So why is this important? Let's take an example. Salt and vinegar flavoured crisps. UK and EU food labelling regulations permit the declaration on the ingredients list of sodium or salt. It's up to the manufacturer. Now a lot of people know that the daily maximum recommended intake for an adult of salt is 6 gram. This has been the case for years. However, take a look at the ingredients list on a pack of Salt and vinegar crisps. Almost always the "salt" content will be declared. Why? Well it's because the sodium content figures huge and exceeds the daily maximum sodium intake because it not only includes the 39% sodium, but the monosodium glutamate added as a flavour enhancer and a huge quantity of sodium diacetate which gives the crisps the vinegary flavour.
Processed meat contains not only sodium chloride but sodium nitrite, sodium phosphates, sodium polyphosphates and other sodium salts so that when manufactures declare the salt content, they are not revealing the large, unhealthy additional sodium content derived from other sodium salts.
Corned beef is made my soaking beef brine and if that is not bad enough for those on a low sodium diet, it contains one of the highest permissible quantities of either sodium nitrate or sodium nitrite.
The information I've provided above can be verified by discussion with anyone with a modicum of knowledge of chemistry from "A"level. Just look up. Here's a reasonably simple link:
https://www.thoughtco.com/difference-between-sodium-and-salt-608498
Try this too:
https://www.fda.gov/Food/ResourcesForYou/Consumers/ucm315393.htm
Which foods contain high elemental sodium? You can include most processed meats (sodium nitrate/sodium nitrite), Chinese food (monosodium glutamate), vinegar flavoured foods or vinegar flavour granules (sodium diacetate/sodium acetate)
Everyone should be trying to reduce their Sodium intake. Sodium intake is not the same as Salt intake. In the UK, we should not be exceeding about 2.4g of sodium daily. This is the figure the government and food manufacturers should be emphasising rather than the salt figure.