Do Your Vitamins Pass The Test?
A reader in Fort Collins, Colorado, raises a troubling question. How do you know that your vitamin pills are being absorbed in your digestive tract? He also asks about the reliability of a home test with vinegar. You do it this way: immerse the pill in enough household vinegar to cover it and let it stand for one hour (stir it a bit if you wish). The vinegar should cloud up, and the pill should at least disintegrate (fall into pieces), if not completely dissolve. If it remains intact, there's a chance it won't disintegrate in your stomach, but will pass right through you.
Home tests like this may tell you something, but they are only a rough approximation of what happens in the stomach, according to Will Brown, Senior Scientific Associate at the U.S. Pharmacopeia (USP), an independent, nonprofit testing organization. Not only is the test unreliable, but you would have trouble getting your money back if you tried to return the bottle of pills that flunked the test.
Your best bet is to buy vitamins and minerals with "USP" on the label. This means that the product meets USP standards, including one for disintegration, and has been tested under controlled laboratory conditions. The USP tests don't guarantee absorption of all nutrients—absorbability is very difficult to test or predict—but if a pill does disintegrate in the digestive tract, that improves the chances that nutrients will be absorbed by the body.
Vitamins and minerals do not have to conform to USP standards to be marketed in this country. Indeed, most brand-name vitamins are not labeled USP, because the manufacturer either doesn't want to do the tests, or prefers to guarantee the vitamin via the brand name. You'll notice on some labels such scientific-sounding claims as "potency guaranteed," "laboratory tested," or "high potency assured." All this may or may not mean something without USP on the label. Some non-USP pills do disintegrate, but a recent test at Tufts University of five non-USP vitamin pills showed that two of the five did not—and thus may be a waste of money. Tufts used USP testing procedures.
What about gel caps, such as most vitamin E? Disintegration shouldn't be a worry, in part because the vitamin inside is liquid.
What to do? The Wellness Letter recommends vitamin C (250 to 500 milligrams a day) and E supplements (200 to 800 IU), as well as calcium and multivitamins for some people. Buy products with USP on the label. These tend to be generic or store brands, and thus they will be cheaper anyway. There's no guarantee that you'll absorb the vitamins, but your chances will be greatly improved. Of course, it's possible for a company to add "USP" to its label without testing—the company wouldn't get caught. Better regulation in this area would be a real help to consumers.
UC Berkeley Wellness Letter, November
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