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.

Measuring salt intake just once might make us think it's more or less harmful than it really is—using multiple measurements over time shows the risk could be very different, by as much as 85%.

People aged 30 to 54 who eat more salt over several years are 12% more likely to die from any cause for every extra 1,000 mg of salt per day—and eating very little salt doesn’t seem to help them live longer.

If you eat a lot of salt—like 18 grams a day for 10 days—your body will flush out more salt in your urine and also have a bit more salt in your blood, which proves you actually ate the salty food they gave you.

If you eat a lot of salt—like 18 grams a day for 10 days—your body will pee out more salt and your blood will have a bit more salt too, which proves your body is responding as expected to the extra salt.

Eating more salt is linked to a higher risk of heart disease, and this seems to be true whether scientists measure salt intake from what people remember eating or from their urine tests.