Salty food is very bad for babies and small children. It harms them in many ways. Two new newspaper articles this week draw attention to the harmful effects of salty food on children. In the Telegraph we read that cow's milk is too salty for babies and in the Independent we learn of a study finding that parents are feeding babies too much salty food, e.g. bread and baked beans. Babies and small children need to be protected from salt, not just because of harm in the present - higher blood pressure, serious damage to their immature kidneys, raised risk of heart disease and stroke, type 2 diabetes and all the other degenerative health conditions - but because by developing a taste for salt, or even an addiction to salt, these health difficulties will multiply throughout their (very likely shortened) lives. Inappropriately high salt intake is also a major cause of child obesity. And see Sodium in Foods.
If you harm a baby by feeding it salty food, the harm is permanent; you cannot undo that harm later.