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One Way to Treat Asthma and Autoimmune Diseases with Diet

Cutting two teaspoons of salt’s worth of sodium from one’s daily diet can significantly improve lung function in asthmatics

In the 1960s and 1970s, a mystery was emerging. Why were childhood asthma rates between 2 to 5 percent in the developed world but as low as 0.007 percent in the developing world? For example, in the developing world, instead of 1 in 20 kids affected, or even 1 in 50 kids, it could be more like 1 in 10,000 kids—extremely rare. And, when kids moved from a low-risk area to a high-risk area, their risk went up. What was going on? Were they exposed to something new? Did they leave some protective factor behind?

As I discuss in my video How to Treat Asthma with a Low-Salt Diet, all the way back in 1938, scientists showed they could stop asthma attacks by lowering children’s sodium levels. That was done with a diuretic drug, but subsequent dietary experiments showed that diets high in salt seemed to increase asthmatic symptoms, while “lowering the salt decreased the asthmatic symptoms…” This body of evidence was apparently forgotten…until it was picked up again in the 1980s as a possible explanation for why Western countries had higher asthma rates.

Maybe it was the salt.

As you can see at 1:34 in my video, researchers graphed out childhood death from asthma versus family salt purchases, and it seemed more salt meant more death. Just because a family buys more salt doesn’t necessarily mean the kids are eating more, though. The way to find out how much salt someone is eating is to collect their urine over a 24-hour period and measure the amount of sodium, since how much salt we eat is pretty much how much salt we excrete. The way to test for asthma, called a bronchial challenge test, is to look for an exaggerated response to an inhaled chemical. And, indeed, there was a strong correlation between how their lungs reacted and how much sodium they were taking in. However, there are all sorts of food additives, like preservatives, that can trigger these so-called hypersensitivity reactions, so maybe high sodium intake was just a marker for high processed food intake. Maybe it wasn’t the salt at all.

Or maybe it was other components of the diet. For example, the reason sodium may be a risk factor for another inflammatory disease, rheumatoid arthritis, may be that sodium intake is just a marker for increased fish and other meat intake or decreased fruit and vegetable intake. We needed a study where researchers would take asthmatics, change the amount of salt in their diets, and see what happened—and that’s just what came next.

As you can see at 3:16 in my video, researchers doubled the salt intake of ten asthmatics, and lung sensitivity worsened in nine out of ten. There was no control group, though. Is it possible the subjects would have gotten worse anyway?

In a randomized, double-blind, placebo-controlled trial, researchers put everyone on a low-salt diet, but then gave half of the subjects sustained-release sodium pills to bring their salt intake back up to a more normal level and the other half a placebo. After five weeks, the groups switched regimes for another five weeks. That’s how you can randomize people to a true low-sodium diet without them even realizing it. Genius! So what happened? Asthmatics on the salt got worse. Their lung function got worse, their asthma symptoms got worse, and they had to take more puffs on their inhalers. This study compared asthmatics consuming about three teaspoons’ worth of salt a day to those consuming less than one, so they were effectively able to drop their sodium intake by two teaspoons’ worth of salt, as you can see at 4:04 in my video. If you do a more “pragmatic” trial and only effectively reduce people’s salt intake by a half a teaspoon a day, it doesn’t work.

Even if you are able to cut down your sodium intake enough to get a therapeutic effect, though, it should be considered an adjunct treatment. Do not stop your asthma medications without your doctor’s approval.

Millions suffer from asthma attacks triggered by exercise. Within five minutes of starting to exercise, people can get short of breath and start coughing and wheezing such that lung function significantly drops, as you can see at 0:19 in my video Sodium and Autoimmune Disease: Rubbing Salt in the Wound?. On a high-salt diet, however, the attack is even worse, whereas on a low-salt diet, there’s hardly a significant drop in function at all. To figure out why, researchers had the subjects cough up sputum from their lungs and found that those on the high-salt diet had triple the inflammatory cells and up to double the concentration of inflammatory mediators, as you can see at 0:43 in my video. But why? What does salt intake have to do with inflammation? We didn’t know…until now.

“The ‘Western diet,’ high in saturated fatty acids and salt, has long been postulated as one potential…cause for the increasing incidence of autoimmune diseases in developed countries…” The rapidly increasing incidence of autoimmune diseases may be due to an overactivation of immune cells called T helper 17 (Th17) cells. “The development of…multiple sclerosis, psoriasis, type I diabetes, Sjögren’s syndrome, asthma, and rheumatoid arthritis are all shown to involve Th17-driven inflammation,” and one trigger for the activation of those Th17 cells may be elevated levels of salt in our bloodstream. “The sodium content of processed foods and ‘fast foods’…can be more than 100 times higher in comparison to similar homemade meals.”

And, sodium chloride—salt—appears to drive autoimmune disease by the induction of these disease-causing Th17 cells. It turns out there is a salt-sensing enzyme responsible for triggering the formation of these Th17 cells, as you can see at 2:07 in my video.

Organ damage caused by high-salt diets may also activate another type of inflammatory immune cell. A high-salt diet can overwork the kidneys, starving them of oxygen and triggering inflammation, as you can see at 2:17 in my video. The more salt researchers gave people, the more activation of inflammatory monocyte cells, associated with high-salt intake induced kidney oxygen deficiency. But that study only lasted two weeks. What happens over the long term?

One of the difficulties in doing sodium experiments is that it’s hard to get free-living folks to maintain a specific salt intake. You can do so-called metabolic ward studies, where people are essentially locked in a hospital ward for a few days and their food intake is controlled, but you can’t do that long term—unless you can lock people in a space capsule. Mars520 was a 520-day space flight simulation to see how people might do on the way to Mars and back. As you can see at 3:17 in my video, the researchers found that those on a high-salt diet “displayed a markedly higher number of monocytes,” which are a type of immune cell you often see increased in settings of chronic inflammation and autoimmune disorders. This may “reveal one of the consequences of excess salt consumption in our everyday lives,” since that so-called high-salt intake may actually just be the average-salt intake. Furthermore, there was an increase in the levels of pro-inflammatory mediators and a decrease in the level of anti-inflammatory mediators, suggesting that a “high-salt diet had a potential to bring about an excessive immune response,” which may damage the immune balance, “resulting in either difficulties on getting rid of inflammation or even an increased risk of autoimmune disease.”

What if you already have an autoimmune disease? In the study titled “Sodium intake is associated with increased disease activity in multiple sclerosis,” researchers followed MS patients for a few years and found that those patients eating more salt had three to four times the exacerbation rate, were three times more likely to develop new MS lesions in their brains, and, on average, had 8 more lesions in their brain—14 lesions compared to 6 in the low-salt group. The next step is to try treating patients with salt reduction to see if they get better. But, since reducing our salt intake is a healthy thing to do anyway, I don’t see why we have to wait.


What else can we do for asthma? See:

Have you heard that salt reduction was controversial? That’s what the processed food industry wants you to think. Check out the science in:

What are some of the most powerful dietary interventions we have for autoimmune disease? See, for example:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Discuss

Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.


31 responses to “One Way to Treat Asthma and Autoimmune Diseases with Diet

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  1. I get exercise-induced asthma, and I don’t use salt. I do pay attention to the salt in the very few manufactured products that I buy ie bread, soup base, soy milk, canned tomatoes and beans. Doing without salt can cause problems though with getting enough iodine, and with exercising / electrolyte imbalance.

    1. Barb,

      For iodine, and other reasons (I really like it), we’ve been adding a small bit of dried wakame seaweed to miso soup, which we eat a few times a week. Miso soup itself has quite a bit of salt, so we limit our consumption of it as well. I’ve thought about adding some rehydrated wakame to salads, but haven’t tried it yet. Though I do really enjoy seaweed salad.

      1. Thanks Dr J but I don’t use miso or other soy products except the milk. I will have to see what’s out there . Maybe chipping a bit off a kelp tablet would be enough. I also have to check what is safe to take if a person has hypothyroid.

    2. When my son was about 10 years old we took him to the emergency room because after his soccer game he had trouble breathing. They gave him steroids through an inhaler and deemed him “asthmatic” and gave me a prescription for steroids and an inhaler and said that he would be using this device for life. I did my own research and found that the lungs will constrict in order to conserve moisture/water. Knowing my son did not drink enough water I put him on a 1 oz/2 lb body weight water per day. I explained to him what I read and told him he had a choice … he chose water. He’s now 24 years-old and has never had another incident of “asthma”. I know his case is not unusual … our society is chronically dehydrated. Simply drinking 1oz per 2 lbs of body weight per day could change your life!

      1. Darris, thanks for your comment! Oddly, some of my worst exercise asthma occurs in water, swimming. I will definitly being doing my own experiments this summer though since I am trying to keep inhaler use to a minimum. Thanks again.

  2. Hi,
    Thank you for this. Is there a risk of long-term low-sodium intake? I did some blood test and I was given a low potasium result. yet I eat lots of dried fruits, bananas, and a healthy diet. I was told that this would be because of a low-salt intake (I do not add salt and do not eat processed foods).
    Is this true?

      1. I found a list of potential things.

        Here is their list of common causes

        Low Folic Acid
        Low Magnesium
        Too much water intake
        Too much exercise
        Not enough food or enough variety in food intake
        Too many Ketones in blood / ketoacidosis
        Antibiotics / Medicines
        Diarrhea / Vomiting / Bowel problems /Crohn’s, Colitis
        Absorption issues Any type of disease that affects the lining of the stomach may cause issues with the absorption of nutrients.
        Underlying heart conditions
        Long term alcohol use because of problems with pancreas, liver

        The following syndromes also were listed.
        Bartter syndrome
        Cushing’s syndrome.
        Fanconi syndrome
        Liddle Syndrome
        Gitelman syndrome

        Bone density issues are mentioned as associated – I am confused whether they meant that it was causal but I put it as something to look at.

        Being too low salt was not on the list at all in any of the ones I looked at.

        But I am not a medical person. I am just reading lists of causes of low potassium and what I noticed is that being too low in sodium is not on any list.

    1. A “healthy diet” means different things to different people. If you paste a food log of few days we might be able to help.

    2. Maybe some miso paste would be good for you. Dr. G. cited research which indicated that miso paste does not cause problems that other salt sources cause. He still advises that we not overeat miso, so maybe a one teaspoon serving every day is permissible.

  3. I was low salt for years before I went WFPB no SOS because I lived with my brother who was a kidney transplant patient on a very low salt diet. My sodium has been low in blood tests for years, frequently falling out of the “normal” range. The only time I was advised to eat some salt was when my blood pressure dropped to 80/50 and freaked out my nephrologist. He told me to eat a can of Campbell’s soup as the prescription for getting a big bump in sodium! I have no problem with electrolytes in spite of exercising for an hour a day on an elliptical.

    1. Barbie,

      My brother once suffered from excessively low sodium, after he switched to whole plant foods eating, and avoiding added salt, sugar, and oil. He was advised to put a pinch of salt in his morning oatmeal, which solved his problem. That seems a much healthier solution than eating a can of Campbell’s soup.

      And his diet solved a number of issues he had, including excess weight, T2 diabetes, high BP, high cholesterol, GERD, etc. All resolved, except for BP, which is now almost completely under control.

  4. Another great blog and I love the videos every day also. One small suggestion, too many “as you can see at 2:07 in my video.” Two or three of these is fine. More than that and it starts to look like a computer software program wrote the article. LOL :)

  5. Fascinating. I had always thought that the issue was largely due to over- processed salt and that the sea salt was good for you.

    Dry Salt Therapy ( inhaling super fine microns) is great at reducing inflammation and clearing congestion.
    And there are clinical studies working with asthmatics.

    Have you investigated it?

    1. The issue with salt is its sodium content. There’s just as much sodium in sea salt as table salt. Ditto for Himalayan salt and all the other overpriced salts. The alleged benefits of these salts are just worthless marketing claims.

      Consuming large amounts of sea salt is as bad for your health as it is for your wealth..
      https://www.dole.com/en/Articles/sea-salt-scam

  6. I love salty food but discovered it triggers my dermographism, an autoimmune skin condition with no known cure. I should add that I have the skin condition despite eating a whole food plant based diet, so I’m not consuming huge amounts of salt hidden in processed foods.

    I’ve since replaced salt with miso paste when cooking, which doesn’t seem to trigger it. If I have soy sauce or end up having to eat something on the go, it’s triggered again because of the salt content. Unfortunately, I haven’t been able to reverse the condition completely but can now tolerate it without medication. Hopefully, in time, it will improve further.

    While searching online for a connection between salt and dermographism (which I didn’t find), I found a study where researchers had inadvertently found an accumulation of salt under the skin of people with eczema (or something to that effect). I’m sure, in time, we’ll discover many conditions are triggered by salt.

  7. Thank you Deb, Barb and others for your replies. Certainly something to keep an eye on and lots of ideas to follow up through. Thank you!

  8. I don’t intentionally add salt to anything. However I have found that to stop cramping I take a small pinch of salt and it stops it instantly. Any idea why?

  9. This is very intersting, and such a no-brainer to implement now that we know.

    Just thinking out loud…

    The studies mentioned are about dietary sodium, but what about intravenous? I wonder how the use of 0.9%NaCl or Lactated Ringers affects the immune response, especially in Covid patients pre- and during ventilation? I can see where these ubiquitous solutions can be both advantageous and now, potentially detrimental? I mean, I understand the immune system is complex, but for already immunocompromised patients, this could be a factor.

  10. Adam,

    Interesting you should ask. I thought looking through the literature you’d find these publications of interest, both in terms of inflammatory and immune function;

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5802674/ and speaking of a trauma situation see this article: https://www.jems.com/2018/03/14/three-reasons-not-to-use-saline-or-crystalloids-in-trauma/

    And then consider, “In addition, studies suggest that lactated Ringer’s solution may have significant effects on immune response by modulating leukocyte function” (https://www.sciencedirect.com/topics/nursing-and-health-professions/ringer-lactate-solution)

    This should give one some considerations when using IV fluids.

    Dr. Alan Kadish moderator for Dr. Greger http://www.Centerofhealth.com

  11. My son was diagnosed as “possibly” having an autoimmune disease called Behçet’s disease. He had a flair up of Uveitis and is on prednisone (60mg) to lower the inflammation. He asked if diet could help control the symptoms rather than the medication. They said no diet does not have an affect. He has stomach issues, cancer sores and joint pain that has gone on for years. He is 29 years old and has not had a balanced diet. He now has switched to a plant based diet. Added vitamin D and B-12 and is eating frequently. Any idea about research regarding plant based diets and autoimmune disease when relating to treating uveitis. I feel using diet to treat inflammation would have an impact on his whole system. Any thoughts?

  12. Hi, Raquel! I am so sorry your son has been dealing with autoimmune issues. You can find more information about uveitis here: https://nutritionfacts.org/2020/03/19/benefits-of-turmeric-curcumin-for-uveitis-and-eye-cancer/ and here: https://nutritionfacts.org/video/benefits-of-turmeric-curcumin-for-inflammatory-orbital-pseudotumor/ Although Behçet’s disease has not specifically been covered here on NutritionFacts, research is revealing a common cause for autoimmune diseases; our gut flora. A healthy gut flora depends on the diversity of whole plant foods in the diet. You can find everything on this site related to autoimmune diseases here: https://nutritionfacts.org/topics/autoimmune-diseases/ I hope that helps!

    1. Thank you so much. I saw a bunch on autoimmune but not this one. I really appreciate the quick response. Trying to find someone in the Washington area that is educated in a plant based lifestyle and nutrition has been challenging. Every little bit of info helps. So grateful for this site.

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