I guess my discomfort with IU is that it seems to be a completely arbitrary
unit that tells me absolutely nothing about how much of the stuff I am
actually getting, or even what that stuff is. 1 IU of one nutrient doesn't
seem to have any relation at all to 1 IU of another nutrient. One might
measure in milligrams while the other measures in nanograms, a million times
less. Would it be possible to give doses in masses "equivalent to" some
standard preparation, with the understanding that the actual mass might be
different? For example, could they give Vit. A doses in �g of Retinol
equivalents or something? Perhaps abbreviated as Vit. A (RE) 1 �g. We do
this with radiation (the sievert, an SI unit, which measures the dose
"equivalent to" 1 J/kg of some standard) and it seems to make more sense to
me. But note that I am not suggesting we invent new SI units for vitamins!
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On
> Behalf Of Scott Clauss
> Sent: 2000 December 4 Monday 12:42
> To: U.S. Metric Association
> Subject: [USMA:9520] Re: International Unit
>
>
> See below. International unit dosing is the only way I see to
> sell some of
> these compound classes without ridiculously expensive and
> needless separtion
> and clean-up procedures.
>
> Scott C.
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On
> > Behalf Of Dennis Brownridge
> > Sent: Saturday, December 02, 2000 3:22 PM
> > To: U.S. Metric Association
> > Subject: [USMA:9505] Re: International Unit
> >
> >
> > Rowlett's dictionary of units reports that, for "standard
> preparations," 1
> > IU =
> >
> > 0.3 �g of vitamin A
>
> Vitamin A occurs in two principal forms in nature: retinol, which is found
> only in animal sources, and certain carotenoids, the best known
> of which is
> beta-carotene. beta-Carotene can be converted to retinol in the
> body. So if
> you were selling pure retinol you could probably sell by the
> mg/dose, but if
> you are selling a mixture of carotenoids, each with its own convertion to
> retinol efficiency you wouldn't really be able to sell by mass/dose.
>
> > 50 �g of vitamin C
>
> Is one compound, ascorbic acid, so is usually sold as mg/tablet.
>
> > 25 ng of vitamin D
>
> Vitamin D is the generic name for a group of steroid-like substances with
> anti-rachitic activity. It is found only in animals. The two most
> prominent
> members of this group are ergocalciferol (vitamin D2) and cholecalciferol
> (vitamin D3).
>
> > 0.66 mg of vitamin E
>
> Vitamin E is the collective name for various tocopherols and tocotrienols.
> The most active form is of vitamin E is alpha-tocopherol.
>
> > 45.5 �g of insulin
>
> Is a large protein hormone made these days by fermentation with
> bioengineered bacteria or yeasts, so in addition to those 45.5
> �g, activity
> also depends on whether some of the hormone has lost its structural
> integrity during clean up, and what other inactive protein
> fragments may be
> present. Weighing the extract would not tell that. They may use diabetic
> animals to test the response and establish the activity of a
> batch, and this
> would be given in international units/dose.
>
> > 0.6 �g penicillin
>
> Is an antibiotic of specific structure, so should be sold by mg/dose. The
> structure has been tweeked chemically to counteract bacterial resisitance,
> but these are given different names, eg Ampicillin, Amoxicillin, etc.
>
>
