3 Reasons Salt Is Bad: Arteries, Asthma, Autoimmune Diseases

salt is bad
salt is bad

This past week, we’ve been dipping our toes into an ocean of information on ways in which salt is bad for our health. Sitting on my nightstand are unread books with “Salt” in their titles, so I’ll definitely be revisiting the topic in the New Year.

For now, however, we’ll end this brackish week with more concerns about excessive sodium intake.

Hypertension, of course, is the number one health threat associated with a high-sodium diet. But it’s just one in a long list of reasons salt is bad! They’ll require two posts to cover, so let’s get started!

Salt Is Bad for Arterial Function

In this video, Dr. Greger reviews multiple studies showing salt is bad for our arterial function.

One of them, Dietary sodium loading impairs microvascular function independent of blood pressure in humans, shows how it can stiffen arteries without affecting blood pressure. 

 And another, Dietary sodium restriction reverses vascular endothelial dysfunction in middle-aged/older adults with moderately elevated systolic blood pressure, concluded that a low-sodium diet can reverse arterial stiffening.

In other words, reducing salt intake will make your blood vessels’ inner lining (endothelium) suppler. Your blood will flow more easily through your body, even if your blood pressure is only slightly elevated.

Salt Is Bad for Asthmatics

Research linking asthma and high-sodium diets dates all the way back to 1938, when studies first revealed that lowering salt intake could halt asthma attacks. In fact, raising or lowering the salt intake triggered or reduced not just the attacks, but other asthmatic symptoms.

Scientific data collected during the 1960s and 1970s showed that roughly 3 percent of children in developed countries were asthmatics. In less developed ones, however, the rate was 1/300th of that (1 in 10,000)!

 Could Western foods’ higher salt content account for the difference?

Yes! Researchers actually mapped out the relationship between childhood asthma mortality and the amount of table salt purchased in a given country. Their conclusion?

More salt equaled more asthma. 

The 1980s brought more studies affirming the high-sodium diet/asthma connection. And, if there were still any doubt, the 1990s brought : 

  • randomized
  • double-blind
  • placebo-controlled


crossover research revealing exactly the same thing.

According to Dr. Greger’s review , it found that “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.” 

Salt Is Bad for Autoimmune Disease/Inflammation 

When I was growing up, only one of my family members suffered from asthma. Sometimes when we’d play or wrestle around, he’d suddenly have trouble breathing. We got very good at helping him find his inhaler!

He still played some sports, but always needed to have his inhaler handy. So naturally, a study looking at at causes for exercise-induced asthma really caught my eye.

Its participants on high-salt diets experienced higher inflammation. They had double the inflammatory mediators and triple the inflammatory cells of the low-salt group.

What led to their inflammation?

Dr. Greger reviews multiple studies pointing to the “overactivation of immune cells.” And inflammation is also linked to: 

  • Multiple sclerosis 
  • Psoriasis 
  • Type 1 diabetes
  • Sjögren’s syndrome
  • Rheumatoid arthritis


As he reflects, “…[S]odium chloride, salt, appears to drive autoimmune disease.”

The same video discusses German, Russian and American research into a high-salt diet’s long-term effects. it tracked members of the Mars520 project, who spent 520 days in a space capsule simulating a round-trip to Mars.

The conclusion?

…[A] high-salt had a potential to bring about [an] excessive immune response,” which resulted in “difficulties [in] getting rid of inflammation or even an increased risk of autoimmune diseases.”

For those already suffering from autoimmune diseases, the news is equally problematic. This 2014 study tracked 70 MS patients’ sodium intake over two years.

It found that compared to the low-salt group, the high-salt group had an average of eight more existing brain lesions. And they were three times more likely to develop new ones.

Why The Salt/MS Connection Strikes Home

Last night, my Dad’s best friend Mike D. died. I first met him as a teenager, when he was already confined to a wheelchair with MS. One of the most positive people I’ve ever met, he never complained.

But his suffering was far beyond what I can comprehend. He’s been in our minds and hearts all day, and I’ve thought of him often while writing this post.

He cheered me on as I started my restaurant. And as I’ve studied and written about health and wellness in 2020, his encouragement never wavered.

Although Mike will never read these words, I’m sure he would have something positive to say about them. Because he always found the best in every situation, even when nobody else could.

Having Mike in my life taught me just how devastating autoimmune diseases are. So any health tips which can relieve someone suffering from one can profoundly impact their ability to enjoy life.

Even life in a wheelchair.

I hope that more people begin to take seriously diet’s influence on health and well-being. The research affirming that salt is bad is out there! 

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