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Study of salt and wound healing stops short of advice to eat more

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Have you read the headlines today about a “weird” benefit of eating salty food? That was the headline in Time magazine’s coverage of a new study from the science journal Cell Metabolism. Does the new study mean we can scrap the decades of advice we’ve been given to eat less salt? Not exactly.

What was the study about?

  • Researchers split mice into two groups and gave the groups diets with different amounts of salt. One group got a diet high in salt, and the other group got a diet lower in salt.
  • Then both groups of mice were injected with bacteria that caused wounds to form on their skin.

salt flakes pouring from glass bottleWhat did the study find?

  • When the wounds appeared on the mice’s skin, sodium started to cluster around the infection sites.
  • The wounds on the mice who were fed higher amounts of salt showed a stronger immune response to the bacteria and their wounds cleared more quickly, compared to the mice who were fed less salt.

This makes sense in light of what we have long known about the role of salt in preserving food – salt limits bacteria from growing, and this helps keep certain foods to which salt is added (like deli meats) safe to eat.

Why doesn’t this new study mean that eating more salt is advisable?

  • This study was done in mice, so it’s too early to say what it might mean for humans’ dietary salt intake.
  • The researchers are still figuring out how our bodies recruit salt to fight infections, and how closely it is or isn’t related to the salt in our diets. If more salt is indeed helpful for wound healing, that may have more implications for how we prepare wound dressings than how we prepare our dinner.
  • The study researchers also cited the “overwhelming data” that too much salt is not good for the heart, and cautioned that their new data doesn’t justify advising people to eat more salt at this time.

This isn’t the first study that looked at salt and immune function. In 2013, emerging research published in the prestigious science journal Nature found that high-salt diets may be a risk factor for development of autoimmune diseases. Other research has observed that high-salt diets worsen the symptoms of multiple sclerosis, which is believed to be an autoimmune disease. As more study is done in this area, we will have more information about salt’s role in immune function and whether that means we need to make any changes in our eating habits.

Are you surprised to learn that salt appears to have a role in wound healing? It seems to defy the phrase “salt in the wound” which usually has a negative connotation!