like.
The simple fact is this. If you strip out all the data on salt consumption there is considerably more, and considerably more powerful data, suggesting a strong link between low salt consumption and increased mortality than the other way around.
In reality, you can eat just about as much salt as you can stand – without harm. (Unless you have damaged kidneys and/or very high blood pressure)
How can I possibly state this? Well, a very wise Swedish professor pointed something out to me a few years ago. If a patient is very ill in hospital and cannot eat, or drink, they will have a drip put up to replace fluids. This very often contains 0.9% NaCl. Or nine grams of salt per litre. Quite often the patient will have two litres of this replacement fluid a day – which is (as you may have figured) 18 grams of salt.
So, we quite happy to give critically ill patients 18 grams of salt per day to help them get better – which has no discernable effect on their blood pressure, or anything else. Yet we tell people that they cannot eat more than six grams a day. Ho, ho. You earthlings are so funny.
References (may require site registration or membership to access)
[1] http://www.medscape.com/viewarticle/824749?src=emailthis
[2] http://webappmk.doctors.org.uk/Session/1405533-8qblkO84E9hsUXe6OUa4-aoqmidt/MIME/INBOX/125637-02-B/Stroke-2014-DiNicolantonio-STROKEAHA.114.005067.pdf to be published soon
Reply to TedL ==>: Thanks for the additional input — there is a lot of evidence building for the anti-salt-reduction side.
Six grams is nearly a quarter of an ounce…quite a big pile.
“And you cannot eat sodium without eating chloride at the same time.” – how about Monosodium Glutamate, Disodium guanylate, Disodium inosinate – widely used “Taste enhancers”?
Ok, some basics, then a questioon I have not seen raised.
I am 66, healthy, and take no medication, suppplements, or whatever. I occasionally take some ibuprofen when I overdo physical activities. My BMI is 25. My blood pressure stays around 110/70. My cholesterol is higher than the guidelines, but the doc knows I object to statens, and I have no other risk factors for heart attack or stroke.
I regularly salt foods. Most people, even in these comments, seem to have no clue as to how salt interacts with foods. It is a flavor enhancer. For instance, it will make sweet foods, sweeter. Try a little on pineapple, grapefruit, strawberries, or watermelon, and see for yourself. It will add complexity to other flavors. It will increase the enjoyment of your food (if you have not been made to feel guilty for adding salt).
This article exactly confirms what I have gleaned from the literature over the past decade. Most people simply do not have to worry about their salt intake.
I eat everything (I control my weight via calorie counting. The answer for me is portion control). I’m sure I get WAY more dietary salt than the guidelines, and that leads to my question. I get an annual physical, including a full blood analysis. They ALWAYS show that both my blood sodium and chloride levels are in the normal range. Shouldn’t THAT be the measure of whether a person’s salt intake is too much or too little? We each have our own little ‘chemistry factory’ in our bodies, and I doubt if everyone absorbs/elminates/uses any dietary component the same way. I don’t think I’ve ever seen a study that tried to correlate blood sodium and chloride to health issues, but am sure there must be some.
Apologies for the multiple typos. I’m using a damaged iPad, and it frequently ‘stutters’ on some letters (especially on the right side of the keyboard).
Reply to Jtom ==> Your body is a self-regulating organic chemical machine. Sometimes these machines get “out of whack” and don’t regulate themselves.
The whole Salt Wars thing
sis about correlating blood sodium levels and urine sodium levels (a measure of sodium intake) to overall health outcomes.The problem, Kiip, is setting a standard maximum intake, e.g. 1500mg, for everyone. The relationship of dietary sodium to blood level sodium is not going to be the same for everyone. If a doctor told me to reduce my dietary sodium, for any reason, without even looking at my personal blood sodium level, I would drop him like a rock. What I am advocating is that no one should be told to reduce or increase anything in their diet unless there is evidence that that person’s chemistry is out of whack because of it.
Both the sodium and chloride levels for my wife are very slightly below the normal range. If she were to develop high BP, and the doctor advised her to cut back on salt, my first thought would be medical malpractice
Now my original question: how many of these studies looked at the actual blood sodium levels versus simply looking at consumption vs health outcomes? All of the studies I have read looked at diets or urine, calculated the salt intake, and correlated that to health outcomes. In my particular case, I would argue that high levels in my urine was meaningless, and would not manifest as a health problem because my blood levels were fine. Reducing salt consumption would be unnecessary.
And, Kip, does it not follow that if your body is failing to eliminate salt properly, it would result in sodium levels being high in the blood and low in the urine, giving a completely wrong result to this research?
Don’t worry about the salt as long as your blood pressure is fine.
You’ve just eliminated 70-85% of the population (depending on how you define high BP). You are correct, of course, but how could bureaucrats rule over us, and eventually tax us, if they admtted that?
Reply to jtom ==> An interesting point — the majority of these studies do use urine sodium excretion as a measure, either morning fasting urine (first pee of the day) or 24-hr urine (all of the pee of a day). In fact, the AHA’s only scientific criticism of Mente et al. is that the studies they reviewed used morning fasting urine results instead of the more accurate 24-hr urine method. Mente replies that studies had clearly shown that the once a day urine test correlated very well with the 24-hr method (which is true). The 24-hr method makes large scale studies nearly impossible or restricts them to persons who are institutionalized (hospitals, prisons, armed services) which skews results in unknowable ways.
Similarly, pulling blood samples every day and testing for sodium levels would restrict the participants to an institutional setting and thus not give us valid results about “free living humans”. Of course, that much blood work would make the study impossibly expensive as well.
“Serious sodium retention can cause edema in kidney failure, also it can worsen high blood pressure symptom.” Studies on salt restrict their cohorts to those who are healthy, and exclude persons with kidney failure or disease.
Overall, retained sodium is controlled for by the body by adjusting fluid volume — retaining water to offset retained sodium (salt) in order to maintain the correct =salinity of the body’s fluids overall.
Perhaps one of the doctor’s reading here can address your question more fully.
Didn’t comrade Bloomburg pull all of the salt shakers off of restaurant tables in NYC? When are you going to the essay called the Big Gulp wars? Lol. As the government takes over health care more and more of this crap is going to be the norm.
In full disclosure the Koch brothers are paying me to be a sodium denier.
How does one get in on that? 😉 Here I am being skeptical for free…
Reply to Logos_wrench ==> Bloomberg did start an action to reduce salt — the effort was often accused of being a proposed ban on salt shakers. Didn’t get passed, didn’t go into effect.
The latest is the salt shaker warning symbol required on fast food items with high salt content.
Shoddy science is, I sometimes think, more common than the other kind.
Especially if you think of “the misplaced certainty of assuming you know more than you do about the *question*” as shoddiness.
Especially when it comes to medicine. “The wrong question” is epidemic there, as exemplified by the “salt to control blood pressure” vs. “other, vastly more effective controls” example above.