Shaking up the Salt Myth: When Salt Reduction May Be Warranted

As we have discussed in the last three articles in my series on salt, the evidence for universal salt reduction is weak and often conflicted. Across different cultures, dietary salt intake is at best weakly correlated with blood pressure or cardiovascular risks, and associated with poorer health outcomes at either extreme of salt intake, both low and high. As a general recommendation, it seems that salt restriction for most people may be both unnecessary and possibly harmful in the long run.

While most people have no reason to restrict salt to the levels recommended by various health organizations, there are a few health conditions in which lower salt consumption may be necessary, based on clinical and population data. Generally, these are people with serious health problems, particularly suboptimal kidney function, and the data supporting salt restriction in these individuals is somewhat controversial.

Salt intake with impaired renal function

For those who have high blood pressure, there is evidence that some hypertensive individuals have inherited salt sensitivity, thought to be caused primarily by impaired sodium transport in the kidney. (1) Our understanding of the salt-sensitivity mechanisms is still underdeveloped, but we do know that certain individuals are far more sensitive to fluctuations in dietary salt. Those individuals with this trait will have a significant blood pressure response to a high salt intake, and would likely benefit from reducing their intake of salt. However, it is thought that potassium intake can greatly impact these effects, and may even eliminate salt sensitivity symptoms. (23) In fact, salt sensitivity is dose-dependently suppressed when dietary potassium is increased within its normal range, so these individuals may benefit more from including ample potassium rather than limiting sodium.

Though the evidence is mixed, patients with chronic renal disease may have better outcomes consuming a lower amount of salt. (45) Those with impaired kidney function typically have reduced glomerular filtration rates and may have more difficulty excreting high levels of sodium. It’s possible that increased dietary salt exposure is toxic to the kidneys when sodium filtration is impaired, and may lead to unsafe levels of proteinuria. These patients need to be cautious about the amount of salt in their diet, though this is a highly individual situation, and largely depends on the type and severity of kidney disease.

High sodium intake may cause excess calcium excretion

Additionally, those who are prone to kidney stones may need to reduce their salt intake, as high sodium excretion also leads to a higher level of calcium excretion in the urine. (6) Again, evidence on this topic is mixed, but it has been demonstrated that excess sodium intake is associated with increased urinary excretion of sodium and calcium, and subjects who consumed the highest levels of sodium tended to have the greatest urinary calcium excretion. Higher calcium excretion may lead to kidney stone formation, particularly if fluid intake is inadequate.

Because of this increased calcium excretion with higher sodium intake, those with osteoporosis may benefit from a lower salt intake as well. (7) Increased losses of calcium in the urine, particularly in the context of low dietary calcium, could be problematic for those at risk for low bone density. However, a high salt intake is not believed to cause osteoporosis, and the potential osteoporotic effects of a high salt intake can be offset by an adequate intake of calcium and potassium.

Of course, it’s important to remember that the majority of these studies have been conducted on subjects consuming the standard American diet of sodium-laden processed food with a heavy emphasis on grains and a deficit of many important vitamins and minerals that we know play significant roles in hypertension, cardiovascular disease, and kidney health. If these sodium studies were conducted in a population consuming a nutrient dense Paleo-type diet, it’s possible the negative effects associated with a high sodium intake would be negligible. As we’ve seen, many of the cultures eating the highest levels of salt have less incidence of cardiovascular disease, kidney disease, and osteoporosis than Americans do. There is evidence that adequate consumption of other minerals may be far more important in blood pressure regulation and other related health outcomes.

Other minerals important for controlling blood pressure

There has been much research into the other dietary minerals that may play a role in blood pressure. The evidence has been mixed on whether certain minerals, particularly supplemental minerals, reduce blood pressure or risk for cardiovascular disease. However, epidemiological and anthropological data suggest that a diet high in certain minerals, such as potassium, magnesium, and calcium, may be beneficial in reducing high blood pressure.

Potassium is likely far more important than sodium intake in the control of blood pressure, as well as reducing the risk of hypertension, kidney stones and osteoporosis. (8) It is believed that human biological machinery evolved to process dietary potassium in amounts many times those of sodium, as Paleolithic man consumed an estimated 10500 mg of potassium each day, compared to a current US intake of 2500 mg. (9) Therefore, the sodium-potassium ratio of the modern diet is hugely mismatched to our genetically determined renal processing machinery. Additionally, the cardioprotective effects of a relatively high potassium intake have been hypothesized as a basis for low CVD rates in populations consuming primitive diets, where hypertension has been shown to affect only 1% of the population. (10)

Research suggests that increased intake of potassium, found in fruits and vegetables, may be more effective than, and possibly synergistic with, moderately restricting dietary NaCl in reducing not only the renal excretion of calcium, but also the level of blood pressure, the expression of hypertension, and the development of osteoporosis and kidney stones. (11) Therefore, a diet high in potassium-rich plant foods is crucial to preventing the negative outcomes typically associated with a high salt intake.

Magnesium has also been studied for its potential effects on blood pressure, which are poorly understood. Epidemiological studies have typically shown an inverse relationship between dietary magnesium intake and blood pressure, however data from clinical studies have been less convincing of magnesium’s role in treating hypertension. (12) Despite this conflicting evidence, some studies have shown that intracellular magnesium deficiency affects insulin resistance, alters vascular tone leading to hypertension, and induces pro-inflammatory changes and endothelial dysfunction, ultimately increasing the risk for CVD. (13) Therefore, a diet high in magnesium is likely beneficial for anyone at risk for hypertension or heart disease.

Calcium is another major mineral thought to play a role in blood pressure management. A high dietary intake of calcium, but not calcium supplementation, has been associated with both a decrease in blood pressure and the risk of developing hypertension. (14) In fact, calcium supplementation has been associated with a 30% increased risk of heart attack, and is potentially dangerous for those at risk for heart disease. (15) For those looking to protect themselves against hypertension and subsequent cardiovascular disease, a calcium-rich diet should suffice, with no supplementation required or recommended. (And of course, remember to keep vitamin K2 intake adequate as well!)

Take home message? Use your own judgment!

Ultimately, the amount of salt required for good health is based on individual needs, health status, and genetic predisposition to salt sensitivity. The evidence for salt restriction, even for those with cardiovascular or renal disease, is mixed and often times inconclusive. It’s important to remember that the data regarding sodium intake has been from populations typically eating a standard American diet, and it’s unknown whether salt intake would demonstrate any detrimental effects in a population eating a potassium, magnesium, and calcium rich whole foods Paleo diet. These are important points to consider when deciding how much salt to include in your own diet.

For my final article on salt, I will discuss the types of salt I recommend, and how much salt is ideal for most people.

Like what you’ve read? Sign up for FREE updates delivered to your inbox.

  • I hate spam too. Your email is safe with me.

Comments Join the Conversation

  1. Asia says

    What does one do who has had her lymph glands removed in the upper thigh area, for fear of cancer spreading, but years later now has terrible edema in that leg? salt restriction, and dandelion teas, some movement have been helpful, but not a complete answer. Is this another area where salt restriction is warranted, or is there another natural solution that would be better?

  2. Jean Weger says

    My husband takes chemo five days a month and also has many kidney stones. When getting chemo or blood transfusions he receives saline solution to flush iv lines. Sometimes he vomits at the time and sometimes 3 or 4 hours later. No food comes up but more like mucus. His urologist says not to eat salt but the oncologist says it is just a case of anixety and I don’t agree. He prescibed antivan but still had the same reaction. Could he be having high blood pressure. I worry he will have a heart attack when having these episodes. I would appreciate information. Thank you!

  3. says

    I was happy to see your last insight, that nearly every study out there is studying people who are living standard American lives. Given the massive interrelation of health factors, it’s wise to be cautious in reading studies. I feel that a more reliable way is to study aboriginal cultures who are known for health, because built-in, are the practices that create that, over generations.

    My concern with salt, is that I have no craving for it, and it kinda makes me want to gag, like if you were to drink seawater. Now much of the Ancestral Health community is jumping on the 3,700mg per day sodium bandwagon, it’s leaving me confused, giving my distaste for salt. Loren Cordain is still against salt, and Denise Minger admits she has no desire for it now. One wonders. Any thoughts?

  4. Darren says

    So, basically, i think what Chris is saying here, Westerners need to eat more good food, less junk food which would elevate HBP, then it’s not really necessary to restrict sodium intake, since good food would contain the necessary salt/potassium ratio we need…Am i right..?!?

  5. says

    Hiya Chris,
    Fantastic articles on salt, written in an understandable way, thank you. It was my firm belief that potassium deficiency and its out of balance consumption that has more to do with illness than just excessive salt input, this point is missed by so many alleged professionals in the nutritional and medical fields.
    Could I trouble you with a question please as my background is archaeology and sports not biology and there is one aspect of salt that confuses me about the apparent essential aspect of salt per se.
    Is it salt that is essential or sodium and chloride that are essential nutrients? This might sound dumb but it’s the electrical part I’m lost with – does dietary sodium from say kidney beans or beetroot get converted in the body to a positive ion, allowing for the electrylosis aspect within cells to perform?
    If so, where would a vegetarian get adequate chloride input to create the negative ions?
    Positive Harmonious Vibrations . . Karl . .

  6. says

    Hi Chris, I have a question about K2 and FCLO/BO from Green Pastures. We take a boatload of supplements and I’m looking at how I can get my vitamins from food sources. I’m a WAPF chapter leader living in KY, a wonderland of farms, so surely I can do this! I was just looking at the label and see that FCLO/BO has all the Omegas and A and D and K2? It doesn’t say K2 on it, but you had mentioned that in another post from ’09 about K2.

    My question is this: can I rely on this product to give me sufficient A and K2 and the Omegas? We take 10,000iu of D a day so maybe we would cut back to 5,000… I’m re-evaluating here and need some guidance. Thank you.

  7. says

    There’s at least one other serious condition that warrants salt reduction: Meniere’s disease, a condition where fluid levels in the inner ear get out of whack that produces severe vertigo attacks. A low sodium diet can do a lot to control symptoms (gluten free diets can also help some people). Personally, restricting my sodium keeps me mostly off vestibular suppressant meds, which have substantial side effects.

  8. says

    Really interesting article Chris. Its really refreshing to see healthcare practitioners recommending things based on what the literature states instead of blindly condemning things.

    Thanks for the good read,
    Dan

  9. says

    Hi Chris,

    Great article – exactly the information I need right now to help my Mum.

    She has very low sodium levels on testing (for a few years now) yet has had high BP in the past and a family history of heart disease. She also tests very low for aldosterone which I think explains the low sodium but the connection with high BP doesn’t yet make sense.

    In my mind, the high sodium = high BP equation is not the case for many people and can in fact, cause a lot of harm if one restricts their sodium too heavily.

    What are your thoughts on the accuracy of standard potassium blood tests as opposed to something like Red Blood Cell testing? I have had the RBC test for Potassium and was found to be deficient yet on regular testing it shows up fine. I’m trying to track down this testing in Australia for my Mum to have done, as I had it done in London.

    She’s under the care of an open minded holistic GP (MD) who has her on e-lyte electrolyte drink but I’m not sure she has enough sodium and potassium as she is very tired (I have seen many people benefit from increased sodium intake from sea salt when it comes to fatigue). I’ve printed this article and some of the referenced articles to take in to him to see what can be done.

    thanks again,
    Allison

  10. Vicki says

    What if you cannot eat any dairy, you have been lactose and casein intolerant since you were born? How do you get calcium w/o supplementation?? Lactaid is a joke. Had to have soy milk as a baby, ruined my thyroid. Almond milk makes stomach hurt, tried rice milk but found gluten intolerant so that eliminated cereal anyway, so hardly matters — except for calcium!

    I am a salt=sensitive equals edema person, so use unprocessed gray Celtic sea salt mixed half and half with Morton’s iodized Lite salt, for my adrenals, per hormone doc. Lasix was next for edema. Stripped minerals so bad, fainted in parking lot. I do take Potassium 2 x day, 20 mEq each, and Magnesium oxide 400 mg 2 x day. Can’t find Mag Bicylinate (sp).

    I don’t know how to get calcium w/o supplements. Any suggestions? I really miss yogurt.

    I am a 69 yo female post meno, w/ osteoporosis & fibro & hypothyroidism taking Natural Desiccated Thyroid compounded, not optimized yet; also dx with Adrenal Insufficiency (long-term severe stress), and Gut Dysbiosis “Leaky Gut” due to systemic and gut Candida which also prevents proper nutrition absorption; and gluten intolerance). Welcome all comments or help!

    • Helissa Penwell says

      Hi Vicki,
      I take calcium derived from plants (algae). New Chapter, the company that makes “Bone Strength Take Care”, claims that the body treats them like food. I’m hoping that means that they don’t have the problems that come with the usual calcium tablets. Nice small pills, too, that can be taken without food.

      Helissa

      • Jill Franz says

        The best source of calcium does not come from a supplement. Learn how to make a quality bone broth. All the minerals you need to maintain healthy bone can be found in a homemade broth. Drink broth straight, make soups or stews, gravies, use broth instead of water with rice, etc. It is easy to get it into your diet every day. Sally Fallon of the Weston Price Foundation has excellent recipes as do many other bloggers.

        • Cathryn says

          Jill, Vicki and Helissa,
          Been making sure I have bone broth every day, a couple big mugs and use the broth in the other ways you suggest, Jill, including cooking vegetables in it and drinking the broth after if I don’t want them soupy on my plate. Jaminet talked about bone broth on his Q&A page (Mar. 2) and said to continue boiling the bones down for a week and using the broth which continues to be mineral rich. Seems amazing that the bones could continue to exude so much good stuff. I also take all bones that have been roasted from chickens and lamb or beef roasts and save them in the freezer to make a batch of broth or add to my other bones. In the case of chicken, the bones get really soft and parts of them can actually be eaten. I heard Robb Wolf say he has always done this and they are a good source of calcium. I do this, too. It’s rather barbaric, I suppose, but who cares? I want to keep my bones strong.

  11. says

    This has been such a great series, thanks for putting it together. I too have been sharing your blog links with some of my patients because they get conflicting information from me vs. their physician, or worse yet, some think salt should not be used at all even though they have no apparent risk factors for hypertension or renal disease. I look forward to the next article.

Join the Conversation

Current ye@r *