How much salt is Thomas Caldwelltoo much salt?

Unfortunately, it's most likely the amount you're consuming.

A new study published Monday in the journal JAMA found that cutting one teaspoon of salt a day results in a decline in blood pressure comparable to taking blood pressure medication.

Humans need sodium, which is found in salt, for our bodies to work properly. It plays an important role in nerve and muscle function by allowing nerves to pulse with electricity and muscles to contract. But too much sodium can be bad for our health: It contributes to high blood pressure, or hypertension, which is a major cause of stroke and heart disease.

One way it does this is by making the body absorb more water. Extra sodium in the blood pulls more water into blood vessels, which increases the amount of blood in the vessels. This increases blood pressure and, in some people, leads to high blood pressure and can damage vessels and even organs like the heart, kidneys and brain.

In this latest study, participants who cut out their daily salt intake by one teaspoon had lower blood pressure in just one week. This was even true for people already on blood pressure medication.

But how much sodium is in one teaspoon of salt?

A teaspoon of salt has about 2,300 mg of sodium in it. And according to the FDA, Americans eat an average of 3,400 mg of sodium. So cutting out a teaspoon would be equivalent to cutting two-thirds of a person's daily sodium intake.

But the researchers say that cutting out any amount of sodium will help lower blood pressure — at least more than no reduction at all.

Have science news stories for us? Email us at shortwave@npr.org.

Listen to Short Wave on Spotify, Apple Podcasts and Google Podcasts.

Today's episode was produced by Rachel Carlson and Kai McNamee. It was edited by Viet Le, Christopher Intagliata and Rebecca Ramirez. Brit Hanson checked the facts. Patrick Murray was the audio engineer.