The issue with this myth is not that it is completely baseless, but more that it may exaggerate what is usually a minor issue.
Studies have linked excessive salt intake with conditions such as high blood pressure and kidney damage, as well as an increased risk of cognitive decline. However, it’s important to note that drastically lowering slat intake has not shown significant health benefits in clinical trials.
Salt (sodium) is actually an essential mineral that your body needs - cutting it out entirely is not advisable, either. In fact, both very high and very low sodium intakes are associated with cardiovascular disease, so once again it is a case of moderation instead of elimination.
A big part of the issue of excessive salt intake is the source of the salt. ‘Western’ diets are filled with lots of salty, processed foods, which means that a lot of the people consuming a lot of salt are actually consuming lots of food that are generally ‘unhealthy’ (high calorie, hyper-palatable and low in nutritional value). Which makes it hard for us to separate the effects of a high salt intake with the effects of the overall diet.
Unless you have salt-sensitive hypertension, the evidence promoting a low sodium diet is less convincing than you might expect. Rather than majoring in the minors and focusing specifically on salt intake, most people would benefit from ensuring they follow a diet of mostly whole, unprocessed foods - the benefits we will gain from this will be far more noticeable than that of slashing our salt intake alone.