A study found that eating more salt didn't really change how well the tiny filters in your kidneys work in healthy Japanese adults, even though people who ate more protein also tended to eat more salt.

Eating more protein is linked to how well your kidneys filter blood, even when considering other health factors like weight and blood pressure.

Eating more protein, adjusted for your ideal weight, is linked to better kidney filtering in healthy Japanese adults, even when other health factors are considered.

When healthy young men eat a lot more salt, their kidneys filter blood faster — up to 40% more — even though their blood pressure only goes up a tiny bit.

When healthy young men eat a lot more salt for a week, their kidneys filter blood faster — not because their blood pressure goes up, but because their kidneys just work harder to get rid of the extra salt.

If you measure salt intake in healthy adults using multiple urine tests over many years instead of just one, you might get a very different picture of how much salt people eat — and that can change what we think about how salt affects heart and kidney health over time.