Caffeine is not for AF!
All the sources I've read say it's the palmitic acid that's the active ingredient. Search around for palmitic acid and glutathione-S-transferase together.
http://www.google.com/search?q="palmitic%20acid"%20"glutathione-S-transferase"
Puts SAWilson's page into question. Sellers of coffee might better be treated as biased parties.
For absorption, note that the hepatic portal system reaches the sigmoid colon and even as far as the rectum.
I have yet to see a single AF sufferer who has this level of knowledge (extent of the hepatic portal system and which part of coffee is the active ingredient) recommend coffee enemas.
Some folks say the caffeine goes to the liver first and is metabolized before it can get into your blood stream. What they don't say is that even if this is the case, when caffeine is metabolized 84% of that caffeine turned into paraxanthine.
http://en.wikipedia.org/wiki/Caffeine#Metabolism_and_half-life
And that "Like caffeine, paraxanthine is a psychoactive central nervous system (CNS) stimulant. It possesses a potency roughly equal to that of caffeine and is likely involved in the mediation of the effects of caffeine itself."
http://en.wikipedia.org/wiki/Paraxanthine
I haven't seen anything that legitimizes putting caffeine anywhere in your body for AF therapy.
AF folks who are
coffee enema true believers would do well to get a good understanding. If palmitic acid is supposed to be the active ingredient ... maybe you can get that from other sources and not have to freak out your CNS with a stimulant? I bet you could get the same effect or maybe even much stronger effect than a
coffee enema with some cream, hold the coffee.