★★☆Single study — solid evidence, such as one good trial or a large observational dataset, but not replicated at the top tier.
A gram of table salt is 393 mg of sodium, not a gram
Table salt is sodium chloride, and sodium is 39 percent of it by weight. Potassium chloride, the usual salt substitute, is 52 percent potassium.
What the study found
A gram of table salt is 393 milligrams of sodium
The two figures on a nutrition label are not interchangeable. Table salt is sodium chloride, and sodium is 39 percent of it by weight, so a gram of salt delivers 393 milligrams of sodium. Potassium chloride, the usual salt substitute, is 52 percent potassium by the same arithmetic.
The caveat · Chemistry, not what a body does
A chemical identity record, not a study: it says what these compounds weigh and nothing about what they do in a body. Both percentages were calculated from the retrieved molecular weights rather than read off the record, so they carry that rounding.