Other Jim Fixx morals:
1) If you lead an unhealthy life, and later decide to reverse course, it may be too late.
2) So train your children well and get started now.
3) And when you have chest pain when you run, for Dawkin's sake, don't keep going out for runs until you die of a heart attack and end up the source of morals on the Dojo Roundtable. Fixx ignored warning signs.
K Factor:
I'm not aware of any major evidence that the ratio of K to Na is important beyond the major point that you want to minimize your sodium intake to about where it hurts. Americans eat 4, 6 and more grams of Na a day; the advice? 2 grams. To get there, you need to exclude almost anything that adds salt to nature's products, which means the salt shaker is gone, salt in recipes is gone, processed and fast and restaurant and most Asian food is mostly gone. America thinks salt is flavor; it's not, it's saltiness, but to improve "flavor" its crammed into everything. Learn to use other seasonings. I'll try to get the meat from this article for the forum later:
JAMA -- The Urgent Need to Reduce Sodium Consumption, September 26 ...
The Urgent Need to Reduce Sodium Consumption. Stephen Havas, MD, MPH, MS; Barry D. Dickinson, phd; Modena Wilson, MD, MPH. JAMA. 2007;298:1439-1441.
As for potassium, sure, it's helpful. A high K low Na diet does correlate with lower BP. The effect on individuals is small, however. It's usually just a few points which means that all my patients who come in at 160/94 can get to 156/92 with diet! Awesome, right! High K foods also include orange juice, potatoes, avocado, prunes, figs, and milk:
http://www.essortment.com/all/potassiumfoodh_rkyn.htm
Know your specific situation; people with kidney disease can get into serious trouble with K, people on diuretics may need more; people on certain medications like digoxin, sotalol, amiodarone, and other heart medicines are more sensitive to electrolyte disturbances. Eating a high K diet by favoring fruits and milk won't hurt you if you have relatively normal health. Dietary K has a minimal effect on serum potassium because it is absorbed gradually, and is easily buffered in cells (where almost all the K is found) until excess K can be peed out. It's K in serum that affects the heart's electrical system, so when Bill (or Texas and California) kill animals and inmates with K, they give it IV all at once. During my residency, a nurse misprogrammed an IV pump and executed a healthy patient with a dose of K equivalent to about 4-5 bananas--the patient was dead 30-40 minutes but came back without brain damage due to immediate recognition and care.
Thus: no IV bananas.
As for specific effects on preventing and treating hypertension, try this:
http://www.cmaj.ca/cgi/content/abstract/160/9/s35
Going overboard and especially Calcium and Mag aren't going to help.