Sodium levels in salted cooking water

[lovebenton0]

Back again, Mr McGee, with a basic concern.

Sodium levels can be a valid concern for some people, as it is for myself, beyond the obvious consideration of taste. When cooking potatoes and pasta for instance, in salted cooking water to be drained, is there a formula for determining the absorption of salt in food?

As in X amount of salt added to X amount of water with X weight of food?

[Harold McGee]

I don’t think there’s any way to generalize about salt uptake into foods—it depends a lot on the food, exposure time, and other factors. Potatoes will absorb relatively little salt, and mainly at the surface, because it’s already mostly water; pasta will take up more because it’ll nearly double its weight with absorbed water that penetrates all the way to the center.