When Blood Potassium is too High I recommend that you design your diet to receive large amounts of potassium, at least up to the as grown amounts in vegetables. As already mentioned, I believe that this strategy will tend to protect you against future excess potassium shock as well as short term losses. However, you should keep in mind that too much potassium can have some undesirable side effects. It is fairly well accepted that potassium can create a situation in which muscle spasms or cramps are more likely. While the relation is not established beyond any doubt, the statistical evidence is reasonably convincing .
Vitamin D is really a hormone which depends on ultra violet light in sunshine for synthesis.
However, people who work indoors, or wear a lot of clothing, and almost everyone in winter time in frigid areas would have to treat it as if it were a vitamin. Since it is present only sporadically in foods, such people would have to supplement to get realistic amounts. Liver, sardines, and irradiated milk are the only food sources that I know of, and even milk is usually inadequate alone. Vitamin D is especially important for people who must be inside away from sunlight. He maintains that 200 IU merely prevents osteoporosis after a fashion.