Could consuming soy interfere with thyroid medication? For people with adequate iodine, it doesn't seem to be a problem.
Will food and drink make a difference in how well you absorb your medication? Grapefruit, grapefruit juice and coffee can affect some drugs.
Salt substitutes with potassium chloride can lower blood pressure. But too much potassium can be deadly! Beware ACEis and ARB-type BP drugs!