bioavailability?

[Dr. Fagbot Q. MacGillicuddy, PhD]

i did searches here for "bioavailability" and "bioabsorption" and didn't turn anything up, so i thought i'd start a topic addressing this. i apologize in advance if this was beat to death six months ago or whatever.

i'm interested in scientific, evidence-based research and information on vitamin-pill bioavailability. i'll probably keep taking vitamins regardless of information presented, just for placebo effect and also because they make my pee look like a pretty rainbow, but some practical info on their efficacy would be nice too.

what i'd really like to know is if there are reliable reference materials available, online or elsewhere, so i can go find the information i need myself, judge the source's veracity, etc.

i also wouldn't mind hearing from gajuscaesar, dochter or others with a biology/medical/science background on this subject. it'd be cool if folks along these lines choose to weigh in with specific, researched and tested information about which vitamins are fat or water soluble, and how you can tell. or if different types of fats matter. or if different vitamins or substances (like caffeine) impede bioavailability.

i would prefer not to hear from hippies, people repeating something some dude at a party told them, vitamin salesmen, mystics, reiki practitioners, hannibal, chiropractors, wizards, people who can't even describe the very basic concept underlying the scientific process, mages, gelflings or any members of the short-bus brigade cluttering up the board. however, should you choose to use this opportunity to **** forth your fruitloop ideas about, say, megadosages curing cancer or perhaps some sort of resonance theory, i will happily mock and belittle you.

i also welcome any attempts to derail the thread with stupid jokes, preferably involving boobies, weiners or doo-doo.

thanks in advance.

[Deadpan Scientist]

Fat Soluble vitamins: A D E K
The rest are water soluble.

Everyhing you ever wanted to know about anything scientific is at http://www.pubmed.gov

[Deadpan Scientist]

As to how you would tell that... You would probably have a mixture of water and oil, drop some of the vitamin in, mix things up, then take a gas chromatograph to measure the concentration on both sides, and then from that calculate the solubiliy constant. The ones that perfer oil will be called fat soluble, and the ones that prefer water will be called water soluble....
(note: this is just one way that it could be done, there are others)

[Dr. Fagbot Q. MacGillicuddy, PhD]

thanks very much. the site is extremely helpful.

i'm not sure what i was thinking when i wrote "...and how you can tell." but thanks for the answer nonetheless.

any guidance on how much fat is necessary to process fat-soluble vitamins in pill form? does it depend on the specific vitamin? i'm looking through the papers on that site now, but i'm stupid and it's slow going, especially for general info.

[Xango]

It's a complex subject and it's far enough away from my field of study that I'll mostly leave it to the others.

I can tell you one useful thing, though. Vitamin C is bioactive as ascorbate anion, not as ascorbic acid. Therefore if you are taking ascorbic acid, you don't see benefit from it until it moves down into the (duodenum?) where gall secretions raise the pH. Taking buffered vitamin C, like E-mergen-C, will let the stuff soak in through the stomach wall, which is nice if you're covered in bruises and sweat and just want some sweet anti-oxidation ASAP. Also makes your vitamin c a source for magnesium, potassium, and calcium, and what's not to like about that?

I can't provide sources for this information at the moment, but I did about 4 hour's research on it a year ago and turned up a fair amount.

I