low-sodium diet vs low-salt diet

low-sodium diet and low-salt diet both are nouns.

Word	Noun	Adjective	Verb	Adverb
low-sodium diet	Yes	No	No	No
low-salt diet	Yes	No	No	No

As nouns, low-sodium diet and low-salt diet are synonyms defined as:

low-sodium diet and low-salt diet: a diet that limits the intake of salt (sodium chloride); often used in treating hypertension or edema or certain other disorders

Other synonyms of low-sodium diet include salt-free diet.

low-sodium diet (noun)	low-salt diet (noun)
a diet that limits the intake of salt (sodium chloride); often used in treating hypertension or edema or certain other disorders	a diet that limits the intake of salt (sodium chloride); often used in treating hypertension or edema or certain other disorders