When mice eat a lot of salt, adding a moderate amount of potassium lowers their blood pressure, showing that potassium's main benefit might be fighting high blood pressure caused by salt.

In mice eating normal salt, too much potassium (over 1.75% of their diet) makes their blood pressure go up during active hours, especially at high potassium levels like 5%, because of increased activity of certain kidney channels.

When mice eat a lot of salt, adding a moderate amount of potassium lowers their blood pressure by about 3.6 mmHg compared to eating the same high salt without extra potassium.

In mice eating normal salt, even though extra potassium slows down one salt-handling channel (NCC), it doesn't lower blood pressure because another channel (ENaC) starts pulling in more salt instead.

Long-term high potassium makes a kidney channel more active, and blocking that channel with a drug lowers blood pressure in mice.

Eating more potassium-rich foods doesn't change how much salt is passed in urine or body weight for people with high blood pressure over a year.