Essential amino acid requirements
dunns99 at erols.com
Thu Dec 16 05:47:01 EST 1999
> In article <3857B74A.802 at erols.com>, Stuart Dunn <dunns99 at erols.com> wrote:
> > > BTW, If excess calcium is appearing in the urine then that is a marked
> > > sign of a kidney disorder. ~10mg of calcium is removed by glomuelar
> > > filtration BUT ~9.82mg is readsorbed in the proxiamal and distal tubules.
> > > Thus about 175mg is all that will appear in the urine on any given day.
> > And if only a tenth of the calcium eaten is absorbed, this works out to
> > be 1750 a day that must be eaten. Either you have to megadose on calcium
> > or use an easily absorbed form.
> Roughly speaking, you should eat about 1 g of calcium a day. 500 mg will
> be adsorbed into the calcium pool in the body. Your body will secrete
> about 325 mg into the gut. This means that the net absorption from diet
> is about 175 mg/day.
Less than 500mg will be absorbed from 1000mg if your diet contains large
amounts of phytic acid, or if you rely on poorly absorbed calcium
sources like milk.
If you megadose on calcium, then the numbers
> relating to adsorption will not change but the numbers relating to
> excretion will. What your body does not need, it discards.
This doesn't make calcium megadoses safe. Many calcium supplements have
warnings against taking more than 2000mg a day on a regular basis
because doing so can cause kidney stones.
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