Salt substitutes for cancer patients?

My grandma was diagnosed with lung cancer, and will be going through chemotherapy along with a great nutrition plan from "Beating Cancer with Nutrition". However, her holistic doctor recommended to try an alkaline diet (basic foods, non-acidic). So she needs to have low salt, but a lot of recipes call for salt. Anyways, my question is, is there a substitute for salt that will be good for a cancer patient?