Shaking up the Salt Myth: The Dangers of Salt Restriction

“In an era when dietary advice is dispensed freely by virtually everyone from public health officials to personal trainers, well-meaning relatives, and strangers on check-out lines, one recommendation has rung through three decades with the indisputable force of gospel: Eat less salt and you will lower your blood pressure and live a longer, healthier life.” Gary Taubes, 1998

 

In my last two articles, I discussed the history of salt in the human diet and the physiological need for salt. Many proponents of the Paleo diet suggest limiting salt based on evidence of low salt intake during the Paleolithic era. This limitation meshes with recommendations made by various health organizations, such as the USDA and the American Heart Association, who suggest limiting sodium to at least 2,300 mg per day and even as little as 1,500 mg per day. (1, 2) And if our Paleolithic ancestors ate a low salt diet, then it certainly must be healthy, right?

Not necessarily. Recently, evidence has been mounting against universal salt restriction guidelines. A low-salt diet may cause serious health consequences and higher overall mortality, especially in the presence of certain chronic health conditions and lifestyle factors. In this article, I will discuss scientific evidence that contradicts salt restriction recommendations, as well as potential health risks of consuming a diet too low in salt.

Serious health consequences of long-term salt restriction

While salt-induced hypertension is typically blamed as a cause of heart disease, a low salt intake is associated with higher mortality from cardiovascular events. A 2011 study in the Journal of the American Medical Association demonstrates a low-salt zone where stroke, heart attack and death are more likely. (3) Compared with moderate sodium excretion, there was an association between low sodium excretion and cardiovascular (CVD) death and hospitalization for coronary heart failure. These findings demonstrate the lowest risk of death for sodium excretion between 4 and 5.99 grams per day. (Figure 1.)

Figure 1. Estimated 24-Hour Urinary Excretion of Sodium and Composite of Cardiovascular Death, Stroke, Myocardial Infarction, and Hospitalization for Congestive Heart Failure

Another 2011 study confirmed this observation; not only was lower sodium excretion associated with higher CVD mortality, but baseline sodium excretion did not predict the incidence of hypertension, and any associations between systolic pressure and sodium excretion did not translate into less morbidity or improved survival. (4)

Low salt diets contribute to an increase in hormones and lipids in the blood. A 2012 study in the American Journal of Hypertension found that people on low-salt diets developed higher plasma levels of renin, cholesterol, and triglycerides. (5) The authors concluded that the slight reduction in blood pressure was overshadowed by these antagonistic effects, and that sodium restriction may have net negative effects at a population level.

In addition, low sodium intake is associated with poor outcomes in Type 2 diabetes. A 2011 study study showed people with Type 2 diabetes are more likely to die prematurely on a low-salt diet, due to higher all-cause and cardiovascular mortality. (6) Additionally, a 2010 Harvard study linked low-salt diets to an immediate onset of insulin resistance, a precursor to Type 2 Diabetes. (7) These studies call into question the appropriateness of guidelines advocating salt restriction for patients with Type 2 diabetes.

Restricting salt is also problematic for athletes, particularly those participating in endurance sports. (8) Recent studies have shown that endurance athletes commonly develop low blood sodium, or hyponatremia, even in the absence of cognitive symptoms. In the 2002 Boston Marathon, it was found that 13% of 488 runners studied had hyponatremia, and studies of other endurance events have reported the incidence of hyponatremia to be up to 29%. (9101112)  While the majority of these sodium deficient athletes are asymptomatic or mildly symptomatic with nausea and lethargy, severe manifestations such as cerebral edema, noncardiogenic pulmonary edema, and death can occur. (13) It is extremely important that athletes engaging in high intensity or long duration exercise be sure they adequately replace the salt lost through sweat.

Salt restriction may be especially dangerous for the elderly. Elderly people with hyponatremia have more falls and broken hips and a decrease in cognitive abilities. (1415) Hyponatremia is a common finding in the elderly, with an especially high prevalence in those with acute illness. (16) This is another population at risk for serious health consequences due to universal sodium restriction.

 Why is the government still recommending salt restriction?

Conventional healthcare experts have been recommending salt restriction ever since the 1970s, when Lewis Dahl established “proof” that salt causes hypertension. (17)  In his research, he induced high blood pressure in rats by feeding them the human equivalent of over 500 grams of sodium a day; 50 times more than the average intake in the western world. (181920) Dahl also invoked evidence that cultures consuming higher levels of salt tend to have higher blood pressure than those who consume less salt. (21)

Figure 2. Correlation of average daily salt (NaCl) intakes with prevalence of hypertension in different geographic areas and among different races, from Dahl, 2005

However, when Intersalt researchers investigated this possible association, while controlling for confounding factors, the correlation between blood pressure and salt intake almost disappeared. (2223) For some reason, this contradictory evidence is still being used today to justify restricting salt intake.

In 1998, Gary Taubes wrote an article for Science magazine highlighting the clash of public policy with controversial scientific evidence for salt reduction. (24) He described how most of scientific discord over salt reduction has been overshadowed by the public attention given to the benefits of avoiding salt.

As Taubes explained over a decade ago, “the data supporting universal salt reduction have never been compelling, nor has it ever been demonstrated that such a program would not have unforeseen negative side effects.” The 1988 Intersalt Study, designed to resolve contradictions in ecological and epidemiological studies, failed to demonstrate any linear relationship between salt intake and blood pressure. Now, in 2012, we have data that suggests long-term salt restriction may pose serious risks for much of the population. Yet major health organization guidelines still recommend the restriction of salt for all Americans, regardless of blood pressure status.

In short, there is a healthy range of salt consumption for most people. When eating a whole foods diet, most people tend to consume an appropriate amount of salt simply due to an innate preference for saltiness. In fact, the consumption of salt around the world for over two centuries has remained in the range of 1.5 to three teaspoons per day, which appears to hold the lowest risk for disease. (25)

Our bodies may have a natural sodium appetite through which our ideal salt intake is regulated. By following a whole foods, Paleo diet, and eliminating processed foods, excess sodium in your diet will be drastically reduced. Thus, you can be confident in following your own natural taste for salt when adding it to your food during preparation. In other words, there are few reasons to deprive yourself of salt!

In my next article, I will discuss the conditions in which salt reduction may be warranted, and nutrients that may be more important than sodium in controlling blood pressure and promoting overall health.

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Comments Join the Conversation

  1. says

    Great article. My mother suffers from terrible hypertension and several years ago, was prescribed a low-sodium diet. My mom was never one to eat much in the way of processed foods, the healthier the food, the better, so she took to this new diet with gusto. I watched as her health declined rapidly – her heart problems worsened, there were frequent mini-strokes, and memory was suffering. We didn’t know why this was happening. Years later, one doctor finally has the common sense to note that she was suffering electrolyte imbalance and mom was subsequently put on a higher sodium diet. Mom now adds fleur de sel religiously to her meals and her health has improved. She still suffers from hypertension, but she is much more stable and her memory has improved (despite the strokes).

    I now warn friends about recommending a low sodium diet to others. It’s better for them to recommend eliminating processed foods.

  2. Richard Jones says

    I DEFINATELY crave salt on some foods, since cleaning up my food palate. The body demands, the body receives. :-)

    I have some Qs about gall bladder, for you Chris, where can I send them?

    -Richard

  3. Mollie Player says

    It’s so amazing how long it takes for conventional advice to go out of favor. People are STILL talking about lowering fat … HUH???!!

  4. says

    Great post. I’m very interested in reading what you have to say about other nutrients involved in BP regulation (magnesium? potassium?) because I have high BP with NO other issues – i.e. I am lean, very physically fit, with normal blood sugar, cholesterol, everything. It’s just the BP that is elevated. Do you think tall people have higher BP because it takes more to pump that blood to our (farther out) extremeties?? :)

    • Ben says

      Great question, I’m personally very interested in this because I’m in much the same situation. Lean, eat paleo, health metrics appear good except BP. And also tall!

      In particular, there seems a lot of talk of the ratio of sodium to potassium in the diet being a (or the) key factor in blood pressure disregulation.

      Do we have a sense at all of how much sodium is taken in by hunter gatherer societies?

    • Philomina says

      I am in the same situation as Mary and Ben. The only thing I am having is hypertension. I am not tall. I have even lost some weight and nothing is happening. All my numbers are great. No high cholesterol, AIC is good, I mean everything is good except the blood pressure. I just started increasing my consumption of celery because I read that it provides nitric oxide.

    • says

      I wouldn’t get wrapped up in any diet rules out there. Everyone is different and each person’s body demands different foods, ratios, nutrients, etc. in it’s own unique way. Subscribing to set diet rules and recommendations is like driving down a road blind folded. Sure there are some great general guidelines to follow such as eating whole natural foods and staying away from PUFAs, gut irritants, etc. But it’s important to listen to your body’s needs and follow through with them. If you’re craving more salt or carbs .. it’s a good idea to follow your intuition.

      • ChrisG says

        I have to disagree with the intuition approach. I cut back on salt because I was eating it like a food unto itself. Routinely salting salty things..like cheese, and.eating salt by itself, etc. And apparently my body “needs” a lot of wine and pancakes too. With those sort of cravings, a few rules can keep things from getting crazy…

        • says

          Right, if you find yourself indulging in processed food at every meal or binge drinking, you’ve probably got some other issues to work out. Every now and then, in my opinion, it can be very beneficial to let yourself go and destroy a stack or 2 of pancakes or order that large pizza and take it down followed by some good craft beers. That can actually do wonders mentally.

  5. says

    Chris, this is overall good advice – but most of the endurance athlete studies that you cite acknowledge that plasma sodium levels were often maintained, but the issue was overconsumption of hyoptonic fluids – in other words – drinking too much water and/or sports drinks during the event, effectively diluting the body’s fluids. Noakes himself will admit that sodium supplementation is not necessary, even for long, hot and humid events, due to endogenous sodium stores and decreased loss via kidney excretion.

    • says

      Good observation. I believe over consumption of fluids, particularly water, is actually a much bigger problem than most think. It’s under most people’s radar. Matt Stone has done a great job reporting on it and what can be done about it. Dilution of the fluids at the cellular level causes people to dump water – causing symptoms such as a very strong urge to urinate, anxiety, adrenaline rush, light headedness, fatigue, etc. This can be a devastating problem for people who have metabolic issues, hypothyroidism, “adrenal issues”, etc.

      People should check out this interview with: http://180degreehealth.com/2012/02/mild-water-intoxication.

  6. says

    I’ve often wondered about salt. Since paleolithic man ate low amounts of sugar, wouldn’t it be similarly wise to reduce intake of salt likewise? Keep up the good work, Chris, very interesting.

  7. jackie says

    i personally eat a lot of himalayan salt because my blood sodium level is chronically low (maybe because of adrenals?), but i just listened to an interview of charlotte gerson, of the famous gerson cancer therapy, and she says NO salt, ever. she is super healthy at age 90 or 91. so i guess just as tyler above said, everyone’s different. :-)

  8. jackie says

    also, it’s weird, because even though my sodium levels have been low for the past few years, i didn’t crave salt and always had to remind myself to salt my food. hm……?? i crave sugar more.

  9. Dianaedd says

    Frequently, the elderly people who have low sodiums are sickly, taking a lot of meds including ones that lower their serum sodium (such as diuretics), so it may be a stretch to say that the low sodium causes their problems primarily.

  10. Greg says

    Good article. Those studies are still just correlations. For references 3-4, as well as the others you mentioned, sodium/electrolyte excretion is NOT synonymous with salt intake. That’s an important distinction to make because those studies only showed that sodium/electrolyte excretion has a “sweet spot” for CVD. For reference 5, the last thing any physician in their mind would do is to suggest increasing salt intake for hypertensives. The sodium/potassium balance may be the real culprit, among other possibilities…For references 6-7, diabetics obviously have to urinate more because of excess sugar in the bloodstream. A low-sodium diet in this case would obviously be the opposite of what is needed. According to TCM, the kidney-adrenal function weakens in old age, and salt acts to stimulate the kidneys. Therefore, the elderly do benefit from a moderate amount of salt and a low-sodium diet would be contraindicated.

    I must respectfully disagree with you about the salt/hypertension connection. According to TCM and Western Medicine, if you (or any other animal for that matter) consumes too much salt, it will most definitely increase your blood pressure, put strain on your heart muscle, and long term, it will damage your kidneys among other things. Fact is, the reason why the government imposes an upper limit of 2300 mg/day, as you mentioned, is that processed food is loaded with sodium, which is used as a food preservative. It is my understanding that Americans consume on average, way more than the recommended limit because of widespread usage of processed and junk food. The last thing anyone on a SAD diet should do is to increase their salt intake.

    Salt requirements vary widely by individual. But 1.5-3 teaspoons is quite high! In the long run, you risk numerous health complications. For those on a meat-centric paleo diet, salt intake must usually be higher to compensate for the excess of meat. Salt is alkalizing and lubricating and is therefore craved by those eating too much meat, which is what paleo entails. (There’s a reason why every steakhouse has a large salt-shaker on the table and Japanese people have been eating fish with soy sauce for centuries) TCM indicates as much. Whole, unrefined sea salt used in moderation in conjunction with a vegetarian grain/vegetable-based diet is beneficial, however.

    • Pone says

      You are not analyzing this correctly.

      First, my blood pressure when sodium is normal is 119 / 71. When I get low sodium my pressure jumps to 150 / 88. My pulse goes very high and I lose glucose control. So the first problem with your post is that you only look at what high sodium can do and you fail to address what low sodium can do. My low sodium went undetected by four doctors for three months and destroyed my health. I was on about 1/2 teaspoon per day.

      Second, you are committing the fallacy of designing the diet to treat the symptom without first understanding is the symptom the result of the diet. The hypertensive may be suffering because of low sodium. The correct solution for that patient is to normalize sodium levels.

      Here is how scary my low sodium became. If would walk for one hour low intensity and then drink water to satisfy thirst. But because of low sodium kidneys excreted all that water quickly. I would spend entire nights every hour getting up desparately thirsty and drinking, immediately urinating, never resolving dehydration. If would describe these symptoms to multiple doctors and not one could figure it out.

      It resolved immediately by adding salt to diet.

  11. says

    I have been on a no salt diet for some time, meaning no salt at all and i have to disagree with many things that are stated in this article. First of all the studies talk about a danger in a low sodium diet, but here the author is equating salt as the only source of sodium in a diet, implying that if one does not eat salt then one will not have enought sodium in their diet. This is definetly not true, as there are many good organic sources of sodium out there, celery being one example.. and humans are the only ones that apparently ‘need’ salt while most animals can go well without it.. plus salt is a mineral.. not organic source meaning the body does not assimilate it.

  12. coleman says

    i developed type 2 recently and was adviced to go on low salt diet. After six months my health started deteoriating badly,Problem with my vision, general weakness and also develop a huge appetite. Always having aches all over my body. I collapsed with driving one day and was ambulanced to the hospital ,to recomend low salt. I knew there was something wrong with my salt level. I told the doctor how i might need salt. Immediately i was given salt intravenously, i became o.k. I started adding salt to all my foods even my morning milk . I discovered after a week saltrying my foods. i don’t experience insulin surge again and i went to do my blood test and the diabetes symptoms all gone.
    I love this article of this writter. please tell the whole world that low salt diet is the cause of early death. The paleolthic people were never highly populated. May be because of low salt diet makes them to die young and also infertile. My wife has not conceived once since our 8yrs marriage living on low salt diet. A month of living on high salt diet gives her the conception she’s having now.

  13. steve says

    I have severe pain in my knees and hips and recently been getting cramps in my fingers and calves, I sauna almost every day, could my symptoms be caused by lack of salt due to sweating. I am male, 55, and otherwise fit and well. My G.P. is useless and just keeps saying “wear and tear” keep taking the pain killers, I’d rather have a cure. Can anyone help please?. steve

  14. says

    I can’t seem to find a link to articles you subsequently write on certain topics. For example, in this article you said, “In my next article, I will discuss the conditions in which salt reduction may be warranted, and nutrients that may be more important than sodium in controlling blood pressure and promoting overall health.” Is it possible that once you have written that article you could provide a link at the end of the previous article so that readers can follow the topic extensively? It would help immensely. Unless of course you already do and I’m just way too blind to see it :-)

  15. says

    You mentioned in the previous instalment that the potassium / sodium ratio may play an important role. I can’t help but wonder if a salt restricted diet is only detrimental when consuming small amounts of potassium as well. I don’t have time to check all the studies you referenced, but I wonder if that was the case for those participants. Someone that is exercising salt restriction but still sticking to low-sodium processed foods would most likely be not consuming a lot of potassium. Conversely, someone consuming whole foods (no salt added) will be getting lots of potassium while still not getting a ton of salt.

  16. Mike says

    Thank you for this. I’ve been on a low salt diet due to high blood pressure and I’m now going to start rethinking that. I’ve had aches and pains, have noticed my heart beating harder than normal, and have generally felt fatigued and crummy ever since starting on the diet. It now seems that low sodium may be the cause. I also found a very informative New York Times article about this topic: http://www.nytimes.com/2012/06/03/opinion/sunday/we-only-think-we-know-the-truth-about-salt.html?pagewanted=all&_r=0

  17. Andie Paysinger says

    During the 1960s I worked for an internist, Irwin Salkin, M.D., F.A.C.P., who wrote an article that was published in the New England Journal of Medicine and detailed problems seen in patients where salt restriction had been extreme.
    I typed the document but do not retain any of the details after so many decades, but find it interesting that recent, widely quoted, articles detail findings similar to those he noted some FIFTY years ago.

  18. pone says

    Someone please help me with the conversions here. The study Chris cites indicates 4 to 6 grams of salt excreted in urine per day is associated with lowest CVD risks. They are measuring by weight and not by sodium density? It’s a strange way to express this from urine measurement?

    By my calculations, one teaspoon of salt is roughly 4.8 grams of weight, so basically this study is saying that one teaspoon per day is a reasonable target intake?

  19. Nadine says

    Salt restriction + drinking large amounts of water (which is what is recommended) can’t be a good combination.

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