Scientists measured how fast tiny filters in the kidneys work in healthy people, and it's the first time they've directly checked this in living humans using special scans and tissue samples.

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.

Scientists counted the tiny filters in healthy Japanese people's kidneys and found there are about 685,000 on average, giving us the first clear picture of how many filters normal human kidneys have.