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:

The Benefits of Slow Breathing

There are all manner of purported hiccup “cures,” which include everything from chewing on a lemon, inhaling pepper, or, our dog’s favorite, eating a spoonful of peanut butter. In my video How to Strengthen the Mind-Body Connection, I talk about the technique I’m excited to try the next time I get hiccups: “supra-supramaximal inspiration,” where you take a very deep breath, hold for ten seconds, then, without exhaling, breathe in even more and hold for another five seconds, and then take one final, tiny breath in and hold for five last seconds to achieve “an immediate and permanent termination to hiccups…”

When I was a kid, I taught myself to control my own hiccups using slow-paced breathing, and, as an adult, was so excited to see there was finally a case report written up on it.

There’s a nerve—the vagus nerve—that goes directly from our brain, to our chest, and to our stomach, connecting our brain back and forth to our heart and our gut, and even to our immune system. The vagus nerve is like the “‘hard-wired’ connection” that allows our brain to turn down inflammation within our body. When you hear about the mind-body connection, that’s what the vagus nerve is and does. “There has been increasing interest in treating a wide range of disorders with implanted pacemaker-like devices for stimulating the vagal afferent [vagus nerve] pathways,” but certain Eastern traditions like Yoga, QiGong, and Zen figured a way to do it without having electrodes implanted into your body.  

“A healthy heart is not a metronome,” as a study titled exactly that explains. “Your heart rate goes up and down with your breathing. When you breathe in, your heart rate tends to go up. When you breathe out, your heart rate tends to go down.” Test this out on yourself right now by feeling your pulse change as you breathe in and out.

Isn’t that remarkable?

That heart-rate variability is a measure of vagal tone—the activity of your vagus nerve. Next time you’re bored, try to make your heart rate speed up and slow down as much as possible within each breath. This can be done because there’s an entirely other oscillating cycle going on at the same time, as you can see at 2:08 in my video, which is the speeding up and then slowing down of your heart rate, based on moment-to-moment changes in your blood pressure. And, as any physics student can tell you, “all oscillating feedback systems with a constant delay have the characteristic of resonance,” meaning you can boost the amplitude if you get the cycles in sync. It’s like pushing your kid on a swing: If you get the timing just right, you can boost them higher and higher. Similarly, if you breathe in and out at just the right frequency, you can force the cycles in sync and boost your heart rate variability, as you can see at 2:36 in my video.

And what’s the benefit again? According to the neurophysiologic model postulation it allows us to affect the function of our autonomic nervous system via vagal afferents to brainstem nuclei like the locus coeruleus, activating hypothalamic vigilance areas.

Huh?

In other words, it’s not just about curing hiccups. Practicing slow breathing a few minutes a day may have lasting beneficial effects on a number of medical and emotional disorders, including asthma, irritable bowel syndrome, fibromyalgia, and depression. In the United States, we’ve also put it to use to improve batting performance in baseball.

To date, most studies have lacked proper controls and have used fancy biofeedback machines to determine each person’s resonant frequency, but, for most people, it comes out to be about five and a half breaths per minute, which is a full breath in and out about every 11 seconds. You can see the graph at 3:34 in my video. When musicians were randomized into slow-breathing groups with or without biofeedback, slow breathing helped regardless. It’s the same with high blood pressure. As you can see at 3:52 in my video, you can use this technique to significantly drop your blood pressure within minutes. The hope is if you practice this a few minutes every day, you can have long-lasting effects the rest of the day breathing normally.

Practice what exactly? Slow breathing—taking five or six breaths per minute, split equally between breathing in and breathing out. So, that’s five seconds in, then five seconds out, all the while breathing “shallowly and naturally.” You don’t want to hyperventilate, so just take natural, shallow breaths, but be sure to simply breathe really slowly. Try it the next time you get hiccups. Works for me every time!


For more tips, watch my video on How to Stop Hiccups.

And, because slowing down our pulse in general may also have beneficial effects, I encourage you to check out:

Every time I’m amazed by ancient wisdom, I have to remind myself of the video I did on toxic heavy metals—Get the Lead Out. So, though traditional healing methods may offer a plethora of insights, they still need to be put to the test.

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:

Vitamin D Put to the Test for Crohn’s Disease

Inflammatory bowel disease (IBD), “a chronic inflammatory condition of the intestine that causes abdominal pain, diarrhea, and weight loss,” includes Crohn’s disease and ulcerative colitis. When we compare identical twins, even though they have the same genes, most of the time, if one twin has IBD, the other does not. In that case, there must be some important, non-genetic trigger factors. What might they be?

Studies like the ones I discuss in my video Vitamin D for Inflammatory Bowel Disease offer a clue. Why do those living in the southern United States have lower IBD rates than those living in the north? Maybe it’s because Southerners get more sun, which means more vitamin D and which may also mean less inflammation.

So, do people with Crohn’s and ulcerative colitis who have low vitamin D levels have worse disease? Apparently so. Not only is there an increased risk of surgery and hospitalization, but those who normalize their vitamin D levels appear to reduce their risk of relapse. However, instead of better vitamin D levels leading to better Crohn’s, maybe better control of Crohn’s led to better vitamin D. Indeed, perhaps they felt so good, they went outside more, “increasing physical activity and outdoor sun exposure.” We can’t tell if it’s cause and effect unless we put it to the test.

The first pilot study tried 1,000 units of vitamin D a day and saw no change in the Crohn’s disease activity index. At six weeks, however, there may have been a slight increase in IBD quality of life scores, but even that disappeared by year’s end, so the results were pretty disappointing overall. Perhaps the researchers didn’t use enough vitamin D? How about 1,200 IU a day? At that level, the relapse rate appeared to be cut in half, as you can see at 1:45 in my video, though there were too few people in the study to reach statistical significance. What happens with 2,000 IU of vitamin D a day? Gut leakiness (so-called intestinal permeability) continued to worsen in the placebo group, but appeared to stabilize in the vitamin D group, though only those who reached blood levels over 75 nanomoles per liter appeared to have a significant drop in inflammation. And, indeed, if Crohn’s patients are started on 1,000 IU of vitamin D per day and then the dose is ramped up until a target blood level is reached, it’s possible to get a significant boost in quality of life accompanying a significant drop in disease activity, as you can see at 2:19 in my video. Disease scores under 150 are considered remission, so “the majority of patients achieved remission” with improvements in disease activity in all but one person in the study. This suggests that Crohn’s patients may want to take 5,000 IU of vitamin D a day, but that’s nearly ten times the Recommended Daily Allowance. Why so much? Because that’s what it may take to get vitamin D levels that are normal for our species—that is, the kind of levels one might get running around half naked in Africa, as we did for millions of years.


For more on the role diet can play in preventing and treating inflammatory bowel diseases, see:

Interested in learning what else healthy vitamin D levels can do for you and your family? Check out:

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: