Daily Vitamins

Jun 21, 2007 11:17

A friend recently asked my thoughts about taking regular, old-fashioned vitamins. Here was my response, for all to enjoy.

Regular, old-fashioned vitamins are generally fine. Though, some of them are now adding other "supplements" which may or may not add to their effects positively. In the realm of vitamins, there are a couple things of which you should be wary.

Products containing "super" doses of vitamins are likely not the best choice. It is okay, but generally unnecessary, to take somewhat more than the Reference Daily Intake (RDI) (previously known as the Recommended Daily Allowance) of the water soluble vitamins (primarily B and C). Excess amounts of these vitamins are just eliminated from the body. Of course, your body has to work a little bit to get rid of them. It can be rather harmful to take too much of the fat soluble vitamins (primarily A, D, E, and K), as they can accumulate in body tissue and lead to adverse effects over time.

Also, products claiming to be better or more extensively absorbed are generally not significantly so. The pH of the stomach is so acidic that it completely breaks down most ingested tablets in a matter of minutes; capsules even faster. The absorption of vitamins generally only depends on their dissolution. Thus, within a few minutes, most vitamin tablets and capsules are completely available for absorption in the intestine. It actually costs more to make a dosage form that will not break down so quickly. Just compare the prices of regular (immediate-release) and enteric-coated (delayed-release) aspirin. Manufacturers of inexpensive vitamin supplements do not pay extra to make their products in formulations that prevent acid-mediated breakdown. Even people who use stomach acid reducers on a regular basis maintain a low enough pH to dissolve most tablets and capsules quickly.

If you wish to take a daily vitamin, which I recommend if you think your diet is inadequate, get an inexpensive multivitamin with minerals with at or slightly above (100-300%) of the RDI for water soluble vitamins and at or slightly below (70-100%) of the RDI for fat soluble vitamins. Calcium and iron are the two minerals that are most often insufficient from many Americans' diets. So, those are important in a supplement. Also, if you are on a very strict low salt diet, look for a supplement with iodine. (Americans get most of their iodine from iodized salt.)

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